Publications

  • Journal Articles 166

    • 2017

      • Leicht J, Manoli Y A 2.6μW-1.2mW Autonomous Electromagnetic Vibration Energy Harvester Interface IC with Conduction-Angle-Controlled MPPT and up to 95% Efficiency 2017 IEEE Journal of Solid-State Circuits (JSSC), volume: 52, issue: 9, page(s): 2448 - 2462
      • Nitschke K, Kostering L, Finkel L, Weiller C, Kaller CP A Meta-analysis on the neural basis of planning: Activation likelihood estimation of functional brain imaging results in the Tower of London task. 2017 Hum Brain Mapp, volume: 38, issue: 1, page(s): 396 - 413
      • Boehler C, Kleber C, Martini N, Xie Y, Dryg I, Stieglitz T, Hofmann UG, Asplund M Actively controlled release of Dexamethasone from neural microelectrodes in a chronic in vivo study. 2017 Biomaterials, volume: 129, page(s): 176 - 187
        Show abstract Stable interconnection to neurons in vivo over long time-periods is critical for the success of future advanced neuroelectronic applications. The inevitable foreign body reaction towards implanted materials challenges the stability and an active intervention strategy would be desirable to treat inflammation locally. Here, we investigate whether controlled release of the anti-inflammatory drug Dexamethasone from flexible neural microelectrodes in the rat hippocampus has an impact on probe-tissue integration over 12 weeks of implantation. The drug was stored in a conducting polymer coating (PEDOT/Dex), selectively deposited on the electrode sites of neural probes, and released on weekly basis by applying a cyclic voltammetry signal in three electrode configuration in fully awake animals. Dex-functionalized probes provided stable recordings and impedance characteristics over the entire chronic study. Histological evaluation after 12 weeks of implantation revealed an overall low degree of inflammation around all flexible probes whereas electrodes exposed to active drug release protocols did have neurons closer to the electrode sites compared to controls. The combination of flexible probe technology with anti-inflammatory coatings accordingly offers a promising approach for enabling long-term stable neural interfaces.
        Open publication
      • Scheller E, Peter J, Schumacher LV, Lahr J, Mader I, Kaller CP, Kloppel S APOE moderates compensatory recruitment of neuronal resources during working memory processing in healthy older adults. 2017 Neurobiol Aging, volume: 56, page(s): 127 - 137
      • Schmidt CS, Schumacher LV, Romer P, Leonhart R, Beume L, Martin M, Dressing A, Weiller C, Kaller CP Are semantic and phonological fluency based on the same or distinct sets of cognitive processes? Insights from factor analyses in healthy adults and stroke patients. 2017 Neuropsychologia, volume: 99, page(s): 148 - 155
      • Gallinaro JV, Rotter S Associative properties of structural plasticity based on firing rate homeostasis in a balanced recurrent network of spiking neurons 2017 arXiv 1706.02912 [q-bio.NC], page(s): 1 - 27
        Show abstract Hebbian and homeostatic plasticity have been studied extensively in the past, both experimentally and theoretically, but many aspects of their interaction remain to be elucidated. Hebbian plasticity is thought to shape neuronal connectivity during development and learning, whereas homeostatic plasticity would stabilize network activity. Here we investigate another aspect of this interaction, which is whether Hebbian associative properties can also emerge as a network effect from a plasticity rule based on homeostatic principles on the neuronal level. The maturation of cortical networks during sensory experience is an ideal case to explore this question. Excitatory neurons in the visual cortex of rodents have been shown to connect preferentially to neurons that respond to similar visual features. Since this connectivity bias is not existent at the time of eye opening, but only after some weeks of visual experience, it has been suggested that plastic mechanisms are responsible for the changes taking place during sensory stimulation. We consider a structural plasticity rule driven by a homeostasis of firing rate in a recurrent network of leaky integrate-and-fire (LIF) neurons exposed to external input that is modulated by the orientation of a visual stimulus. Our results show that feature specific connectivity, similar to what has been experimentally observed in rodent visual cortex, can emerge out of a random balanced network of LIF neurons with a plasticity rule that is not explicitly dependent on correlations between pre- and postsynaptic neuronal activity. The synaptic association of neurons responding to similar stimulus features occurs as a side-effect of controlling the activity of individual neurons. The experience dependent structural changes that are triggered by simulation are long lasting and decay only slowly when the neurons are exposed again to non modulated external input. arXiv 1706.02912 [q-bio.NC], 2017 (pdf)
        Open publication
      • Schulze-Bonhage A Brain stimulation as a neuromodulatory epilepsy therapy. 2017 Seizure-eur J Epilep, volume: 44, page(s): 169 - 175
      • Nakagawa JM, Donkels C, Fauser S, Schulze-Bonhage A, Prinz M, Zentner J, Haas CA Characterization of focal cortical dysplasia with balloon cells by layer-specific markers: evidence for differential vulnerability of interneurons 2017 Epilepsia, volume: 58, issue: 4, page(s): 635 - 645
      • Kohler F, Gkogkidis CA, Bentler C, Wang X, Gierthmuehlen M, Fischer J, Stolle C, Reindl LM, Rickert J, Stieglitz T, Ball T, Schuettler M Closed-loop interaction with the cerebral cortex: A review of wireless implant technology. 2017 Brain-Computer Interfaces, volume: 4, issue: 3, page(s): 146 - 154
      • Schirrmeister R, Springenberg JT, Fiederer LDJ, Glasstetter M, Eggensperger K, Tangerman, M, Hutter F, Burgard W, Ball T Deep learning with convolutional neural networks for EEG decoding and visualization. 2017 Hum Brain Mapp, volume: 38, issue: 11, page(s): 5391 - 5420
      • Schirrmeister Robin, Springenberg Jost, Fiederer Lukas, Glasstetter Martin, Eggensperger Katharina, Tangermann Michael, Hutter Frank, Burgard Wolfram, Ball Tonio Deep learning with convolutional neural networks for brain mapping and decoding of movement-related information from the human EEG 2017 ArXiv e-prints
        Show abstract Deep learning with convolutional neural networks (deep ConvNets) has revolutionized computer vision through end-to-end learning, i.e. learning from the raw data. Now, there is increasing interest in using deep ConvNets for end-to-end EEG analysis. However, little is known about many important aspects of how to design and train ConvNets for end-to-end EEG decoding, and there is still a lack of techniques to visualize the informative EEG features the ConvNets learn. Here, we studied deep ConvNets with a range of different architectures, designed for decoding imagined or executed movements from raw EEG. Our results show that recent advances from the machine learning field, including batch normalization and exponential linear units, together with a cropped training strategy, boosted the deep ConvNets decoding performance, reaching or surpassing that of the widely-used filter bank common spatial patterns (FBCSP) decoding algorithm. While FBCSP is designed to use spectral power modulations, the features used by ConvNets are not fixed a priori. Our novel methods for visualizing the learned features demonstrated that ConvNets indeed learned to use spectral power modulations in the alpha, beta and high gamma frequencies. These methods also proved useful as a technique for spatially mapping the learned features, revealing the topography of the causal contributions of features in different frequency bands to decoding the movement classes. Our study thus shows how to design and train ConvNets to decode movement-related information from the raw EEG without handcrafted features and highlights the potential of deep ConvNets combined with advanced visualization techniques for EEG-based brain mapping.
      • Schirrmeister Robin, Springenberg Jost, Fiederer Lukas, Glasstetter Martin, Eggensperger Katharina, Tangermann Michael, Hutter Frank, Burgard Wolfram, Ball Tonio Deep learning with convolutional neural networks for EEG decoding and visualization 2017 Human Brain Mapping
      • Umarova RM, Beume L, Reisert M, Kaller CP, Kloppel S, Mader I, Glauche V, Kiselev VG, Catani M, Weiller C Distinct white matter alterations following severe stroke: Longitudinal DTI study in neglect. 2017 Neurology, volume: 88, issue: 16, page(s): 1546 - 1555
      • Janz P, Schwaderlapp N, Heining K, Häussler U, Korvink JG, von Elverfeldt D, Hennig J, Egert U, LeVan P, Haas CA* Early tissue damage and microstructural reorganization predict disease severity of experimental epilepsy 2017 Elife, volume: 6, page(s): e25742
      • Kellmeyer P Ethical and Legal Implications of the Methodological Crisis in Neuroimaging. 2017 Camb Q Healthc Ethic, volume: 26, issue: 4, page(s): 530 - 554
      • Verhoeven Thibault, Hübner David, Tangermann Michael, Müller Klaus-Robert, Dambre Joni, Kindermans Pieter-Jan Improving zero-training brain-computer interfaces by mixing model estimators 2017 Journal of Neural Engineering, volume: 14, issue: 3, page(s): 036021
        Show abstract Objective. Brain-computer interfaces (BCI) based on event-related potentials (ERP) incorporate a decoder to classify recorded brain signals and subsequently select a control signal that drives a computer application. Standard supervised BCI decoders require a tedious calibration procedure prior to every session. Several unsupervised classification methods have been proposed that tune the decoder during actual use and as such omit this calibration. Each of these methods has its own strengths and weaknesses. Our aim is to improve overall accuracy of ERP-based BCIs without calibration.Approach. We consider two approaches for unsupervised classification of ERP signals. Learning from label proportions (LLP) was recently shown to be guaranteed to converge to a supervised decoder when enough data is available. In contrast, the formerly proposed expectation maximization (EM) based decoding for ERP-BCI does not have this guarantee. However, while this decoder has high variance due to random initialization of its parameters, it obtains a higher accuracy faster than LLP when the initialization is good.We introduce a method to optimally combine these two unsupervised decoding methods, letting one method’s strengths compensate for the weaknesses of the other and vice versa. The new method is compared to the aforementioned methods in a resimulation of an experiment with a visual speller.Main Results. Analysis of the experimental results shows that the new method exceeds the performance of the previous unsupervised classification approaches in terms of ERP classification accuracy and symbol selection accuracy during the spelling experiment. Furthermore, the method shows less dependency on random initialization of model parameters and is consequently more reliable.Significance. Improving the accuracy and subsequent reliability of calibrationless BCIs makes these systems more appealing for frequent use.
      • Deniz T, Rotter S Joint statistics of strongly correlated neurons via dimensionality reduction Journal of Physics A: Mathematical and Theoretical 50(25): 254002, 2017 2017 J Phys A-math Theor, volume: 50, issue: 25, page(s): 1 - 35
        Show abstract The relative timing of action potentials in neurons recorded from local cortical networks often shows a non-trivial dependence, which is then quantified by cross-correlation functions. Theoretical models emphasize that such spike train correlations are an inevitable consequence of two neurons being part of the same network and sharing some synaptic input. For non-linear neuron models, however, explicit correlation functions are difficult to compute analytically, and perturbative methods work only for weak shared input. In order to treat strong correlations, we suggest here an alternative non-perturbative method. Specifically, we study the case of two leaky integrate-and-fire neurons with strong shared input. Correlation functions derived from simulated spike trains fit our theoretical predictions very accurately. Using our method, we computed the non-linear correlation transfer as well as correlation functions that are asymmetric due to inhomogeneous intrinsic parameters or unequal input.
        Open publication
      • Hübner David, Verhoeven Tibault, Schmid Konstantin, Müller Klaus-Robert, Tangermann Michael, Kindermans Pieter-Jan Learning from Label Proportions in Brain-Computer Interfaces: Online Unsupervised Learning with Guarantees 2017 ArXiv e-prints
      • Alt M, Fiedler E, Rudmann L, Ordonez J, Ruther P, Stieglitz T Let There Be Light — Optoprobes for Neural Implants 2017 P Ieee, volume: 105, issue: 1, page(s): 101 - 138
        Show abstract Over the past decades, optical technologies have entered neural implant technologies. Applications such as optogenetics, near-infrared spectroscopy (NIRS), and direct-near-infrared stimulation (NIS) request technical devices that combine electrical and optical recording as well as stimulation capabilities using light sources and/or optical sensors. Optoprobes are the technical devices that meet these requirements. This paper provides basic insights into optogenetic mechanisms, the background of NIRS and NIS, and focuses on fundamental requirements of technical systems from a biological background. The state of the art of optoprobes is reviewed and attention is drawn on the potential long-term stability of these technical devices for chronic neural implants. Further, material selection for stiff and flexible devices, applicable light sources, waveguide and coupling concepts, packaging paradigms as well as system assembly and integration aspects are discussed in view of biocompatible and biostable devices. This paper also considers the physical background of light scattering and heat generation when light sources are implanted into biological tissue.
      • Wang X, Gkogkidis A, Iljina O, Fiederer L, Henle C, Mader I, Kaminsky J, Stieglitz T, Gierthmuehlen M, Ball T Mapping the fine structure of cortical activity with different micro-ECoG electrode array geometries. 2017 J Neural Eng, volume: 14, issue: 5, page(s): 056004
      • Okujeni S, Kandler S, Egert U Mesoscale architecture shapes initiation and richness of spontaneous network activity. 2017 J Neurosci, volume: 37, issue: 14, page(s): 3972 - 3987
      • Gremmelspacher T, Gerlach J, Hubbe A, Haas CA, Häussler U Neurogenic processes are induced by very short periods of voluntary wheel-running in male mice 2017 Front Neurosci-switz, volume: 11, issue: 385
      • Iljina O, Derix J, Schirrmeister RT, Schulze-Bonhage A, Auer P, Aertsen A, Ball T Neurolinguistic and machine-learning perspectives on direct speech BCIs for restoration of naturalistic communication. 2017 Brain-Computer Interfaces, volume: 4, issue: 3, page(s): 186 - 199
      • Knapp F, Viechtbauer W, Leonhart R, Nitschke K, Kaller CP Planning performance in schizophrenia patients: a meta-analysis of the influence of task difficulty and clinical and sociodemographic variables. 2017 Psychol Med, page(s): 1 - 15
      • Xie Y, Harsan LA, Bienert T, Kirch RD, von Elverfeldt D, Hofmann UG Quantitative Evaluation of in vivo SD-OCT Measurement of Rat Brain. 2017 Biomed Opt Express, volume: 8, issue: 2, page(s): 593 - 607
      • A. Müller, M. C. Wapler, U. Wallrabe Segmented Bessel beams 2017 Opt Express, volume: 25, page(s): 22640 - 22647
      • Deniz T, Rotter S Solving the two-dimensional Fokker-Planck equation for strongly correlated neurons 2017 Phys Rev E, issue: 95, page(s): 012412-1 - 012412-12
        Show abstract Pairs of neurons in brain networks often share much of the input they receive from other neurons. Due to essential nonlinearities of the neuronal dynamics, the consequences for the correlation of the output spike trains are generally not well understood. Here we analyze the case of two leaky integrate-and-fire neurons using an approach which is nonperturbative with respect to the degree of input correlation. Our treatment covers both weakly and strongly correlated dynamics, generalizing previous results based on linear response theory.
        Open publication
      • Janz P, Savanthrapadian S, Häussler U, Kilias A, Nestel S, Kretz O, Kirsch M, Bartos M, Egert U, Haas CA Synaptic remodeling of entorhinal input contributes to an aberrant hippocampal network in temporal lobe epilepsy 2017 Cereb Cortex, volume: 27, issue: 3, page(s): 2348 - 2364 Open publication
      • Peters M, Wielsch B, Boltze J The role of SUMOylation in cerebral hypoxia and ischemia 2017 Neurochem Int, volume: 107, page(s): 66 - 77
      • Donkels C, Pfeifer D, Janz P, Huber S, Nakagawa J, Prinz M, Schulze-Bonhage A, Weyerbrock A, Zentner J, Haas CA Whole transcriptome screening reveals myelination deficits in dysplastic human temporal neocortex 2017 Cereb Cortex, volume: 27, issue: 2, page(s): 1558 - 1572 Open publication
      • Huggins Jane, Guger Christoph, Ziat Mounia, Zander Thorsten, Taylor Denise, Tangermann Michael, Soria-Frisch Aureli, Simeral John, Scherer Reinhold, Rupp Rüdiger, Ruffini Giulio, Robinson Douglas, Ramsey Nick, Nijholt Anton, Müller-Putz Gernot, McFarland Workshops of the Sixth International Brain-Computer Interface Meeting: brain-computer interfaces past, present, and future 2017 Brain-Computer Interfaces, volume: 4, issue: 1-2, page(s): 3 - 36
    • 2016

      • Pinnell R, Almajidy RK, Kirch RD, Cassell JC, Hofmann UG A Wireless EEG Recording Method for use Inside the Water Maze. 2016 Plos One, volume: 11, issue: 2, page(s): 1 - 15
        Show abstract With the continued miniaturisation of portable embedded systems, wireless EEG recording techniques are becoming increasingly prevalent in animal behavioural research. However, in spite of their versatility and portability, they have seldom been used inside water-maze tasks designed for rats. As such, a novel 3D printed implant and waterproof connector is presented, which can facilitate wireless water-maze EEG recordings in freely-moving rats, using a commercial wireless recording system (W32; Multichannel Systems). As well as waterproofing the wireless system, battery, and electrode connector, the implant serves to reduce movement-related artefacts by redistributing movement-related forces away from the electrode connector. This implant/connector was able to successfully record high-qual- ity LFP in the hippocampo-striatal brain regions of rats as they undertook a procedural- learning variant of the double-H water-maze task. Notably, there were no significant perfor- mance deficits through its use when compared with a control group across a number of met- rics including number of errors and speed of task completion. Taken together, this method can expand the range of measurements that are currently possible in this diverse area of behavioural neuroscience, whilst paving the way for integration with more complex behaviours.
      • Heizmann S, Kilias A, Ruther P, Egert U, Asplund M Active Control of Dye Release for Neuronal Tracing using PEDOT-PSS Coated Electrodes. 2016 Ieee T Neur Sys Reh
      • Loosli SV, Rahm B, Unterrainer JM, Mader I, Weiller C, Kaller CP Age differences in behavioral and neural correlates of proactive interference: Disentangling the role of overall working memory performance. 2016 Neuroimage, volume: 127, page(s): 376 - 386
      • Kostering L, Schmidt CS, Weiller C, Kaller CP Analyses of Rule Breaks and Errors During Planning in Computerized Tower Tasks: Insights From Neurological Patients. 2016 Arch Clin Neuropsych, volume: 31, issue: 7, page(s): 738 - 753
      • N.M. Mallet, R. Schmidt, D.K. Leventhal, F. Chen, N. Amer, T. Boraud, J.D. Berke Arkypallidal cells send a stop signal to striatum 2016 Neuron, volume: 89, page(s): 1 - 9
      • Kaller CP, Debelak R, Kostering L, Egle J, Rahm B, Wild PS, Blettner M, Beutel ME, Unterrainer JM Assessing Planning Ability Across the Adult Life Span: Population-Representative and Age-Adjusted Reliability Estimates for the Tower of London (TOL-F). 2016 Arch Clin Neuropsych, volume: 31, issue: 2, page(s): 148 - 164
      • Debelak R, Egle J, Kostering L, Kaller CP Assessment of planning ability: Psychometric analyses on the unidimensionality and construct validity of the Tower of London Task (TOL-F). 2016 Neuropsychology, volume: 30, issue: 3, page(s): 346 - 360
      • Kumar SS, Wulfing J, Okujeni S, Boedecker J, Riedmiller M, Egert U Autonomous optimization of targeted stimulation of neuronal networks. 2016 Plos Comput Biol, volume: 12, issue: 8, page(s): e1005054
      • Martin M, Nitschke K, Beume L, Dressing A, Buhler LE, Ludwig VM, Mader I, Rijntjes M, Kaller CP, Weiller C Brain activity underlying tool-related and imitative skills after major left hemisphere stroke. 2016 Brain, volume: 139, issue: Pt 5, page(s): 1497 - 1516
      • Martin M, Dressing A, Bormann T, Schmidt CS, Kummerer D, Beume L, Saur D, Mader I, Rijntjes M, Kaller CP, Weiller C Componential Network for the Recognition of Tool-Associated Actions: Evidence from Voxel-based Lesion-Symptom Mapping in Acute Stroke Patients. 2016 Cereb Cortex
      • Rieger SB, Pfau J, Stieglitz T, Asplund M, Ordonez JS Concept and Development of an Electronic Framework Intended for Electrode and Surrounding Environment Characterization In Vivo. 2016 Sensors-basel, volume: 17, issue: 1
        Show abstract Abstract There has been substantial progress over the last decade towards miniaturizing implantable microelectrodes for use in Active Implantable Medical Devices (AIMD). Compared to the rapid development and complexity of electrode miniaturization, methods to monitor and assess functional integrity and electrical functionality of these electrodes, particularly during long term stimulation, have not progressed to the same extent. Evaluation methods that form the gold standard, such as stimulus pulse testing, cyclic voltammetry and electrochemical impedance spectroscopy, are either still bound to laboratory infrastructure (impractical for long term in vivo experiments) or deliver no comprehensive insight into the material’s behaviour. As there is a lack of cost effective and practical predictive measures to understand long term electrode behaviour in vivo, material investigations need to be performed after explantation of the electrodes. We propose the analysis of the electrode and its environment in situ, to better understand and correlate the effects leading to electrode failure. The derived knowledge shall eventually lead to improved electrode designs, increased electrode functionality and safety in clinical applications. In this paper, the concept, design and prototyping of a sensor framework used to analyse the electrode’s behaviour and to monitor diverse electrode failure mechanisms, even during stimulation pulses, is presented. We focused on the electronic circuitry and data acquisition techniques required for a conceptual multi-sensor system. Functionality of single modules and a prototype framework have been demonstrated, but further work is needed to convert the prototype system into an implantable device. In vitro studies will be conducted first to verify sensor performance and reliability.
      • Argiti K, Joseph K, Mottaghi S, Feuerstein TJ, Hofmann UG Deep brain stimulation: increasing efficiency by alternative waveforms 2016 Current Directions in Biomedical Engineering, volume: 2, issue: 1, page(s): 145 - 148
      • Mechling A.E., Arefin T., Lee H.L., Bienert T., Reisert M., Ben Hamida S., Darcq E., Ehrlich A., Gaveriaux-Ruff C., Parent M. J., Rosa-Neto P., Hennig J., von Elverfeldt D., Kieffer B.L., Harsan L.A. Deletion of the mu opioid receptor gene in mice reshapes the reward-aversion connectome 2016 Proceedings of the National Academy of Sciences of the United States of America, volume: 113, issue: 41, page(s): 11603 - 11608
        Show abstract Connectome genetics seeks to uncover how genetic factors shape brain functional connectivity; however, the causal impact of a single gene's activity on whole-brain networks remains unknown. We tested whether the sole targeted deletion of the mu opioid receptor gene (Oprm1) alters the brain connectome in living mice. Hypothesis-free analysis of combined resting-state fMRI diffusion tractography showed pronounced modifications of functional connectivity with only minor changes in structural pathways. Fine-grained resting-state fMRI mapping, graph theory, and intergroup comparison revealed Oprm1-specific hubs and captured a unique Oprm1 gene-to-network signature. Strongest perturbations occurred in connectional patterns of pain/aversion-related nodes, including the mu receptor-enriched habenula node. Our data demonstrate that the main receptor for morphine predominantly shapes the so-called reward/aversion circuitry, with major influence on negative affect centers.
      • Martin M, Beume L, Kummerer D, Schmidt CS, Bormann T, Dressing A, Ludwig VM, Umarova RM, Mader I, Rijntjes M, Kaller CP, Weiller C Differential Roles of Ventral and Dorsal Streams for Conceptual and Production-Related Components of Tool Use in Acute Stroke Patients. 2016 Cereb Cortex, volume: 26, issue: 9, page(s): 3754 - 3771
      • Dressing A, Nitschke K, Kummerer D, Bormann T, Beume L, Schmidt CS, Ludwig VM, Mader I, Willmes K, Rijntjes M, Kaller CP, Weiller C, Martin M Distinct Contributions of Dorsal and Ventral Streams to Imitation of Tool-Use and Communicative Gestures. 2016 Cereb Cortex
      • Sahasranamam A, Vlachos I, Aertsen A, Kumar A Dynamical state of the network determines the efficacy of single neuron properties in shaping the network activity. 2016 Sci Rep-uk, volume: 6, page(s): 26029
      • Levan P., Zhang S., Knowles B., Zaitsev M., Hennig J. EEG-fMRI Gradient Artifact Correction by Multiple Motion-Related Templates 2016 Ieee T Bio-med Eng, volume: 63, issue: 12, page(s): 2647 - 2653
        Show abstract OBJECTIVES: In simultaneous electroencephalography (EEG) and functional magnetic resonance imaging (fMRI), artifacts on the EEG arise from the switching of magnetic field gradients in the MR scanner. These artifacts depend on head position, and are, therefore, difficult to remove in the presence of subject motion. In this study, gradient artifacts are modeled by multiple templates extracted from externally recorded motion information.METHODS: Gradient artifact correction was performed in EEG-fMRI recordings by estimating artifactual templates modulated by slowly varying splines, as well as head position information. The EEG signal quality was then compared following two common methods: averaged artifact subtraction (AAS) and optimal basis sets (OBS).RESULTS: Artifact correction using multiple templates estimated from splines or motion time courses outperformed the existing AAS and OBS approaches, as quantified by root-mean-square power across gradient epochs. Improvements were mostly seen in posterior EEG channels, where most of the residual artifacts are seen following the AAS and OBS methods. Residual spectral power was comparable to that of EEG signals recorded without fMRI scanning.CONCLUSION: Gradient artifacts can be well modeled by multiple templates estimated from head position information, resulting in an effective artifact removal.SIGNIFICANCE: This method can facilitate EEG-fMRI of uncooperative subjects in whom motion is inevitable, for example, to investigate high-frequency EEG activity in which gradient artifacts are particularly prominent.
      • Fiederer L, Lahr J, Vorwerk J, Lucka F, Wolters C, Aertsen A, Schulze-Bonhage A, Ball T Electrical Stimulation of the Human Cerebral Cortex by Extracranial Muscle Activity:Effect Quantification with Intracranial EEG and FEM Simulations. 2016 Ieee T Bio-med Eng, volume: 63, issue: 12, page(s): 2552 - 2563
      • Bikis C, Janz P, Schulz G, Schweighauser G, Hench J, Thalmann P, Deyhle H, Chicherova N, Rack A, Khimchenko A, Hieber SE, Mariani L, Haas CA, Müller B High-resolution synchrotron radiation-based phase tomography of the healthy and epileptic brain 2016 Proc. of SPIE, volume: 9967, page(s): 996706-1 - 996706-11
      • Oliveira A, Ordonez J, Ashouri Vajari D, Eickenscheidt M, Stieglitz T Laser-induced carbon pyrolysis of electrodes for neural interface systems 2016 European Journal of Translational Myology, volume: 26, issue: 3
        Show abstract The objective of this work is to produce a laser- fabricated polymer-metal-polymer electrode with the merit of a carbon-based coating as the active site. A 10 μm-thick layer of parylene-C is used serving as the insulation layer in which the active site is locally laser-pyrolyzed. Our preliminary results show that the proposed method is promising in terms of fabrication feasibility and desired electrochemical capabilities.
      • Heers M, Chowdhury RA, Hedrich T, Dubeau F, Hall JA, Lina JM, Grova C, Kobayashi E Localization Accuracy of Distributed Inverse Solutions for Electric and Magnetic Source Imaging of Interictal Epileptic Discharges in Patients with Focal Epilepsy. 2016 Brain Topogr, volume: 29, issue: 1, page(s): 162 - 181
      • Boehler C, Oberueber F, Schlabach S, Stieglitz T, Asplund M Long-Term Stable Adhesion for Conducting Polymers in Biomedical Applications: IrOx and Nanostructured Platinum Solve the Chronic Challenge. 2016 Acs Appl Mater Inter, page(s): 189 - 197
        Show abstract Conducting polymers (CPs) have frequently been described as outstanding coating materials for neural microelectrodes, providing significantly reduced impedance or higher charge injection compared to pure metals. Usability has until now, however, been limited by poor adhesion of polymers like poly(3,4-ethylenedioxythiophene) (PEDOT) to metallic substrates, ultimately precluding long-term applications. The aim of this study was to overcome this weakness of CPs by introducing two novel adhesion improvement strategies that can easily be integrated with standard microelectrode fabrication processes. Iridium Oxide (IrOx) demonstrated exceptional stability for PEDOT coatings, resulting in polymer survival over 10 000 redox cycles and 110 days under accelerated aging conditions at 60 °C. Nanostructured Pt was furthermore introduced as a purely mechanical adhesion promoter providing 10-fold adhesion improvement compared to smooth Pt substrates by simply altering the morphology of Pt. This layer can be realized in a very simple process that is compatible with any electrode design, turning nanostructured Pt into a universal adhesion layer for CP coatings. By the introduction of these adhesion-promoting strategies, the weakness of CP-based neural probes can ultimately be eliminated and true long-term stable use of PEDOT on neural probes will be possible in future electrode generations.
      • Hesse L., Masselter T., Leupold J., Spengler N., Speck T., Korvink JG Magnetic resonance imaging reveals functional anatomy and biomechanics of a living dragon tree 2016 Scientific Reports, volume: 6, page(s): 32685 - 32702
        Show abstract Magnetic resonance imaging (MRI) was used to gain in vivo insight into load-induced displacements of inner plant tissues making a non-invasive and non-destructive stress and strain analysis possible. The central aim of this study was the identification of a possible load-adapted orientation of the vascular bundles and their fibre caps as the mechanically relevant tissue in branch-stem-attachments of Dracaena marginata. The complex three-dimensional deformations that occur during mechanical loading can be analysed on the basis of quasi-three-dimensional data representations of the outer surface, the inner tissue arrangement (meristem and vascular system), and the course of single vascular bundles within the branch-stem-attachment region. In addition, deformations of vascular bundles could be quantified manually and by using digital image correlation software. This combination of qualitative and quantitative stress and strain analysis leads to an improved understanding of the functional morphology and biomechanics of D. marginata, a plant that is used as a model organism for optimizing branched technical fibre-reinforced lightweight trusses in order to increase their load bearing capacity.
      • Körbl K, Jacobs J, Herbst M, Zaitsev M, Schulze-Bonhage A, Hennig J, LeVan P Marker-based ballistocardiographic artifact correction improves spike identification in EEG-fMRI of focal epilepsy patients. 2016 Clin Neurophysiol, volume: 127, issue: 8, page(s): 2802 - 2811
      • Hamid AA, Pettibone JR, Mabrouk OS, Hetrick VL, Schmidt R, Vander Weele CM, Kennedy RT, Aragona BJ, Berke JD Mesolimbic dopamine signals the value of work. 2016 Nat Neurosci, volume: 19, issue: 1, page(s): 117 - 126
      • Egger K, Janz P, Döbrössy M, Bienert T, Reisert M, Obmann M, Glauche V, Haas CA, Harsan L, Urbach H, von Elverfeldt D Microstructural effects of a neuro-modulating drug evaluated by diffusion tensor tmaging 2016 Neuroimage, volume: 127, page(s): 1 - 10
      • Häussler U, Rinas K, Kilias A, Egert U, Haas CA Mossy fiber sprouting and pyramidal cell dispersion in the hippocampal CA2 region in a mouse model of temporal lobe epilepsy. 2016 Hippocampus, volume: 26, page(s): 577 - 588
      • Moritz CT, Ruther P, Goering S, Stett A, Ball T, Burgard W, Chudler EH, Rao RP New Perspectives on Neuroengineering and Neurotechnologies: NSF-DFG Workshop Report. 2016 Ieee T Bio-med Eng, volume: 63, issue: 7, page(s): 1354 - 1367
      • Abdo N, Stachniss C, Burgard W, Spinello L Organizing Objects by Predicting User Preferences Through Collaborative Filtering 2016 The International Journal of Robotics Research (IJRR)
        Show abstract As service robots become more and more capable of performing useful tasks for us, there is a growing need to teach robots how we expect them to carry out these tasks. However, different users typically have their own preferences, for example with respect to arranging objects on different shelves. As many of these preferences depend on a variety of factors including personal taste, cultural background, or common sense, it is challenging for an expert to pre-program a robot in order to accommodate all potential users. At the same time, it is impractical for robots to constantly query users about how they should perform individual tasks. In this work, we present an approach to learn patterns in user preferences for the task of tidying up objects in containers, e.g. shelves or boxes. Our method builds upon the paradigm of collaborative filtering for making personalized recommendations and relies on data from different users which we gather using crowdsourcing. To deal with novel objects for which we have no data, we propose a method that compliments standard collaborative filtering by leveraging information mined from the Web. When solving a tidy-up task, we first predict pairwise object preferences of the user. Then, we subdivide the objects in containers by modeling a spectral clustering problem. Our solution is easy to update, does not require complex modeling, and improves with the amount of user data. We evaluate our approach using crowdsourcing data from over 1200 users and demonstrate its effectiveness for two tidy-up scenarios. Additionally, we show that a real robot can reliably predict user preferences using our approach.
      • Gerlach J, Donkels C, Münzner G, Haas CA Persistent gliosis interferes with neurogenesis in organotypic hippocampal slice cultures 2016 Front Cell Neurosci, volume: 10, page(s): 131-1 - 131-17 Open publication
      • Kostering L, Leonhart R, Stahl C, Weiller C, Kaller CP Planning Decrements in Healthy Aging: Mediation Effects of Fluid Reasoning and Working Memory Capacity. 2016 J Gerontol B-psychol, volume: 71, issue: 2, page(s): 230 - 242
      • Meinel Andreas, Castaño-Candamil Sebastián, Reis Janine, Tangermann Michael Pre-Trial EEG-based Single-Trial Motor Performance Prediction to Enhance Neuroergonomics for a Hand Force Task 2016 Frontiers in Human Neuroscience, volume: 10, issue: 170
        Show abstract We propose a framework for building electrophysiological predictors of single-trial motor performance variations, exemplified for SVIPT, a sequential isometric force control task suitable for hand motor rehabilitation after stroke. Electroencephalogram (EEG) data of 20 subjects with mean age of 53 years was recorded prior to and during 400 trials of SVIPT. They were executed within a single session with the non-dominant left hand, while receiving continuous visual feedback of the produced force trajectories. The behavioral data showed strong trial-by-trial performance variations for five clinically relevant metrics, which accounted for reaction time as well as for the smoothness and precision of the produced force trajectory. 18 out of 20 tested subjects remained after preprocessing and entered offline analysis. Source Power Comodulation (SPoC) was applied on EEG data of a short time interval prior to the start of each SVIPT trial. For 11 subjects, SPoC revealed robust oscillatory EEG subspace components, whose bandpower activity are predictive for the performance of the upcoming trial. Since SPoC may overfit to non-informative subspaces, we propose to apply three selection criteria accounting for the meaningfulness of the features. Across all subjects, the obtained components were spread along the frequency spectrum and showed a variety of spatial activity patterns. Those containing the highest level of predictive information resided in and close to the alpha band. Their spatial patterns resemble topologies reported for visual attention processes as well as those of imagined or executed hand motor tasks. In summary, we identified subject-specific single predictors that explain up to 36% of the performance fluctuations and may serve for enhancing neuroergonomics of motor rehabilitation scenarios.
        Open publication
      • Umarova RM, Nitschke K, Kaller CP, Kloppel S, Beume L, Mader I, Martin M, Hennig J, Weiller C Predictors and signatures of recovery from neglect in acute stroke. 2016 Ann Neurol, volume: 79, issue: 4, page(s): 673 - 686
      • Hammer J, Pistohl T, Fischer J, Krsek P, Tomasek M, Marusic P, Schulze-Bonhage A, Aertsen A, Ball T Predominance of Movement Speed Over Direction in Neuronal Population Signals of Motor Cortex: Intracranial EEG Data and A Simple Explanatory Model. 2016 Cereb Cortex, volume: 26, issue: 6, page(s): 2863 - 2681
      • A. Müller, M. C. Wapler, U. T. Schwarz, M. Reisacher, K. Holc, O. Ambacher, U. Wallrabe Quasi-Bessel beams from asymmetric and astigmatic illumination sources 2016 Opt Express, volume: 24, issue: 15, page(s): 17433 - 17452
      • Vlachos I, Deniz T, Aertsen A, Kumar A Recovery of Dynamics and Function in Spiking Neural Networks with Closed-Loop Control. 2016 Plos Comput Biol, volume: 12, issue: 2, page(s): e1004720
      • Orcinha C, Münzner G, Gerlach J, Kilias A, Follo M, Egert U, Haas CA Seizure-induced motility of differentiated dentate granule cells is prevented by the central Reelin fragment 2016 Front Cell Neurosci, volume: 10, page(s): 183
      • Kellmeyer P, Cochrane T, Muller O, Mitchell C, Ball T, Fins JJ, Biller-Andorno N The Effects of Closed-Loop Medical Devices on the Autonomy and Accountability of Persons and Systems. 2016 Camb Q Healthc Ethic, volume: 25, issue: 4, page(s): 623 - 633
      • Fiederer LD, Vorwerk J, Lucka F, Dannhauer M, Yang S, Dumpelmann M, Schulze-Bonhage A, Aertsen A, Speck O, Wolters CH, Ball T The role of blood vessels in high-resolution volume conductor head modeling of EEG. 2016 Neuroimage, volume: 128, page(s): 193 - 208
      • Stieglitz T, Paul O, Wallrabe U, Ruther P Track U. BrainLinks-BrainTools-Methods and tools for neural engineering. 2016 Biomed Tech, volume: 61, issue: s1, page(s): 234 - 243
      • Loosli SV, Falquez R, Unterrainer JM, Weiller C, Rahm B, Kaller CP Training of resistance to proactive interference and working memory in older adults: a randomized double-blind study. 2016 Int Psychogeriatr, volume: 28, issue: 3, page(s): 453 - 467
      • Kiviniemi V., Wang X., Korhonen V., Keinänen T., Tuovinen T., Autio J., LeVan P., Keilholz S., Zang Y., Hennig J., Nedergaard M. Ultra-fast magnetic resonance encephalography of physiological brain activity - Glymphatic pulsation mechanisms? 2016 J Cerebr Blood F Met, volume: 36, issue: 6, page(s): 1033 - 1045
        Show abstract The theory on the glymphatic convection mechanism of cerebrospinal fluid holds that cardiac pulsations in part pump cerebrospinal fluid from the peri-arterial spaces through the extracellular tissue into the peri-venous spaces facilitated by aquaporin water channels. Since cardiac pulses cannot be the sole mechanism of glymphatic propulsion, we searched for additional cerebrospinal fluid pulsations in the human brain with ultra-fast magnetic resonance encephalography. We detected three types of physiological mechanisms affecting cerebral cerebrospinal fluid pulsations: cardiac, respiratory, and very low frequency pulsations. The cardiac pulsations induce a negative magnetic resonance encephalography signal change in peri-arterial regions that extends centrifugally and covers the brain in ≈1 Hz cycles. The respiratory ≈0.3 Hz pulsations are centripetal periodical pulses that occur dominantly in peri-venous areas. The third type of pulsation was very low frequency (VLF 0.001-0.023 Hz) and low frequency (LF 0.023-0.73 Hz) waves that both propagate with unique spatiotemporal patterns. Our findings using critically sampled magnetic resonance encephalography open a new view into cerebral fluid dynamics. Since glymphatic system failure may precede protein accumulations in diseases such as Alzheimer's dementia, this methodological advance offers a novel approach to image brain fluid dynamics that potentially can enable early detection and intervention in neurodegenerative diseases.
      • Pinnell R, Almajidy RK, Hofmann UG Versatile 3D-Printed Headstage Implant for Group Housing of Rats. 2016 J Neurosci Meth, volume: 257, page(s): 134 - 138
        Show abstract Highlights • A novel 3D-printed headstage was developed for protecting skull-mounted implants in rodents. • The socket allowed for successful chronic pair-housing of rats following stereotaxic surgery. • Rats were able to carry out a range of normal behaviours, with no significant implant damage observed. • This implant can help to improve the well-being of post-surgical rats, whilst reducing the cost of rodent upkeep
    • 2015

      • C. Boehler, M. Asplund A detailed insight into drug delivery from PEDOT based on analytical methods: effects and side-effects. 2015 J Biomed Mater Res A, volume: 103, issue: 3, page(s): 1200 - 1207
        Show abstract The possibility to release drugs from conducting polymers, like polypyrrole or poly(3,4-ethylenedioxythiophene) (PEDOT), has been described and investigated for a variety of different substances during the last years, showing a wide interest in these release systems. A point that has not been looked at so far however is the possibility of other substances, next to the intended ones, leaving the polymer film under the high voltage excursions during redox sweeping. In this study we target this weakness of commonly used detection methods by implementing a high precision analytical method (high-performance liquid chromatography) that allows a separation and subsequently a detailed quantification of all possible release products. We could identify a significantly more complex release behavior for a PEDOT:Dex system than has been assumed so far, revealing the active release of the monomer upon redox activation. The released EDOT could thereby be shown to result from the bulk material, causing a considerable loss of polymer (>10% during six release events) that could partly account for the observed degradation or delamination effects of drug-eluting coatings. The monomer leakage was found to be substantially higher for a PEDOT:Dex film compared to a PEDOT:PSS sample. This finding indicates an overestimation of drug release if side products are mistaken for the actual drug mass. Moreover the full picture of released substances implements the need for further studies to reduce the monomer leakage and identify possible adverse effects, especially in the perspective of releasing an anti-inflammatory substance for attenuation of the foreign body reaction toward implanted electrodes.
      • Dumpelmann M, Cosandier-Rimele D, Ramantani G, Schulze-Bonhage A A novel approach for multiscale source analysis and modeling of epileptic spikes. 2015 IEEE Eng Med Biol Soc, volume: 2015, page(s): 6634 - 6637
      • Köstering L, Schmidt CS, Egger K, Amtage F, Peter J, Klöppel S, Beume LA, Hoeren M, Weiller C, Kaller CP Assessment of planning performance in clinical samples: Reliability and validity of the Tower of London task (TOL-F). 2015 Neuropsychologia, volume: 75, page(s): 646 - 655
      • Bedner P, Dupper A, Hüttmann K, Müller J, Herde MK, Dublin P, Deshpande T, Schramm J, Häussler U, Haas CA, Henneberger C, Theis M, Steinhäuser C Astrocyte uncoupling as a cause of human temporal lobe epilepsy 2015 Brain, volume: 138, page(s): 1208 - 1222
      • Furlanetti LL, Coenen VA, Aranda IA, Döbrössy MD Chronic Deep brain stimulation of the Medial Forebrain Bundle reverses depressive-like behavior in a hemi-parkinsonian rodent model. 2015 Exp Brain Res, volume: 233, issue: 11, page(s): 3073 - 3085
      • Jäger V, Dümpelmann M, LeVan P, Ramantani G, Mader I, Schulze-Bonhage A, Jacobs J Concordance of Epileptic Networks Associated with Epileptic Spikes Measured by High-Density EEG and Fast fMRI. 2015 Plos One, volume: 10, issue: 10, page(s): e0140537
      • Lagzi F, Rotter S Dynamics of Competition between Subnetworks of Spiking Neuronal Networks in the Balanced State. 2015 Plos One, volume: 10, issue: 9, page(s): e0138947
      • Donos C, Dümpelmann M, Schulze-Bonhage A Early Seizure detection Algorithm Based on Intracranial EEG and Random Forest Classification. 2015 Int J Neural Syst, volume: 25, issue: 5, page(s): 1550023
      • S. Stöcklin, A. Yousaf, T. Volk, L.M. Reindl, Efficient Wireless Powering of Biomedical Sensor Systems for Multichannel Brain Implants 2015 IEEE Transactions on Instrumentation and measurement, issue: 99, page(s): 1 - 11
      • Sadeh S, Clopath C, Rotter S Emergence of Functional Specificity in Balanced Networks with Synaptic Plasticity. 2015 Plos Comput Biol, volume: 11, issue: 6, page(s): e1004307
      • Bahuguna J, Aertsen A, Kumar A Existence and Control of Go/No-Go Decision Transition Threshold in the Striatum. 2015 Plos Comput Biol, volume: 11, issue: 4, page(s): e1004233
      • Furlanetti LL, Döbrössy MD, Aranda IA, Coenen VA Feasibility and Safety of Continuous and Chronic Bilateral Deep Brain Stimulation of the Medial Forebrain Bundle in the Naïve Sprague-Dawley Rat. 2015 Behav Neurol, page(s): 256196
      • Winkelmann A, You X, Grünewald N, Haeussler U, Krestel H, Haas CA, Schwarz G, Chen W, Meier J Identification of a new genomic hot spot of evolutionary diversification of protein function 2015 Plos One, volume: 10, issue: 5, page(s): e0125413
      • Sauer JF,, Strüber M,, Bartos M, Impaired fast-spinking interneuron fuinction in a genetic mouse model of depression 2015 Elife
      • C. Boehler, T. Stieglitz, M. Asplund Nanostructured platinum grass enables superior impedance reduction for neural microelectrodes 2015 Biomaterials
        Show abstract Micro-sized electrodes are essential for highly sensitive communication at the neural interface with superior spatial resolution. However, such small electrodes inevitably suffer from high electrical impedance and thus high levels of thermal noise deteriorating the signal to noise ratio. In order to overcome this problem, a nanostructured Pt-coating was introduced as add-on functionalization for impedance reduction of small electrodes. In comparison to platinum black deposition, all used chemicals in the deposition process are free from cytotoxic components. The grass-like nanostructure was found to reduce the impedance by almost two orders of magnitude compared to untreated samples which was lower than what could be achieved with conventional electrode coatings like IrOx or PEDOT. The realization of the Pt-grass coating is performed via a simple electrochemical process which can be applied to virtually any possible electrode type and accordingly shows potential as a universal impedance reduction strategy. Elution tests revealed non-toxicity of the Pt-grass and the coating was found to exhibit strong adhesion to the metallized substrate.
      • Ruther P, Paul O New approaches for CMOS-based devices for large-scale neural recording 2015 ScienceDirect, volume: 32, page(s): 31 - 37
      • Pelz U., Jaklin J., Rostek R., Kroener M, Woias P. Novel Fabrication Process for Micro Thermoelectric Generators (μTEGs) 2015 Journal of Physics: Conference Series, volume: 660, page(s): 012084
        Show abstract A cost effective bottom-up process for the fabrication of micro thermoelectric generators (μTEGs) was developed. It is based on a novel fabrication method involving a selectively sacrificial photoresist for the sequential galvanostatic electrodeposition of thermoelectric materials. The use of an industrial pick and placer (P&P) for dispensing the second photoresist allows for accurate and flexible μTEG designs. The process makes use of Ordyl® as a negative dry film photoresist template and sequential lamination steps for shaping all thermoelectric legs and contacts. All structures of the μTEG are generated in one photoresist multi-layer - this represents the most significant advantage of the process. The process uses a minimum of clean room processing for the preparation of pre-structured substrates for electrodeposition and therefore provides a cost-effective, highly flexible fabrication platform for research and development.
      • Sadeh S, Rotter S Orientation selectivity in inhibition-dominated networks of spiking neurons: effect of single neuron properties and network dynamics. 2015 Plos Comput Biol, volume: 11, issue: 1, page(s): e1004045
      • Elgueta C,, Köhler J,, Bartos M Persistent discharges in dentate gyrus perisonma-inhibiting interneurons require HCN hannel activation 2015 J Neurosci, volume: 35, page(s): 4131 - 4139
      • Kaller CP, Reisert M, Katzev M, Umarova R, Mader I, Hennig J, Weiller C, Kostering L Predicting planning performance from structural connectivity between left and right mid-dorsolateral prefrontal cortex: moderating effects of age during postadolescence and midadulthood. 2015 Cereb Cortex, volume: 25, issue: 4, page(s): 869 - 883
      • Beume LA, Kaller CP, Hoeren M, Kloppel S, Kuemmerer D, Glauche V, Kostering L, Mader I, Rijntjes M, Weiller C, Umarova R Processing of bilateral versus unilateral conditions: evidence for the functional contribution of the ventral attention network. 2015 Cortex, volume: 66, page(s): 91 - 102
      • Sadeh S, Clopath C, Rotter S Processing of Feature Selectivity in Cortical Networks with Specific Connectivity. 2015 Plos One, volume: 10, issue: 6, page(s): e0127547
      • Abdo N, Stachniss C, Spinello L, Burgard W Robot, Organize my Shelves! Tidying up Objects by Predicting User Preferences 2015 Proceedings of the IEEE International Conference on Robotics and Automation (ICRA)
        Show abstract As service robots become more and more capable of performing useful tasks for us, there is a growing need to teach robots how we expect them to carry out these tasks. However, learning our preferences is a nontrivial problem, as many of them stem from a variety of factors including personal taste, cultural background, or common sense. Obviously, such factors are hard to formulate or model a priori. In this paper, we present a solution for tidying up objects in containers, e.g., shelves or boxes, by following user preferences. We learn the user preferences using collaborative filtering based on crowdsourced and mined data. First, we predict pairwise object preferences of the user. Then, we subdivide the objects in containers by modeling a spectral clustering problem. Our solution is easy to update, does not require complex modeling, and improves with the amount of user data. We evaluate our approach using crowdsoucing data from over 1,200 users and demonstrate its effectiveness for two tidy-up scenarios. Additionally, we show that a real robot can reliably predict user preferences using our approach.
      • Bujan AF, Aertsen A, Kumar A Role of input correlations in shaping the variability and noise correlations of evoked activity in the neocortex. 2015 J Neurosci, volume: 35, issue: 22, page(s): 8611 - 8625
      • Castaño-Candamil Sebastián, Höhne Johannes, Martínez-Vargas Juan-David, An Xing-Wei, Castellanos-Domínguez German, Haufe Stefan Solving the EEG inverse problem based on space–time–frequency structured sparsity constraints 2015 Neuroimage, volume: 118, page(s): 598 - 612 Open publication
      • Strüber M, Jonas P, Bartos M Strength and duration of perisomatic GABAergic inhibition depend on distance betweensynaptically connected cells 2015 P Natl Acad Sci Usa, volume: 111, page(s): 13211 - 13216
      • Kostering L, Nitschke K, Schumacher FK, Weiller C, Kaller CP Test-Retest Reliability of the Tower of London Planning Task (TOL-F). 2015 Psychol Assessment, volume: 27, issue: 3, page(s): 925 - 931
      • Kirch RD, Pinnell R, Christ O, Hofmann UG, Cassell J-C The Double-H Maze: A Robust Behavioral Test for Learning and Memory in Rodents 2015 Jove-j Vis Exp, volume: 101, page(s): e52667
      • Vry MS, Tritschler LC, Hamzei F, Rijntjes M, Kaller CP, Hoeren M, Umarova R, Glauche V, Hermsdoerfer J, Goldenberg G, Hennig J, Weiller C The ventral fiber pathway for pantomime of object use. 2015 Neuroimage, volume: 106, page(s): 252 - 263
      • Müller-Putz Gernot R, Leeb Robert, Tangermann Michael, Höhne Johannes, Kübler Andrea, Cincotti Febo, Mattia Donatella, Rupp Rüdiger, Müller Klaus-Robert, Millán José del R Towards Non-Invasive Hybrid Brain-Computer Interfaces: Framework, Practice, Clinical Application and Beyond 2015 P Ieee, volume: 103, issue: 6, page(s): 926 - 943 Open publication
      • Ernst Moritz Hahn, Holger Hermanns, Ralf Wimmer, Bernd Becker Transient Reward Approximation for Continuous-Time Markov Chains 2015 Ieee T Reliab, volume: 64, issue: 4
        Show abstract We are interested in the analysis of very large continuous-time Markov chains (CTMCs) with many distinct rates. Such models arise naturally in the context of the reliability analysis, e.g., of computer networks performability analysis, of power grids, of computer virus vulnerability, and in the study of crowd dynamics. We use abstraction techniques together with novel algorithms for the computation of bounds on the expected final and accumulated rewards in continuous-time Markov decision processes (CTMDPs). These ingredients are combined in a partly symbolic and partly explicit (symblicit) analysis approach. In particular, we circumvent the use of multi-terminal decision diagrams, because the latter do not work well if facing a large number of different rates. We demonstrate the practical applicability and efficiency of the approach on two case studies.
      • Christ O, Hofmann UG Video tracking of swimming rodents on a reflective water surface 2015 Current Directions in Biomedical Engineering, volume: 1, issue: 1, page(s): 232 - 235
        Show abstract Animal models are an essential testbed for new devices on their path from the bench to the patient. Po- tential impairments by brain stimulation are often investi- gated in water mazes to study spatial memory and learn- ing. Video camera based tracking systems exist to quan- tify rodent behaviour, but reflections of ambient light- ing on the water surface and artefacts due to the waves caused by the swimming animal cause errors. This often requires tweaking of algorithms and parameters, or even potentially modifying the lab setup. In the following, we provide a simple solution to alleviate these problem using a combination of region based tracking and independent multimodal background subtraction (IMBS) without having to tweak a plethora of parameters.
    • 2014

      • Lagzi F, Rotter S A Markov model for the temporal dynamics of balanced random networks of finite size. 2014 Front Comput Neurosc, volume: 8, page(s): 142
      • M. Asplund, C. Boehler, T. Stieglitz Anti-inflammatory polymer electrodes for glial scar treatment: bringing the conceptual idea to future results. 2014 Front Neuroeng, volume: 7, page(s): 9
        Show abstract Conducting polymer films offer a convenient route for the functionalization of implantable microelectrodes without compromising their performance as excellent recording units. A micron thick coating, deposited on the surface of a regular metallic electrode, can elute anti-inflammatory drugs for the treatment of glial scarring as well as growth factors for the support of surrounding neurons. Electro-activation of the polymer drives the release of the substance and should ideally provide a reliable method for controlling quantity and timing of release. Driving signals in the form of a constant potential (CP), a slow redox sweep or a fast pulse are all represented in literature. Few studies present such release in vivo from actual recording and stimulating microelectronic devices. It is essential to bridge the gap between studies based on release in vitro, and the intended application, which would mean release into living and highly delicate tissue. In the biological setting, signals are limited both by available electronics and by the biological safety. Driving signals must not be harmful to tissue and also not activate the tissue in an uncontrolled manner. This review aims at shedding more light on how to select appropriate driving parameters for the polymer electrodes for the in vivo setting. It brings together information regarding activation thresholds for neurons, as well as injury thresholds, and puts this into context with what is known about efficient driving of release from conducting polymer films.
      • Umarova RM, Reisert M, Beier TU, Kiselev VG, Kloppel S, Kaller CP, Glauche V, Mader I, Beume L, Hennig J, Weiller C Attention-network specific alterations of structural connectivity in the undamaged white matter in acute neglect. 2014 Hum Brain Mapp, volume: 35, issue: 9, page(s): 4678 - 4692
      • Winkelmann A, Maggio N, Eller J, Caliskan G, Semtner M, Häussler U, Jüttner R, Dugladze T, Smolinsky B, Kowalczyk S, Chronowska E, Schwarz G, Rathjen FG, Rechavi G, Haas CA, Kulik A, Gloveli T, Heinemann U, Meier JC Changes in neural network homeostasis trigger neuropsychiatric symptoms. 2014 J Clin Invest, volume: 124, issue: 2, page(s): 696 - 711
      • Hahn G, Bujan AF, Fregnac Y, Aertsen A, Kumar A Communication through Resonance in Spiking Neuronal Networks. 2014 Plos Comput Biol, volume: 10, issue: 8, page(s): e1003811
        Show abstract The cortex processes stimuli through a distributed network of specialized brain areas. This processing requires mechanisms that can route neuronal activity across weakly connected cortical regions. Routing models proposed thus far are either limited to propagation of spiking activity across strongly connected networks or require distinct mechanisms that create local oscillations and establish their coherence between distant cortical areas. Here, we propose a novel mechanism which explains how synchronous spiking activity propagates across weakly connected brain areas supported by oscillations. In our model, oscillatory activity unleashes network resonance that amplifies feeble synchronous signals and promotes their propagation along weak connections ("communication through resonance"). The emergence of coherent oscillations is a natural consequence of synchronous activity propagation and therefore the assumption of different mechanisms that create oscillations and provide coherence is not necessary. Moreover, the phase-locking of oscillations is a side effect of communication rather than its requirement. Finally, we show how the state of ongoing activity could affect the communication through resonance and propose that modulations of the ongoing activity state could influence information processing in distributed cortical networks.
        Open publication
      • Sadeh S, Rotter S Distribution of Orientation Selectivity in Recurrent Networks of Spiking Neurons with Different Random Topologies 2014 Plos One Open publication
      • Puig MV, Rose J, Schmidt R, Freund N Dopamine modulation of learning and memory in the prefrontal cortex: insights from studies in primates, rodents, and birds. 2014 Front Neural Circuit, volume: 8, page(s): 93 Open publication
      • Chai X*, Münzner G*, Zhao S, Tinnes S, Kowalski J, Häussler U, Young C, Haas CA*, Frotscher M* Epilepsy-induced motility of differentiated neurons 2014 Cereb Cortex, volume: 24, page(s): 2130 - 2140
      • Somerlik K H, Stieglitz T, Schulze-Bonhage A Evaluation von Parametern zur Hirnstimulation 2014 Zeitschrift für Epileptologie, volume: 27, page(s): 7 - 18
      • Jacobs J, Stich J, Zahneisen B, Assländer J, Ramantani G, Schulze-Bonhage A, Korinthenberg R, Hennig J, LeVan P Fast fMRI provides high statistical power in the analysis of epileptic networks. 2014 NeuroImage, volume: 88, page(s): 282 - 294
        Show abstract EEG-fMRI is a unique method to combine the high temporal resolution of EEG with the high spatial resolution of MRI to study generators of intrinsic brain signals such as sleep grapho-elements or epileptic spikes. While the standard EPI sequence in fMRI experiments has a temporal resolution of around 2.5-3s a newly established fast fMRI sequence called MREG (Magnetic-Resonance-Encephalography) provides a temporal resolution of around 100ms. This technical novelty promises to improve statistics, facilitate correction of physiological artifacts and improve the understanding of epileptic networks in fMRI. The present study compares simultaneous EEG-EPI and EEG-MREG analyzing epileptic spikes to determine the yield of fast MRI in the analysis of intrinsic brain signals. Patients with frequent interictal spikes (>3/20min) underwent EEG-MREG and EEG-EPI (3T, 20min each, voxel size 3×3×3mm, EPI TR=2.61s, MREG TR=0.1s). Timings of the spikes were used in an event-related analysis to generate activation maps of t-statistics. (FMRISTAT, |t|>3.5, cluster size: 7 voxels, p<0.05 corrected). For both sequences, the amplitude and location of significant BOLD activations were compared with the spike topography. 13 patients were recorded and 33 different spike types could be analyzed. Peak T-values were significantly higher in MREG than in EPI (p<0.0001). Positive BOLD effects correlating with the spike topography were found in 8/29 spike types using the EPI and in 22/33 spikes types using the MREG sequence. Negative BOLD responses in the default mode network could be observed in 3/29 spike types with the EPI and in 19/33 with the MREG sequence. With the latter method, BOLD changes were observed even when few spikes occurred during the investigation. Simultaneous EEG-MREG thus is possible with good EEG quality and shows higher sensitivity in regard to the localization of spike-related BOLD responses than EEG-EPI. The development of new methods of analysis for this sequence such as modeling of physiological noise, temporal analysis of the BOLD signal and defining appropriate thresholds is required to fully profit from its high temporal resolution.
      • Mechling A, Hübner N, Lee HL, Hennig J, von Elverfeldt D, Harsan LA. Fine-grained mapping of mouse brain functional connectivity with resting-state fMRI. 2014 Neuroimage, volume: 96, page(s): 203 - 215
        Show abstract Understanding the intrinsic circuit-level functional organization of the brain has benefited tremendously from the advent of resting-state fMRI (rsfMRI). In humans, resting-state functional network has been consistently mapped and its alterations have been shown to correlate with symptomatology of various neurological or psychiatric disorders. To date, deciphering the mouse brain functional connectivity (MBFC) with rsfMRI remains a largely underexplored research area, despite the plethora of human brain disorders that can be modeled in this specie. To pave the way from pre-clinical to clinical investigations we characterized here the intrinsic architecture of mouse brain functional circuitry, based on rsfMRI data acquired at 7T using the Cryoprobe technology. High-dimensional spatial group independent component analysis demonstrated fine-grained segregation of cortical and subcortical networks into functional clusters, overlapping with high specificity onto anatomical structures, down to single gray matter nuclei. These clusters, showing a high level of stability and reliability in their patterning, formed the input elements for computing the MBFC network using partial correlation and graph theory. Its topological architecture conserved the fundamental characteristics described for the human and rat brain, such as small-worldness and partitioning into functional modules. Our results additionally showed inter-modular interactions via "network hubs". Each major functional system (motor, somatosensory, limbic, visual, autonomic) was found to have representative hubs that might play an important input/output role and form a functional core for information integration. Moreover, the rostro-dorsal hippocampus formed the highest number of relevant connections with other brain areas, highlighting its importance as core structure for MBFC.
      • Derix J, Iljina O, Weiske J, Schulze-Bonhage A, Aertsen A, Ball T From speech to thought: the neuronal basis of cognitive units in non-experimental, real-life communication investigated using ECoG. 2014 Front Hum Neurosci, volume: 8, page(s): 383
        Show abstract Exchange of thoughts by means of expressive speech is fundamental to human communication. However, the neuronal basis of real-life communication in general, and of verbal exchange of ideas in particular, has rarely been studied until now. Here, our aim was to establish an approach for exploring the neuronal processes related to cognitive “idea” units (IUs) in conditions of non-experimental speech production. We investigated whether such units corresponding to single, coherent chunks of speech with syntactically-defined borders, are useful to unravel the neuronal mechanisms underlying real-world human cognition. To this aim, we employed simultaneous electrocorticography (ECoG) and video recordings obtained in pre-neurosurgical diagnostics of epilepsy patients. We transcribed non-experimental, daily hospital conversations, identified IUs in transcriptions of the patients' speech, classified the obtained IUs according to a previously-proposed taxonomy focusing on memory content, and investigated the underlying neuronal activity. In each of our three subjects, we were able to collect a large number of IUs which could be assigned to different functional IU subclasses with a high inter-rater agreement. Robust IU-onset-related changes in spectral magnitude could be observed in high gamma frequencies (70–150 Hz) on the inferior lateral convexity and in the superior temporal cortex regardless of the IU content. A comparison of the topography of these responses with mouth motor and speech areas identified by electrocortical stimulation showed that IUs might be of use for extraoperative mapping of eloquent cortex (average sensitivity: 44.4%, average specificity: 91.1%). High gamma responses specific to memory-related IU subclasses were observed in the inferior parietal and prefrontal regions. IU-based analysis of ECoG recordings during non-experimental communication thus elicits topographically- and functionally-specific effects. We conclude that segmentation of spontaneous real-world speech in linguistically-motivated units is a promising strategy for elucidating the neuronal basis of mental processing during non-experimental communication.
        Open publication
      • Yim MY, Kumar A, Aertsen A, Rotter S Impact of correlated inputs to neurons: modeling observations from in vivo intracellular recordings. 2014 J Comput Neurosci Open publication
      • Xie Y, Martini N, Hassler C, Kirch RD, Stieglitz T, Seifert T, Hofmann UG In vivo monitoring of glial scar proliferation on chronically implanted neural electrodes by fiber optical coherence tomography 2014 Frontiers in Neuroengineering, volume: 7, issue: 34, page(s): 1 - 10
      • Proulx S, Safi-Harb M, Levan P, An D, Watanabe S, Gotman J Increased sensitivity of fast BOLD fMRI with a subject-specific hemodynamic response function and application to epilepsy. 2014 Neuroimage, volume: 93, issue: 1, page(s): 59 - 73
        Show abstract Activation detection in functional Magnetic Resonance Imaging (fMRI) typically assumes the hemodynamic response to neuronal activity to be invariant across brain regions and subjects. Reports of substantial variability of the morphology of blood-oxygenation-level-dependent (BOLD) responses are accumulating, suggesting that the use of a single generic model of the expected response in general linear model (GLM) analyses does not provide optimal sensitivity due to model misspecification. Relaxing assumptions of the model can limit the impact of hemodynamic response function (HRF) variability, but at a cost on model parsimony. Alternatively, better specification of the model could be obtained from a priori knowledge of the HRF of a given subject, but the effectiveness of this approach has only been tested on simulation data. Using fast BOLD fMRI, we characterized the variability of hemodynamic responses to a simple event-related auditory-motor task, as well as its effect on activation detection with GLM analyses. We show the variability to be higher between subjects than between regions and variation in different regions to correlate from one subject to the other. Accounting for subject-related variability by deriving subject-specific models from responses to the task in some regions lead to more sensitive detection of responses in other regions. We applied the approach to epilepsy patients, where task-derived patient-specific models provided additional information compared to the use of a generic model for the detection of BOLD responses to epileptiform activity identified on scalp electro-encephalogram (EEG). This work highlights the importance of improving the accuracy of the model for detecting neuronal activation with fMRI, and the fact that it can be done at no cost to model parsimony through the acquisition of independent a priori information about the hemodynamic response.
      • Kindermans Pieter-Jan, Tangermann Michael, Müller Klaus-Robert, Schrauwen Benjamin Integrating dynamic stopping, transfer learning and language models in an adaptive zero-training ERP speller 2014 J Neural Eng, volume: 11, issue: 3
        Show abstract Objective. Most BCIs have to undergo a calibration session in which data is recorded to train decoders with machine learning. Only recently zero-training methods have become a subject of study. This work proposes a probabilistic framework for BCI applications which exploit event-related potentials (ERPs). For the example of a visual P300 speller we show how the framework harvests the structure suitable to solve the decoding task by (a) transfer learning, (b) unsupervised adaptation, (c) language model and (d) dynamic stopping. Approach. A simulation study compares the proposed probabilistic zero framework (using transfer learning and task structure) to a state-of-the-art supervised model on n = 22 subjects. The individual influence of the involved components (a)–(d) are investigated. Main results. Without any need for a calibration session, the probabilistic zero-training framework with inter-subject transfer learning shows excellent performance—competitive to a state-of-the-art supervised method using calibration. Its decoding quality is carried mainly by the effect of transfer learning in combination with continuous unsupervised adaptation. Significance. A high-performing zero-training BCI is within reach for one of the most popular BCI paradigms: ERP spelling. Recording calibration data for a supervised BCI would require valuable time which is lost for spelling. The time spent on calibration would allow a novel user to spell 29 symbols with our unsupervised approach. It could be of use for various clinical and non-clinical ERP-applications of BCI.
      • Hainmüller T, Krieglstein K, Kulik A, Bartos M Joint CP-AMPA and group l mGlu receptor activation is required for synaptic plasticity in dentate gyrus fast-spiking interneurons. 2014 P Natl Acad Sci Usa, volume: 111, issue: 36, page(s): 13211 - 13216
      • Wapler M, Leupold J, Dragonu I, von Elverfeld D, Zaitsev M, Wallrabe U Magnetic properties of materials for MR engineering, micro-MR and beyond 2014 J Magn Reson, volume: 242C, page(s): 233 - 242
      • Gierthmuehlen M, Wang X, Gkogkidis A, Henle C, Fischer J, Fehrenbacher T, Kohler F, Raab M, Mader I, Kuehn C, Foerster K, Haberstroh J, Freiman TM, Stieglitz T, Rickert J, Schuettler M, Ball T Mapping of sheep sensory cortex with a novel microelectrocorticography grid. 2014 J Comp Neurol, volume: 522, issue: 16, page(s): 3590 - 3608
      • Höhne Johannes, Holz Elisa, Staiger-Sälzer Pit, Müller Klaus-Robert, Kübler Andrea, Tangermann Michael Motor Imagery for Severely Motor-Impaired Patients: Evidence for Brain-Computer Interfacing as Superior Control Solution 2014 PLoS ONE, volume: 9, issue: 8, page(s): e104854
        Show abstract Brain-Computer Interfaces (BCIs) strive to decode brain signals into control commands for severely handicapped people with no means of muscular control. These potential users of noninvasive BCIs display a large range of physical and mental conditions. Prior studies have shown the general applicability of BCI with patients, with the conflict of either using many training sessions or studying only moderately restricted patients. We present a BCI system designed to establish external control for severely motor-impaired patients within a very short time. Within only six experimental sessions, three out of four patients were able to gain significant control over the BCI, which was based on motor imagery or attempted execution. For the most affected patient, we found evidence that the BCI could outperform the best assistive technology (AT) of the patient in terms of control accuracy, reaction time and information transfer rate. We credit this success to the applied user-centered design approach and to a highly flexible technical setup. State-of-the art machine learning methods allowed the exploitation and combination of multiple relevant features contained in the EEG, which rapidly enabled the patients to gain substantial BCI control. Thus, we could show the feasibility of a flexible and tailorable BCI application in severely disabled users. This can be considered a significant success for two reasons: Firstly, the results were obtained within a short period of time, matching the tight clinical requirements. Secondly, the participating patients showed, compared to most other studies, very severe communication deficits. They were dependent on everyday use of AT and two patients were in a locked-in state. For the most affected patient a reliable communication was rarely possible with existing AT.
      • Jacobs J, Menzel A, Ramantani G, Korbl K, Asslander J, Schulze-Bonhage A, Hennig J, LeVan P Negative BOLD in default-mode structures measured with EEG-MREG is larger in temporal than extra-temporal epileptic spikes. 2014 Front Neurosci, volume: 8, page(s): 335
      • Hoeren M, Kummerer D, Bormann T, Beume L, Ludwig VM, Vry MS, Mader I, Rijntjes M, Kaller CP, Weiller C Neural bases of imitation and pantomime in acute stroke patients: distinct streams for praxis. 2014 Brain, volume: 137, issue: Pt 10, page(s): 2796 - 2810
      • Stieglitz T, Neves H, Ruther P Neural probes-microsystems to interface with the brain. 2014 Biomed Tech, volume: 59, issue: 4, page(s): 269 - 271
      • Gittis AH, Berke JD, Bevan MD, Chan CS, Mallet N, Morrow MM, Schmidt R New roles for the external globus pallidus in Basal Ganglia circuits and behavior. 2014 J Neurosci, volume: 34, issue: 46, page(s): 15178 - 15183
      • Asplund M, Boehler C, Heizmann S, Egert U, Hoffmann U, Stieglitz T Polymer electrodes for drug release during stimulation 2014 Biomed Eng-biomed Te, volume: 59, page(s): S1076
      • Volk T, Gorbey S, Grunwald W, Bhattacharyya M, Lemmer B, Reindl L, Stieglitz T, Jansen D RFID Technology for Continuous Monitoring of Physiological Signals in Small Animals. 2014 Ieee T Bio-med Eng, volume: 62, issue: 2, page(s): 618 - 626
      • Winkler Irene, Brandl Stephanie, Horn Franziska, Waldburger Eric, Allefeld Carsten, Tangermann Michael Robust artifactual independent component classification for BCI practitioners 2014 Journal of Neural Engineering, volume: 11, issue: 3
        Show abstract Objective. EEG artifacts of non-neural origin can be separated from neural signals by independent component analysis (ICA). It is unclear (1) how robustly recently proposed artifact classifiers transfer to novel users, novel paradigms or changed electrode setups, and (2) how artifact cleaning by a machine learning classifier impacts the performance of brain–computer interfaces (BCIs). Approach . Addressing (1), the robustness of different strategies with respect to the transfer between paradigms and electrode setups of a recently proposed classifier is investigated on offline data from 35 users and 3 EEG paradigms, which contain 6303 expert-labeled components from two ICA and preprocessing variants. Addressing (2), the effect of artifact removal on single-trial BCI classification is estimated on BCI trials from 101 users and 3 paradigms. Main results . We show that (1) the proposed artifact classifier generalizes to completely different EEG paradigms. To obtain similar results under massively reduced electrode setups, a proposed novel str
      • Reinhard M, Schumacher FK, Rutsch S, Oeinck M, Timmer J, Mader I, Schelter B, Weiller C, Kaller CP Spatial mapping of dynamic cerebral autoregulation by multichannel near-infrared spectroscopy in high-grade carotid artery disease. 2014 J Biomed Opt, volume: 19, issue: 9, page(s): 97005
      • Savanthrapadian S, Meyer T, Elgueta C, Booker S, Vida I, Bartos M Synaptic Properties of SOM- and CCK-Expressing Cells in Dentate Gyrus Interneuron Networks. 2014 J Neurosci, volume: 34, page(s): 8197 - 8209
      • Duempelmann M,, Jacobs J, Schulze-Bonhage A Temporal and spatial characteristics of high frequency oscillations as a new biomarker in epilepsy 2014 Epilepsia
      • Höhne Johannes, Tangermann Michael Towards User-friendly Spelling with an Auditory Brain-Computer Interface: The CharStreamer Paradigm 2014 PLoS ONE, volume: 9, issue: 6, page(s): e98322
      • Heinze K, Ruh N, Nitschke K, Reis J, Fritsch B, Unterrainer JM, Rahm B, Weiller C, Kaller CP Transcranial direct current stimulation over left and right DLPFC: Lateralized effects on planning performance and related eye movements. 2014 Biol Psychol, volume: 102, page(s): 130 - 140
      • Kindermans Pieter-Jan, Schreuder Martijn, Schrauwen Benjamin, Müller Klaus-Robert, Tangermann Michael True Zero-Training Brain-Computer Interfacing - An Online Study 2014 PLoS ONE, volume: 9, issue: 7, page(s): e102504
        Show abstract Despite several approaches to realize subject-to-subject transfer of pre-trained classifiers, the full performance of a Brain-Computer Interface (BCI) for a novel user can only be reached by presenting the BCI system with data from the novel user. In typical state-of-the-art BCI systems with a supervised classifier, the labeled data is collected during a calibration recording, in which the user is asked to perform a specific task. Based on the known labels of this recording, the BCI’s classifier can learn to decode the individual’s brain signals. Unfortunately, this calibration recording consumes valuable time. Furthermore, it is unproductive with respect to the final BCI application, e.g. text entry. Therefore, the calibration period must be reduced to a minimum, which is especially important for patients with a limited concentration ability. The main contribution of this manuscript is an online study on unsupervised learning in an auditory event-related potential (ERP) paradigm. Our results demonstrate that the calibration recording can be bypassed by utilizing an unsupervised trained classifier, that is initialized randomly and updated during usage. Initially, the unsupervised classifier tends to make decoding mistakes, as the classifier might not have seen enough data to build a reliable model. Using a constant re-analysis of the previously spelled symbols, these initially misspelled symbols can be rectified posthoc when the classifier has learned to decode the signals. We compare the spelling performance of our unsupervised approach and of the unsupervised posthoc approach to the standard supervised calibration-based dogma for n = 10 healthy users. To assess the learning behavior of our approach, it is unsupervised trained from scratch three times per user. Even with the relatively low SNR of an auditory ERP paradigm, the results show that after a limited number of trials (30 trials), the unsupervised approach performs comparably to a classic supervised model.
      • Derix J, Yang S, Lusebrink F, Fiederer LD, Schulze-Bonhage A, Aertsen A, Speck O, Ball T Visualization of the amygdalo-hippocampal border and its structural variability by 7T and 3T magnetic resonance imaging. 2014 Hum Brain Mapp, volume: 35, issue: 9, page(s): 4316 - 4329
      • Grah G, Kumar A Wettstreit der ­Metaphern 2014 Gehirn und Geist, volume: 13, issue: 7, page(s): 60 - 65
        Show abstract Mit bildhaften Vergleichen versuchen Philosophen und Wissenschaftler seit der Antike, die Arbeits­weise des menschlichen Gehirns zu beschreiben. Diese Metaphern sind Kinder ihrer jeweiligen Zeit. Sie spiegeln den aktuellen Stand der Technik wider und prägen somit die Vorstellung vom menschlichen Geist. Die Begriffsschablonen können helfen, die Komplexität des Gehirns besser zu verstehen. Indem sie eine bestimmte Eigenschaft hervorheben, unter­schlagen sie allerdings andere Aspekte, die für das Verständnis ebenso wichtig sein könnten.
      • Mutschler I, Wieckhorst B, Meyer AH, Schweizer T, Klarhofer M, Wilhelm FH, Seifritz E, Ball T Who gets afraid in the MRI-scanner? Neurogenetics of state-anxiety changes during an fMRI experiment. 2014 Neurosci Lett, volume: 583, page(s): 81 - 86
      • Kaller CP, Loosli SV, Rahm B, Gossel A, Schieting S, Hornig T, Hennig J, Tebartz van Elst L, Weiller C, Katzev M Working memory in schizophrenia: behavioral and neural evidence for reduced susceptibility to item-specific proactive interference. 2014 Biol Psychiat, volume: 76, issue: 6, page(s): 486 - 494
      • Huggins Jane, Guger Christoph, Allison Brendan, Anderson Charles, Batista Aaron, Brouwer Anne-Marie, Brunner Clemens, Chavarriaga Ricardo, Fried-Oken Melanie, Gunduz Aysegul, Gupta Disha, Kübler Andrea, Leeb Robert, Lotte Fabien, Miller Lee, Müller-Putz G Workshops of the fifth international brain-computer interface meeting: Defining the future 2014 Brain-Computer Interfaces, volume: 1, issue: 1, page(s): 27 - 49
    • 2013

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  • Reviews 5

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  • Book chapters 3

    • 2015

    • 2014

      • Stieglitz T, Hofman U, Rosahl S K Neurotechnik 2014 Walter de Gruyter, page(s): 441 - 466
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  • Talks 61

    • 2017

      • Stieglitz T Is this me ? Interfaces with the nervous system control prostheses and treat diseases and disorders 2017
      • Stieglitz T Why Neurotechnologies? About the Purposes for Developing Clinical Applications of Neurotechnologies 2017
    • 2016

      • M Kuhl Achievements and trends of CMOS-assisted neural recording interfaces 2016
      • Boehler C, Kleber C, Martini N, Xie Y, Hofmann U G, Stieglitz T, Asplund M Anti-inflammatory coatings on flexible neural probes in the cortex: A chronic in vivo study 2016
      • M Kuhl, M Rajabzadeh Bio-potential pre-amplifiers with reduced transistor count for optimized area and NEF efficiency 2016
      • M Kuhl CMOS Electronics for Implantable Neural Interface 2016
      • Stieglitz T Different Applications but Similar Technologies and Same Challenges in Neural Implants 2016
      • Boehler C, Stieglitz T, Asplund M Nanostructured platinum – a competitive material for neural stimulation and recording 2016
      • Stieglitz T Thin-film electrodes to interface with the nervous system 2016
    • 2015

      • Haas CA A mesial temporal lobe epilepsy model as test system for neuroprotective strategies against epilepsy-related brain damage. 2015
      • Clausen, J, Stieglitz, T Darf Technik den Nerv treffen? - Ein Streitgespräch 2015
      • R. Schmidt Dynamics of basal ganglia circuits during movement initiation and suppression 2015
      • Leicht J, Amayreh M, Moranz C, Maurath D, Willmann A, Hehn T, Manoli Y Electromagnetic Vibration Energy Harvester Interface IC with Conduction-angle-controlled Maximum-power-point Tracking and Harvesting Efficiencies of up to 90% 2015
      • Kuhl M, Keller M, Muller N, Shui B, Mohamed S, Cota O, Rossbach D, Taschwer A, Manoli Y Entwurf neuronaler Schnittstellenschaltungen – Mikroelektronik im Exzellenzcluster BrainLinks-BrainTools 2015
      • Haas CA Imaging epileptogenesis in mice. 2015
      • Stieglitz T, Ordonez, J.S, Hassler, C, Fiedler, E, Ashouri, D, Kohler, F, Boretius, T, Boehler, C, Asplund, M, Ball, T, Rickert, J, Cvancara, P, Schuettler, M Intelligente Implantate Chancen und Herausforderungen am Beispiel neuro-technischer Anwendungen 2015
      • Stieglitz T, Ordonez, J.S, Hassler, C, Fiedler, E, Ashouri, D, Kohler, F, Boretius, T, Boehler, C, Asplund, M, Ball, T, Rickert, J, Cvancara, P, Schuettler, M Mikrosysteme im Kontakt mit dem Nervensystem - Chancen und Herausforderungen 2015
      • Schwärzle M, Elmlinger P, Paul O, Ruther P Miniaturisiertes 3×3 LED-Array mit integrierten Glasfasern und hochflexiblem Flachbandkabel für Anwendungen in der Optogenetik 2015
      • Stieglitz T, Ordonez, J.S, Hassler, C, Fiedler, E, Ashouri, D, Kohler, F, Boretius, T, Boehler, C, Asplund, M, Ball, T, Rickert, J, Cvancara, P, Schuettler, M Neurotechnische Implantate im peripheren und zentralen Nervensystem 2015
      • Haas CA On the search for biomarkers: imaging epileptogenesis with high resolution. 2015
      • Stieglitz T, Ordonez, J.S, Hassler, C, Fiedler, E, Ashouri, D, Kohler, F, Boretius, T, Boehler, C, Asplund, M, Ball, T, Rickert, J, Cvancara, P, Schuettler, M Sensorik in der Medizintechnik am Beispiel neurotechnischer Implantate 2015
      • Stieglitz T Strom hilft heilen – Neurotechnik in Therapie und Rehabilitation 2015
      • Häussler U The hippocampal CA2 region in temporal lobe epilepsy. 2015
    • 2014

      • Mottaghi S, Helgason T, Hofmann UG A scalable multi-channel modular electrical stimulator for therapeutic field steering 2014
      • Manuel Blum, Sam Ewing, Raimar Rosteck, Peter Woias, Martin Riedmiller, Andreas Schulze-Bonhage, Matthias Dümpelmann Automatic seizure detection for closed loop devices by simple time domain features and machine learning methods 2014
      • Sherif M, Ortmanns M Basics, Regulations and Implementation of Data Telemetry for Implants 2014
      • Braig, Moritz Cardiac Mouse MRI. 2014
      • Hofmann UG Challenges on the path to a bidirectional brain-machine interface 2014
      • Hazrati, MK, Almajidy, R, Oung, S, Hofmann UG Controlling a simple hand prosthesis using brain signals 2014
      • Weichwald S, Meyer T, Schölkopf B, Ball T, Grosse-Wentrup M Decoding Index Finger Position From EEG Using Random Forests. 2014
      • C. Boehler, S. Heizmann, C. Kleber, A. Schopf, T. Stieglitz, M. Asplund Electroactive Functionalized Coatings: The next generation of PEDOT microelectrode systems 2014
      • Stieglitz, T Fühlende Prothesen - von der Prothetik zur Neuroprothetik. 2014
      • Hofmann UG Interfacing the brain - On the path to a bidirectional brain-machine interface 2014
      • Stieglitz T, Ordonez, J.S, Henle, C, Meier, W, Hassler, C, Fiedler, E, Kohler, F, Boretius, T, Boehler, C, Asplund, M, Ball, T, Rickert, J, Cvancara, P, Schuettler, M Miniaturized neural interfaces and implants in fundamental and translational research 2014
      • Stieglitz, T, Ordonez, J.S, Henle, C, Meier, W, Hassler, C, Fiedler, E, Kohler, F, Boretius, T, Boehler, C, Asplund, M, Schuettler, M Miniaturized Neural Interfaces and Implants in Neurological Rehabilitation 2014
      • Stieglitz, T, Plachta, D.T.T., Giertmuehlen, M, Boretius, T, Rubehn, B, Henle, C, Meier, W, Kohler, F, Fiedler, E, Hassler, C, Ordonez, J.S, Rickert, J, Zentner, J, Schuettler, M Neural Prostheses- today and tomorrow 2014
      • Stieglitz T Neuroimplantate-Technische Systeme an der Material-Gewebe-Schnittstelle 2014
      • Stieglitz T Neurotechnische Mensch-Maschine Schnittstellen -Fiktion oder klinische Praxis? 2014
      • Xie Y, Martini N, Hassler C, Kirch RD, Stieglitz T, Hofmann UG Online monitoring of neuroinflammation induced by chronic implanted microelectrode using a fiber-based OCT 2014
      • Boehler C, Stieglitz T, Asplund M Platinum Nano-Grass: Add-On Functionalization for Implantable Microelectrodes. 2014
      • Heizmann S, Kilias A, Ringwald P, Okujeni S, Boehler C, Ruther P, Egert U, Asplund M Precise labeling of microelectrode positions by accurate neuronal tracing based on pedot-dye coatings 2014
      • Asplund M, Schopf A, Boehler C The Electrochemistry of In-Vitro Electrotaxis: How and What to Measure? 2014
      • Stieglitz, T Vom Impuls zur Neuromodulation 2014
    • 2013

      • Gierthmuehlen M, Wang X, Freiman T, Haberstroh J, Rickert J, Schuettler M, Ball T A chronic animal model for the functional evaluation of a fully implantable mECoG-based brain-machine interfacing device 2013
      • Stieglitz, T, Giertmuehlen, M, Cota, O, Plachta, D.T.T Ansätze zur personalisierten Baroreflex-Stimulation 2013
      • Haas CA Brain Research for Epilepsy: From Man to Mice 2013
      • Boehler C, Stieglitz T, Asplund M Design and evaluation of PEDOT:Dex based drug delivery coatings for neural implant electrodes. 2013
      • Stieglitz T, Rubehn B, Henle C, Meier W, Kohler F, Fiedler E, Ordonez J, Schuettler M ECoG Electrodes 2013
      • Stieglitz T, Rubehn B, Boretius T, Henle C, Ordonez J, Meier W, Hassler C, Boehler C, Kohler F, Schuettler M Electrodes and Implants for the Central Nervous System 2013
      • Haas CA Epilepsy Research: a Story of Mice and Men 2013
      • Stieglitz T, Rubehn B, Boretius T, Henle C, Meier W, Kohler F, Fiedler E, Ordonez J, Rickert J, Schuettler M Flexible Neural Probes in Fundamental and Translational Research 2013
      • Stieglitz T, Henle C, Meier W, Kohler F, Ordonez J, Rickert J, Schuettler M From Prototypes to Approved Devices: Challenges to Setup a Production 2013
      • Stieglitz T, Boretius T, Ordonez J, Boehler C, Schuettler M Intelligente Implantate 2013
      • Stieglitz T, Rubehn B, Boretius T, Henle C, Ordonez J, Meier W, Hassler C, Boehler C, Kohler F, Schuettler M Microtechnologies for Neural Implants 2013
      • Stieglitz T Miniaturized Neural Interfaces and Implants 2013
      • Stieglitz T, Rubehn B, Boretius T, Henle C, Ordonez J, Meier W, Hassler C, Boehler C, Kohler F, Schuettler M Miniaturized Neural Interfaces and Implants in Basic and Translational Research 2013
      • Stieglitz T, Rubehn B, Boretius T, Henle C, Ordonez J, Meier W, Hassler C, Boehler C, Kohler F, Schuettler M Neural Interfaces for Research Applications 2013
      • Haas CA Neurogenesis in temporal lobe epilepsy 2013
      • Häussler U, Bielefeld L, Wolfart J, Haas CA Neurogenesis in the dentate gyrus. Cause of increased epileptogenicity? 2013
      • Stieglitz T, Rubehn B, Boretius T, Ordonez J, Schuettler M Stability and Selectivity of PNS Interfaces 2013
      • Kilias A, Froriep UP, Häussler U, Kumar A, Haas CA, Egert U Sustained phase coupling of single cell firing to network oscillations under epileptic conditions 2013
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  • Conference papers 196

    • 2017

      • J D Rieseler, M Kuhl A Superposition-Based Analog Data Compression Scheme for Massively-Parallel Neural Recordings 2017 IEEE Biomedical Circuits & Systems Conference (BioCAS)
      • Burget F.*, Fiederer L.D.J.*, Kuhner D.*, Völker M.*, Aldinger J., Schirrmeister R.T., Do C., Boedecker J., Nebel B., Ball T., Burgard W. Acting Thoughts: Towards a Mobile Robotic Service Assistant for Users with Limited Communication Skill. 2017 Proceedings of the 2017 IEEE European Conference on Mobile Robotics
      • Hübner David, Tangermann Michael Challenging the assumption that auditory event-related potentials are independent and identically distributed 2017 Proceedings of the 7th International Brain-Computer Interface Meeting 2017: From Vision to Reality, page(s): 192 - 197
      • Castano-Candamil Sebastian, Mottaghi Soheil, Coenen Volker, Hofmann Ulrich, Tangermann Michael Closed-Loop Deep Brain Stimulation System for an Animal Model of Parkinson’s Disease: A Pilot Study 2017 Proceedings of the 7th Graz Brain-Computer Interface Conference (GBCIC 2017), page(s): 58 - 63
      • Welke D, Behncke J, Schirrmeister RT, Hader M, Müller O, Burgard W, Ball T Decoding Brain Responses During Robot-Error Observation. 2017
      • Kolkhorst Henrich, Burgard Wolfram, Tangermann Michael Decoding Hazardous Events in Driving Videos 2017 Proceedings of the 7th Graz Brain-Computer Interface Conference 2017, page(s): 242 - 247
        Show abstract Decoding the human brain state with BCI methods can be seen as a building block for human-machine interaction, providing a noisy but objective, low-latency information channel including human reactions to the environment. Specifically in the context of autonomous driving, human judgement is relevant in high-level scene understanding. Despite advances in computer vision and scene understanding, it is still challenging to go from the detection of traffic events to the detection of hazards. We present a preliminary study on hazard perception, implemented in the context of natural driving videos. These have been augmented with artificial events to create potentially hazardous driving situations. We decode brain signals from electroencephalography (EEG) in order to classify single events into hazardous and non-hazardous ones. We find that event-related responses can be discriminated and the classification of events yields an AUC of 0.79. We see these results as a step towards incorporating EEG feedback into more complex, real-world tasks.
      • Kolkhorst Henrich, Tangermann Michael, Burgard Wolfram Decoding Perceived Hazardousness from User’s Brain States to Shape Human-Robot Interaction 2017 Proceedings of the Companion of the 2017 ACM/IEEE International Conference on Human-Robot Interaction, page(s): 349 - 350 Open publication
      • J Hafner, M Kuhl, M Schwaerzle, T Hehn, D Rossbach, O Paul Fabrication of Planar Copper Microcoils for Telemetric Orthodontic Applications 2017 Proc. Eurosensors Open publication
      • Hübner David, Kindermans Pieter-Jan, Verhoeven Thibault, Tangermann Michael Improving learning from label proportions by reducing the feature dimensionality 2017 Proceedings of the 7th International Brain-Computer Interface Meeting 2017: From Vision to Reality, page(s): 186 - 191
      • Hübner David, Verhoeven Thibault, Kindermans Pieter-Jan, Tangermann Michael Mixing two unsupervised estimators for event-related potential decoding: An online evaluation 2017 Proceedings of the 7th International Brain-Computer Interface Meeting 2017: From Vision to Reality, page(s): 198 - 203
      • Castano-Candamil Sebastian, Tangermann Michael Subspace Decomposition in the Frequency Domain 2017 Proceedings of the 7th Graz Brain-Computer Interface Conference (GBCIC 2017), page(s): 64 - 69
      • Meinel Andreas, Lotte Fabien, Tangermann Michael Tikhonov Regularization Enhances EEG-Based Spatial Filtering For Single-Trial Regression 2017 Proceedings of the 7th Graz Brain-Computer Interface Conference 2017, page(s): 308 - 313
    • 2016

      • Amayreh M, Leicht J, Manoli Y A 200ns Settling Time Fully Integrated Low Power LDO Regulator with Comparators as Transient Enhancement 2016 Proceedings of the IEEE International Symposium on Circuits and Systems (ISCAS), page(s): 494 - 497
      • Butz N, Taschwer A, Manoli Y, Kuhl M A 22V Compliant 56µW Active Charge Balancer Enabling 100% Charge Compensation even in Monophasic and 36% Amplitude Correction in Biphasic Neural Stimulators 2016 Proceedings of the IEEE International Solid-State Circuits Conference (ISSCC), page(s): 390 - 391
      • Schillinger D, Hu Y, Amayreh M, Moranz C, Manoli Y A 96.7% Efficient Boost Converter with a Stand-by Current of 420nA for Energy Harvesting Applications 2016 Proceedings of the IEEE International Symposium on Circuits and Systems (ISCAS), page(s): 654 - 657
      • Mueller M, Boehler C, Jaeger J, Asplund M, Stieglitz T A double-sided fabrication process for intrafascicular parylene C based electrode arrays 2016 Engineering in Medicine and Biology Society, page(s): 2798 - 2801
        Show abstract After the development of a single-sided fabrication process for intrafascicular parylene C based electrode arrays tests showed that an increase in integration density can only be achieved by a double-side process. The process uses 25 μm thick platinum iridium foil, which is thinned down with the laser and sandwiched between two 10 μm thick parylene C layers. Utilizing a picosecond laser (355 nm Nd:YVO4) it was possible to fabricate 40 μm thick electrodes that can be implanted directly in the nerve without relying on additional support layers like chitosan or silk. The fabricated samples feature three 80 μm diameter electrodes on each side and a large ground electrode that is opened to both sides. Impedance mismatches from front to back side as a result of the fabrication process are compensated by electrochemical deposition of nanostructured platinum. This step makes it possible to bring the impedances of the small electrodes down to the range of just a few kΩ at 1 kHz and illustrate the additionally gained surface due to the picosecond laser ablation on the front side electrodes. The safely injectable charge per pulse was found to be 635.75 μC/cm2 for such coated electrodes. Optical investigations show that this fabrication process offers an alternative to established lithographic processes for thin and flexible electrode arrays in neural implants.
        Open publication
      • Musso Mariacristina, Bamdadian Atieh, Denzer Simone, Umarova Roza, Hübner David, Tangermann Michael A novel BCI based rehabilitation approach for aphasia rehabilitation 2016 Proceedings of the 6th International Brain-Computer Interface Meeting: Past, Present, and Future, page(s): 104
      • Kuhner A, Schubert T, Cenciarini M, Maurer C, Burgard W A Probabilistic Approach Based on Random Forests to Estimating Similarity of Human Motion in the Context of Parkinson’s Disease 2016 Proc. of IEEE/RSJ International Conference on Intelligent Robots and Systems
        Show abstract The objective characterization of human motion is required in a variety of fields including competitive sports, rehabilitation and the detection of motor deficits. Nowadays, typically human experts evaluate the motor behavior. These evaluations are based on their individual experience which leads to a low inter- and intra-expert reliability. Standardized tests improve on the reliability but are still prone to subjective ratings and require human expert knowledge. This paper presents a novel method to characterize the motor state of Parkinson patients using full body motion capturing data based on a combination of multiple metrics. Our approach merges various metrics with a Random Forest and uses a probabilistic formulation to compute a one-dimensional measure for the performed motion. We present an application of our approach to the problem of relating subject motion to different classes like healthy subjects and Parkinson disease patients with deep brain stimulation switched on or off. In the experimental session we show that our measure leads to high classification rates and high entropy values for real-world data. Besides, we show that our method discriminates between Parkinson’s subjects (with and without stimulation) and healthy persons as good as the Unified Parkinson’s Disease Rating Scale (UPDRS).
      • Do C, Schubert T, Burgard W A Probabilistic Approach to Liquid Level Detection in Cups Using an RGB-D Camera 2016 Pro. Of the IEEE/RSJ Int. Conf. On Intelligent Robots and Systems (IROS) 2016
        Show abstract Robotic assistants have the potential to greatly improve our quality of life by supporting us in our daily activities. A service robot acting autonomously in an indoor environment is faced with very complex tasks. Consider the problem of pouring a liquid into a cup, the robot should first determine if the cup is empty or partially filled. RGB-D cameras provide noisy depth measurements which depend on the opaqueness and refraction index of the liquid. In this paper, we present a novel probabilistic approach for estimating the fill-level of a liquid in a cup using an RGB-D camera. Our approach does not make any assumptions about the properties of the liquid like its opaqueness or its refraction index. We develop a probabilistic model using features extracted from RGB and depth data. Our experiments demonstrate the robustness of our method and an improvement over the state of the art.
      • Marrett Karl, Wronkiewicz Mark, Tangermann Michael, Lee Adrian A User-Focused Study of Auditory P300 Brain-Computer Interface Design 2016 Proceedings of the 6th International Brain-Computer Interface Meeting: BCI Past, Present, and Future, page(s): 17
      • S. Stöcklin, A. Yousaf, L. Reindl Adaptive Elektronik zur effizienten drahtlosen Energieversorgung biomedizinischer Implantate 2016
      • Kuhl M, Manoli Y Area Reduction Techniques for Deep-Brain Probes with Electronic Depth Control 2016 invited paper, Proceedings of the IEEE International Symposium on Circuits and Systems (ISCAS), page(s): 1834 - 1837
      • Benedict Wright, Robert Mattmüller Automated Data Management Workflow Generation with Ontologies and Planning 2016
      • Tobias Schubert, Katharina Eggensperger, Alexis Gkogkidis, Frank Hutter, Tonio Ball, Wolfram Burgard Automatic Bone Parameter Estimation for Skeleton Tracking in Optical Motion Capture 2016 Proc of. IEEE International Conference on Robotics and Automation
        Show abstract Motion analysis is important in a broad range of contexts, including animation, bio-mechanics, robotics and experiments investigating animal behavior. For applications, in which tracking accuracy is one of the main require- ments, passive optical motion capture systems are widely used. Many skeleton tracking methods based on such systems use a predefined skeleton model, which is scaled once in the initialization step to the individual size of the character to be tracked. However, there are remarkable differences in the bone length relations across gender and even more across mammal races. In practice, the optimal skeleton model has to be determined in a manual and time-consuming process. In this paper, we reformulate this task as an optimization problem aiming to rescale a rough hierarchical skeleton structure to optimize probabilistic skeleton tracking performance. We solve this optimization problem by means of state-of-the-art black- box optimization methods based on sequential model-based Bayesian optimization (SMBO). We compare different SMBO methods on three real-world datasets with an animal and humans, demonstrating that we can automatically find skeleton structures for previously unseen mammals. The same methods also allow an automated choice of a suitable starting frame for initializing tracking.
      • Camilo Gordillo, Barbara Frank, Istvan Ulbert, Oliver Paul, Patrick Ruther, Wolfram Burgard Automatic Channel Selection in Neural Microprobes: A Combinatorial Multi-Armed Bandit Approach 2016 Proc. of the IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)
        Show abstract State-of-the-art neural microprobes contain hundreds of electrodes within a single shaft. Due to hardware and wiring restrictions, it is usually only possible to measure a small subset of the available electrodes simultaneously. The selection of the best channels is typically performed offline either manually or automatically. However, having a fixed selection for long-term observation does not allow the system to react to changes in the neural activity, and may therefore lead to the loss of important information. In this paper, we formulate the process of autonomously selecting the best subset of electrodes as a combinatorial multi-armed bandit problem with non-stationary rewards, thus allowing the probe to adapt its selection policies online. In order to minimize exploratory actions of the probe, we furthermore take advantage of the existing dependencies between neighboring channels. Our approach is an adaptation of the discounted upper confidence bounds (D-UCB) algorithm, and identifies the electrodes providing the largest amount of non-redundant information. To the best of our knowledge, this is the first online approach for the problem of electrode selection. In extensive experiments, we demonstrate that our solution is not only able to converge towards an average optimal selection policy, but it is also able to react to changes in the neural activity or to damages of the recording electrodes.
      • Umarova Roza, Castaño-Candamil Sebastián, Bamdadian Atieh, Kübel Sebastian, Musso Mariacristina, Kloeppel Stefan, Tangermann Michael BCI-Approach for Cognitive Rehabilitation in Stroke: Pilot Data from Patient with Spatial Neglect 2016 Proceedings of the 6th International Brain-Computer Interface Meeting: BCI Past, Present, and Future, page(s): 135
      • C. Bentler, S. Stöcklin, T. Stieglitz Blueprint for implantable Brain Computer Interfaces made of commercial off-the-shelf components 2016
      • Donkels C, Fariña Núñez MT, Janz P, Nestel S, Kirsch M, Huber S, Prinz M, Schulze-Bonhage A, Zentner J, Haas CA Characterization of Myelination Deficits in Dysplastic Human Temporal Neocortex. 2016 10th FENS Forum of Neuroscience; July 2-6, 2016; Copenhagen, Denmark
      • Castaño-Candamil Sebastián, Coenen Volker, Reinacher Peter, Piroth Tobias, Tangermann Michael EP 65. DBS-induced alpha desynchronization in the subthalamic nucleus of PD patients 2016 Clin Neurophysiol, volume: 127, issue: 9, page(s): e202 - e203
      • Castaño-Candamil Sebastián, Bamdadian Atieh, Kübel Sebastian, Umarova Roza, Tangermann Michael ERP Features Correlate with Reaction Time in a Covert-Attention Task 2016 Proceedings of the 6th International Brain-Computer Interface Meeting: BCI Past, Present, and Future, page(s): 179
      • Bamdadian Atieh, Denzer Simone, Musso Cristina, Tangermann Michael ERP Responses of the Elderly for Bisyllabic Word Stimuli 2016 Proceedings of the 6th International Brain-Computer Interface Meeting: BCI Past, Present, and Future, page(s): 180
      • Tulke S, Haas CA, Häussler U Expression of neuroprotective factors involved in cell survival in the CA2 region in mesial temporal lobe epilepsy. 2016
      • Meinel Andreas, Eggensperger Katharina, Tangermann Michael, Hutter Frank Hyperparameter Optimization for Machine Learning Problems in BCI 2016 Proceedings of the 6th International Brain-Computer Interface Meeting: BCI Past, Present, and Future, page(s): 184
      • O Cota, D Plachta, T Stieglitz, S Mohanan, Y Manoli, M Kuhl In vivo characterization of a versatile 8-channel digital biopotential recording system with sub µVRMS input noise 2016 Proc. International IEEE/EMBS Conference on Neural Engineering, page(s): 6311 - 6314
      • Göbel-Guéniot K, Kamberger R, Gerlach G, von Elverfeldt D, Haas CA, Korvink JG, Hennig J, LeVan P Insights into intrahippocampal networks using Magnetic Resonance Microscopy at 7 T. 2016
      • Eickenscheidt M, Stieglitz T Micro-folding Polyimide Structures for Neural Implants 2016 "Dreiländertagung" Swiss, Austrian 
and German Societies of Biomedical Engineering
      • Häussler U, Kilias A, Johnston M, Haas CA Mossy fiber sprouting in the hippocampal CA2 region in epilepsy. 2016
      • Häussler U, Johnston M, Kilias A, Janz P, Tulke S, Haas CA Mossy fiber synapses in the hippocampal CA2 region in temporal lobe epilepsy. 2016
      • Meyer Johannes, Meinel Andreas, Schreiner Thomas, Rasch Björn, Tangermann Michael P26 Versuchspersonenunabhängige Single-Trial-Erkennung von langsamen Wellen im Schlaf-EEG 2016 Somnologie, volume: 20, issue: 1, page(s): 75 - 76
      • Meinel Andreas, Schlichtmann Eva, Koller Torsten, Reis Janine, Tangermann Michael Predicting Single-Trial Motor Performance from Oscillatory EEG in Chronic Stroke Patients 2016 Proceedings of the 6th International Brain-Computer Interface Meeting: BCI Past, Present, and Future, page(s): 140
      • Orcinha C, Münzner G, Gerlach J, Follo M, Haas CA Recombinant central reelin fragment prevents epilepsy-induced motility of adult dentate granule cells. 2016
      • Janz P, Hauser P, Heining K, Nestel S, Kretz O, Kirsch M, Egert U, Haas CA Region-specific activity changes during epileptogenesis determine subcellular Arc mRNA localization and synaptic plasticity of dentate granule cells. 2016
      • Castaño-Candamil Sebastián, Dähne Sven, Tangermann Michael Relevant Frequency Estimation in EEG Recordings for Source Power Co-Modulation 2016 Proceedings of the 6th International Brain-Computer Interface Meeting: BCI Past, Present, and Future, page(s): 156
      • Kilias A, Häussler U, Heining K, Kumar A, Froriep UP, Haas CA, Egert U Theta rhythm impaired in the epileptic hippocampal formation. 2016
    • 2015

      • Pothof F, Galchev T, Patel M, Sayed Herbawi A, Paul O, Ruther P 128-channel deep brain recording probe with heterogenously integrated analog CMOS readout for focal epilepsy localization 2015
      • Kuhl M, Manoli Y A 0.01 mm² Fully-Differential 2-Stage Amplifier with Reference-Free CMFB Using an Architecture-Switching-Scheme for Bandwidth Variation 2015 Proceedings of the European Solid-State Circuits Conference (ESSCIRC), page(s): 287 - 290
      • Mottaghi S, Pinnel R, Hofmann UG A 16-bit high-voltage digital charge-control electrical stimulator. 2015 IFMBE
      • Schwaderlapp NL, Janz P, Leupold J, Häussler U, Lange T, Elverfeldt D, Haas C, Hennig J, Harsan LA, LeVan P A longitudinal study of MR correlates during epileptogenesis in a mouse model of temporal lobe epilepsy. 2015
      • S. Stöcklin, A. Yousaf, T. Volk, L. Reindl A Maximum Efficiency Point Tracking System for Wireless Powering of Biomedical Implants 2015
      • Almajidy R, Boudria Y, Hofmann UG, Besio W, Mankodiya K A Multimodal 2D Brain Computer Interface. 2015 Conf Proc IEEE Eng Med Biol Soc
        Show abstract n this work we used multimodal, non-invasive brain signal recording systems, namely Near Infrared Spectroscopy (NIRS), disc electrode electroencephalography (EEG) and tripolar concentric ring electrodes (TCRE) electroencephalography (tEEG). 7 healthy subjects participated in our experiments to control a 2-D Brain Computer Interface (BCI). Four motor imagery task were performed, imagery motion of the left hand, the right hand, both hands and both feet. The signal slope (SS) of the change in oxygenated hemoglobin concentration measured by NIRS was used for feature extraction while the power spectrum density (PSD) of both EEG and tEEG in the frequency band 8-30Hz was used for feature extraction. Linear Discriminant Analysis (LDA) was used to classify different combinations of the aforementioned features. The highest classification accuracy (85.2%) was achieved by using features from all the three brain signals recording modules. The improvement in classification accuracy was highly significant (p= 0.0033) when using the multimodal signals features as compared to pure EEG features.
      • S. Stöcklin, T. Volk, A. Yousaf, L. Reindl A Programmable and Self-Adjusting Class E Amplifier for Efficient Wireless Powering of Biomedical Implants 2015
      • Heizmann S, Kilias A, Okujeni S, Boehler C, Ruther P, Egert U, Asplund M Accurate neuronal tracing of microelectrodes based on PEDOT-dye coatings 2015
      • Heizmann Stefanie, Kilias Antje, Okujeni Samora, Boehler Christian, Ruther Patrick, Egert Ulrich, Asplund Maria Accurate neuronal tracing of microelectrodes based on PEDOT-dye coatings 2015 2015 7th International IEEE/EMBS Conference on Neural Engineering (NER), page(s): 386 - 389
      • Häussler U, Sulger J, Rinas K, Kilias A, Haas CA Altered connectivity of the hippocampal CA2 region in temporal lobe epilepsy. 2015
      • Schröer S, Killmann I, Frank B, Völker M, Fiederer LD, Ball T, Burgard W An Autonomous Robotic Assistant for Drinking. 2015 Proceedings of 2015 IEEE International Conference on Robotics and Automation 2015
      • Ayub S, Schwärzle M, Paul O, Ruther P An intracerebral probe with integrated 10x1 µLED array for optogenetic experiments at 460 nm 2015
      • Szczurkowska J, Pischedda F, Pinto B, Manago F, Haas CA, Papaleo F, Schäfer M, Piccoli G, Cancedda L Autism-associated proteins Negr1 and FGFR2 together regulate cell migration and autism-related behaviors in mice. 2015
      • Tobias Schubert, Alexis Gkogkidis, Tonio Ball, Wolfram Burgard Automatic Initialization for Skeleton Tracking in Optical Motion Capture 2015 Proc of. IEEE International Conference on Robotics and Automation
        Show abstract The ability to track skeletal movements is impor- tant in a variety of applications including animation, biological studies and animal experiments. To detect even small move- ments, such a method should provide highly accurate estimates. Besides that it should not impede the mammal in its motion. This motivates the usage of a passive optical motion capture system. Thereby the main challenges are the initialization, the association of the unlabeled markers to their corresponding segment also across the frames, and the estimation of the skeleton configuration. While many existing approaches can deal with the latter two problems, they typically need a specific pose for initialization. This is rather unpractical in the context of animal tracking and often requires a manual initialization process. In this paper, we present an approach to reliably track animals and humans in marker-based optical motion capture systems with freely attached markers. Our method is also able to perform an automatic initialization without any pre- or post-processing of the data. To achieve this, our approach utilizes a large database of previously observed poses. We present our algorithm and its evaluation on real-world data sets with an animal and humans. The results demonstrate that our initialization method performs accurately for the most kind of initial poses and our tracking approach outperforms a popular fully automatic skeleton tracking method especially with respect to the smoothness of the motion.
      • Schubert T, Gkogkidis A, Ball T, Burgard W Automatic Initialization for Skeleton Tracking in Optical Motion Capture. 2015 Proceedings of 2015 IEEE International Conference on Robotics and Automation
      • Kumar, S S, Wülfing, J, Winterer, L, Okujeni, Samora, Boedecker, J, Wimmer, R, Riedmiller R, Becker B, Egert U Autonomous control of network activity 2015 Bernstein Conference 2015, page(s): T24
      • Wallrabe U Axicons et al. – highly apsherical adaptive optical elements for the life sciences 2015 , volume: 2015, page(s): 251 - 256
        Show abstract This paper summarizes the recent research on tunable aspherical micro optics in regard to applications in the life sciences. Particular emphasis is placed on adaptive lenses and a very special class among them, conical lenses, so-called axicons. While various mechanisms to tune the asphericity are reviewed, the focus of the discussion is placed on piezo¬electric actuation because of its speed and thermal actuation because of its design freedom. The major appli¬cations in life sciences are microscopy, cell handling, and neurosciences. Possible further applications are referred to as well.
      • A. Mirzaei, A. Kumar, D.K. Leventhal, N. Mallet, J.D. Berke, R. Schmidt Basal ganglia dynamics during movement Initiation: a computational model for transient beta oscillations. 2015 2015 11. Göttingen Jahrestagung 2015 der Neurowissenschaftlichen Gesellschaft (NWG)
      • Martinez-Lizana E, Aiple F, Blumberg J, Coenen V, Reinacher P, Stieglitz T, Rickert J, Gierthmühlen M, Dümpelmann M, Ball T, Schulze-Bonhage A Clinical evaluation of micro-electrode recordings in human patients (Micro-Rec). 2015
      • Sayed Herbawi A, Mildenberger B, Larramendy F, Holzhammer T, Galchev T, Paul O, Ruther P CMOS-based high-density neural probes with improved scheme for addressing recording and stimulation channels 2015
      • Sayed Herbawi A, Larramendy F, Galchev T, Holzhammer T, Mildenberger B, Paul O, Ruther P CMOS-based neural probe with enhanced electronic depth control 2015
      • Tangermann Michael, Reis Janine, Meinel Andreas Commonalities of Motor Performance Metrics are Revealed by Predictive Oscillatory EEG Components 2015 Proceedings of the 3rd International Congress on Neurotechnology, Electronics and Informatics (NEUROTECHNIX), page(s): 32 - 38
      • Aldinger Johannes, Mattmüller Robert, Göbelbecker Moritz Complexity Issues of Interval Relaxed Numeric Planning 2015
      • Engesser Thorsten, Bolander Thomas, Mattmüller Robert, Nebel Bernhard Cooperative Epistemic Multi-Agent Planning With Implicit Coordination 2015
      • Mottaghi S, Hofmann UG Dynamically Adjusted Scalable Electrical Stimulator for Exciteable Tissue 2015 IEEE Express
      • Meinel Andreas, Castaño-Candamil Juan Sebastián, Dähne Sven, Reis Janine, Tangermann Michael EEG Band Power Predicts Single-Trial Reaction Time in a Hand Motor Task 2015 Neural Engineering (NER), 2015 7th International IEEE/EMBS Conference on, page(s): 182 - 185
      • Feurer Matthias, Klein Aaron, Eggensperger Katharina, Springenberg Jost, Blum Manuel, Hutter Frank Efficient and Robust Automated Machine Learning 2015
      • S. Stöcklin, T. Volk, A. Yousaf, J. Albesa, L.M.Reindl Efficient Inductive Powering of Brain Implanted Sensors 2015
      • Leicht J, Amayreh M, Moranz C, Maurath D, Hehn T, Manoli Y Electromagnetic Vibration Energy Harvester Interface IC with Conduction-Angle-Controlled Maximum-Power-Point Tracking and Harvesting Efficiencies of up to 90% 2015 Proceedings of the IEEE International Solid-State Circuits Conference (ISSCC), page(s): 368 - 369
      • Watter Manuel, Springenberg Jost, Boedecker Joschka, Riedmiller Martin Embed to Control: A Locally Linear Latent Dynamics Model for Control from Raw Images 2015 , page(s): 2728 - 2736
      • Janz P, Häussler U, Kilias A, Kretz O, Kirsch M, Egert U, Haas CA Entorhinal Input Contributes to an Aberrant Hippocampal Circuitry in Mesial Temporal Lobe Epilepsy. 2015
      • Fiedler, E, Porto Cruz, M. F, Cota Monjarás, O. F, Stieglitz, T Evaluation of Thin-film Temperature Sensors for Integration in Neural Probes 2015
      • Hassler C, Ehler N, Singh V, Xie Y, Martini N, Kirch RD, Prucker O, Rühe JR, Hofmann UG, Stieglitz T Fabrication and Implantation of Hydrogel Coated, Flexible Polyimide Electrodes. 2015 IEEE Express
      • Schwärzle M, Pothof F, Paul O, Ruther P High-resolution neural depth probe with integrated 460 nm light emitting diode for optogenetic applications 2015
      • Schwärzle M, Pothof F, Paul O, Ruther P High-resolution optrode with integrated light source for deeper brain regions 2015
      • Ashouri Vasari, D.,, Ordonez, J.S., Furlanetti, L.,, Döbrössy, M, Coenen, V.,, Stieglitz,T. Hybrid Multimodal Deep Brain Probe (DBS array) for Advanced Brain Re-search 2015 , page(s): 410 - 413
      • Cota C, Plachta D, Stieglitz T, Manoli Y, Kuhl M In-vivo Characterization of a 0.8 – 3 µVRMS Input-noise Versatile CMOS Pre-amplifier 2015 Proceedings of the International IEEE/EMBS Conference on Neural Engineering, page(s): 458 - 461
      • T. Volk, S. Stöcklin, C. Bentler, J. Ordonez, S. Hussain, A. Yousaf, T. Stieglitz, L.M. Reindl Inductive micro-tunnel for an efficient power transfer 2015
      • Göbel K, Gerlach J, Kamberger R, von Elverfeldt D, Haas CA, Korvink JG, Hennig J, LeVan P Investigation of structural alterations in epileptogenesis using MR microscopy. 2015
      • C. Boehler, F. Oberueber, T. Stieglitz, M. Asplund, , M. Asplund Iridium Oxide (IrOx) serves as adhesion promoter for conducting polymers on neural microelectrodes 2015 Neural Engineering (NER), 2015 7th International IEEE/EMBS Conference on, page(s): 410 - 413
        Show abstract Conducting polymers (CPs) as functional coatings on microelectrodes enable the realization of neural probes with superior electrical properties compared to metallized probes. Besides significantly lower impedance and enhanced charge delivery capacity, CPs further feature the possibility to release drugs from their bulk which can be done exclusively from these materials. Thus the usage of CPs at the neural interface for recording or stimulation of neural tissue is of great interest. A drawback that has however been observed at usage of conducting polymers in vitro and in vivo is the weak adhesion of the polymer to the substrate which ultimately leads to delamination of the coatings. This effect has limited the applicability of polymer coatings on neural probes despite their overall promising potential. In our study we address this gap by introducing Iridium Oxide (IrOx) as adhesion promoter for long-term stabilization of CP films. Exaggerated stressing protocols revealed superior adhesion of the polymer to the rough structure of IrOx and electrochemical measurements indicated unrestricted polymer functionality. With the herein proposed strategy a major obstacle of using conducting polymers at the neural interface could be efficiently targeted and thus applicability of CPs for neural interfaces can be extended in future electrode generations.
      • Burget Felix, Maurer Christoph, Burgard Wolfram, Bennewitz Maren Learning Motor Control Parameters for Motion Strategy Analysis of Parkinson’s Disease Patients 2015 IEEE/RSJ International Conference on Intelligent Robots and Systems, volume: 1, issue: 1, page(s): 5019 - 5025
        Show abstract Although the neurological impairments of Parkinson’s disease (PD) patients are well known to go along with motor control deficits, e.g., tremor, rigidity, and reduced movement, not much is known about the motor control parameters affected by the disease. In this paper, we therefore present a novel approach to human motions analysis using motor control strategies with joint weight parameterization. We record the motions of healthy subjects and PD patients performing a hand coordination task with the whole-body XSens MVN motion capture system. For our motion strategy analysis we then follow a two step approach. First, we perform a complexity reduction by mapping the recorded human motions to a simplified kinematic model of the upper body. Second, we reproduce the recorded motions using a Jacobian weighted damped least squares controller with adaptive joint weights. We developed a method to iteratively learn the joint weights of the controller with the mapped human joint trajectories as reference input. Finally, we use the learned joint weights for a quantitative comparison between the motion control strategies of healthy subjects and PD patients. Other than expected from clinical experience, we found that the joint weights are almost evenly distributed along the arm in the PD group. In contrast to that, the proximal joint weights of the healthy subjects are notably larger than the distal ones.
        Open publication
      • A.Dosovitskiy, J.T.Springenberg, T.Brox Learning to Generate Chairs with Convolutional Neural Networks 2015 IEEE International Conference on Computer Vision and Pattern Recognition (CVPR)
      • Schwärzle M et al. LED-based neural probes for optogenetics 2015
      • Kamberger R, Göbel K, Gerlach J, Gruschke OG, LeVan P, Leupold J, von Elverfeldt D, Hennig J, Haas CA, Korvink JG Magnetresonanz-kompatibler Mini-Inkubator für die Untersuchung der Epileptogenese in vitro. / Magnetic resonance compatible Mini-incubator for the examination of Epileptogenesis in vitro. 2015 , page(s): 445 - 447
      • Kamberger R, Göbel K, Gerlach J, Gruschke OG, LeVan P, Leupold J, von Elverfeldt D, Hennig J, Haas CA, Korvink JG Merging Brain Slice Culturing And Magnetic Resonance Microscopy. 2015
      • Feurer M., Klein A., Eggensperger K., Springenberg J., Blum M., Hutter F. Methods for Improving Bayesian Optimization for AutoML 2015 ICML 2015 AutoML Workshop, volume: to appear Open publication
      • Göbel K, Gerlach J, Kamberger R, Leupold J, von Elverfeldt D, Haas C, Korvink JG, Hennig J, LeVan P Micro-MR correlates of cellular-level alterations in epileptogenesis. 2015
      • Kamberger R, Göbel K, Gerlach J, Gruschke OG, LeVan P, Leupold J, von Elverfeldt D, Hennig J, Haas CA, Korvink JG MR-COMPATIBLE MINI-INCUBATOR FOR IN VITRO STUDIES OF EPILEPTOGENESIS IN ORGANOTYPIC HIPPOCAMPAL SLICE CULTURES. 2015
      • Eitel, A., Springenberg, J. T., Spinello, L., Riedmiller, M., Burgard, W. Multimodal Deep Learning for Robust RGB-D Object Recognition 2015 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)
      • Capogrosso, M, Bonizzato, M, Petrini, F, Raspopovioc, S, Stieglitz, T, Rossini, P.M, Micera, S Multisensory feedback enables fine force control in a bidirectional prosthetic hand 2015
      • Gerlach J, Donkels C, Münzner G, Haas CA Neurogenesis in organotypic hippocampal slice cultures is strongly affected by glial cell activation and inflammatory processes. 2015
      • T. Volk, C. Bentler, A. Yousaf, S. Stöcklin, T. Stieglitz, L. M. Reindl Novel concept for a wireless and batteryless brain implant array 2015
      • Almajidy R, Le KS, Hofmann UG Novel near infrared sensors for hybrid BCI applications 2015 SPIE
      • Winkler Irene, Debener Stefan, Müller Klaus-Robert, Tangermann Michael On the Influence of High-Pass Filtering on ICA-Based Artifact Reduction in EEG-ERP 2015 Proc. 37th Int. Conf. of the IEEE Eng. in Medicine and Biology Soc. (EMBC), page(s): 4101 - 4105
      • Bär Sebastien, Weigel Matthias, von Elverfeld Dominik, Hennig Jürgen, Leupold Jochen Optimizing the bSSFP flip angle for imaging hyperpolarized samples 2015
      • Kim, Christopher, Kilias, Antje, Sahasranamam, Ajith, Rotter, Stefan, Egert, Ulrich, Kumar, Arvind Origin and control of dynamic instability in a computational model of epileptic network 2015 Bernstein Conference 2015
      • Castaño-Candamil Sebastián, Meinel Andreas, Reis Janine, Tangermann Michael P186. Correlates to influence user performance in a hand motor rehabilitation task 2015 Clin Neurophysiol, volume: 126, issue: 8, page(s): e166 - e167 Open publication
      • Castaño-Candamil Juan, Meinel Andreas, Dähne Sven, Tangermann Michael Probing Meaningfulness of Oscillatory EEG Components with Bootstrapping, Label Noise and Reduced Training Sets 2015 Proc. 37th Int. Conf. of the IEEE Eng. in Medicine and Biology Soc. (EMBC), page(s): 5159 - 5162
      • Domhan T., Springenberg J., Hutter F. Speeding up Automatic Hyperparameter Optimization of Deep Neural Networks by Extrapolation of Learning Curves 2015 Proceedings of the 24th International Joint Conference on Artificial Intelligence (IJCAI), volume: to appear Open publication
      • Burget Felix, Bennewitz Maren Stance Selection for Humanoid Grasping Tasks by Inverse Reachability Maps 2015 IEEE International Conference on Robotics and Automation, volume: 1, issue: 1, page(s): 5669 - 5674
        Show abstract In grasping tasks carried out with humanoids, knowledge about the robot’s reachable workspace is important. Without this knowledge, it might be necessary to repeatedly adapt the stance location and call an inverse kinematics solver before a valid robot configuration to reach a given grasping pose can be found. In this paper, we present an approach to select an optimal stance location in SE(2) for a humanoid robot’s feet relative to a desired grasp pose. We use a precomputed representation of the robot’s reachable workspace that stores quality information in addition to spatial data. By inverting this representation we obtain a so-called inverse reachability map (IRM) containing a collection of potential stance poses for the robot. The generated IRM can subsequently be used to select a statically stable, collision-free stance configuration to reach a given grasping target. We evaluated our approach with a Nao humanoid in simulation and in experiments with the real robot. As the experiments show, using our approach optimal stance poses can easily be obtained. Furthermore, the IRM leads to a substantially increased success rate of reaching grasping poses compared to other meaningful foot placements within the vicinity of the desired grasp.
        Open publication
      • Springenberg, J. T., Dosovitskiy, A., Brox, T., Riedmiller, M. Striving for Simplicity: The All Convolutional Net 2015 arXiv:1412.6806, also appeared at ICLR 2015 Workshop Track
      • Janz, Philipp, Savanthrapadian, Shakuntala, Häussler, Ute, Kilias, Antje, Nestel, Sigrun, Kretz, Oliver, Kirsch, Matthias, Bartos, Marlene, Egert, Ulrich, Haas, Carola A Structural and functional plasticity of entorhinal input contributes to an epileptic hippocampal circuitry 2015 Society for Neuroscience Abstracts
      • Janz P, Savanthrapadian S, Häussler U, Kilias A, Nestel S, Kretz O, Kirsch M, Bartos M, Egert U, Haas CA Structural and functional plasticity of entorhinal input contributes to an epileptic hippocampal circuitry. 2015
      • Donkels C, Pfeifer D, Huber S, Nakagawa J, van Velthoven V, Weyerbrock A, Zentner J, Haas CA The expression of myelin-associated genes is reduced in mild focal cortical dysplasia. 2015
      • Häussler U, Rinas K, Huber S, Haas CA The hippocampal CA2 region in temporal lobe epilepsy. 2015
      • Somerlik-Fuchs KH, Hofmann UG, Stieglitz T, Schulze-Bonhage A The Influence of Stimulation Parameters on the Relative Phase Clustering Index. 2015 IEEE Express
      • Killias A, Häussler U, Heining K, Froriep UP, Kumar A, Haas CA, Egert U Theta oscillation impaired along the septo-temporal axis of the epileptic hippocampal formation. 2015
      • Kilias A, Häussler U, Kumar A, Froriep UP, Haas CA, Egert U Theta oscillations and neuronal firing along the septotemporal axis of the epileptic hippocampal formation. 2015
      • Bamdadian Atieh, Guan Cuntai, Ang Kai, Xu Jianxin Towards Improvement of MI-BCI Performance of Subjects with BCI Deficiency 2015 Proc. Int. IEEE Conf. on Neural Eng. (NER), page(s): 17 - 20
      • Karsten Scheibler, Leonore Winterer, Ralf Wimmer, Bernd Becker Towards Verification of Artificial Neural Networks 2015 GI/ITG/GMM Workshop “Methoden und Beschreibungssprachen zur Modellierung und Verifikation von Schaltungen und Systemen”
        Show abstract We consider the safety verification of controllers obtained via machine learning. This is an important problem as the employed machine learning techniques work well in practice, but cannot guarantee safety of the produced controller, which is typically represented as an artificial neural network. Nevertheless, such methods are used in safety-critical environments. In this paper we take a typical control problem, namely the Cart Pole System (a.k.a. inverted pendulum), and a model of its physical environment and study safety verification of this system. To do so, we use bounded model checking (BMC). The created formulas are solved with the SMT-solver iSAT3. We examine the problems that occur during solving these formulas and show that extending the solver by special deduction routines can reduce both memory consumption and computation time on such instances significantly. This constitutes a first step towards verification of machine-learned controllers, but a lot of challenges remain.
      • Wapler MC, Weirich C, Stürmer M, Wallrabe U ULTRA-COMPACT, LARGE-APERTURE SOLID STATE ADAPTIVE LENS WITH ASPHERICAL CORRECTION 2015 18th International Conference on Solid-State Sensors, Actuators and Microsystems (Transducers 2015), volume: 2015
      • T. Volk, A. Yousaf, J. Albesa, S. Stöcklin, L. M. Reindl Wireless Power Distribution System for Brain Implants 2015
      • Volk T, Yousaf A, Albesa J, Stoecklin S, Hussain S, Gkogkidis A, Ball T, Reindl L Wireless Power Distribution System for Brain Implants. 2015
    • 2014

      • Muller N, Manoli Y, Kuhl M A 1.6nS, 16µW, 30V Gm-C Integrator for Offset Voltage Monitoring in Neural Stimulators 2014 Proceedings of the IEEE International Symposium on Circuits and Systems (ISCAS), page(s): 2381 - 2384
      • Lampe T, Fiederer LD, Voelker M, Knorr A, Riedmiller M, Ball T A Brain-Computer Interface for High-Level Remote Control of an Autonomous, Reinforcement-Learning-Based Robotic System for Reaching and Grasping. 2014 IUI '14 Proceedings of the 19th international conference on Intelligent User Interfaces, volume: IUI 2014, page(s): 83 - 88
        Show abstract We present an Internet-based brain-computer interface (BCI) for controlling an intelligent robotic device with autonomous reinforcement-learning. BCI control was achieved through dry-electrode electroencephalography (EEG) obtained during imaginary movements. Rather than using low-level direct motor control, we employed a high-level control scheme of the robot, acquired via reinforcement learning, to keep the users cognitive load low while allowing control a reachinggrasping task with multiple degrees of freedom. High-level commands were obtained by classification of EEG responses using an artificial neural network approach utilizing timefrequency features and conveyed through an intuitive user interface. The novel combination of a rapidly operational dry electrode setup, autonomous control and Internet connectivity made it possible to conveniently interface subjects in an EEG laboratory with remote robotic devices in a closed-loop setup with online visual feedback of the robots actions to the subject. The same approach is also suitable to provide homebound patients with the possibility to control state-of-the-art robotic devices currently confined to a research environment. Thereby, our BCI approach could help severely paralyzed patients by facilitating patient-centered research of new means of communication, mobility and independence.
        Open publication
      • Lampe, Thomas, Fiederer, Lukas D. J., Voelker, Martin, Knorr, Alexander, Riedmiller, Martin, Ball, Tonio A Brain-Computer Interface for High-Level Remote Control of an Autonomous, Reinforcement-Learning-Based Robotic System for Reaching and Grasping 2014 International Conference on Intelligent User Interfaces (IUI 2014)
      • Wapler MC, Stürmer M, Wallrabe U A Compact, Large-Aperture Tunable Lens with Adaptive Spherical Correction 2014 2014 International Symposium on Optomechatronic Technologies (ISOT)
      • A. Mirzaei, A. Kumar, D.K. Leventhal, N. Mallet, J.D. Berke, R. Schmidt A computational model of basal ganglia dynamics during movement initiation: striatal indirect pathway drives transient beta oscillations 2014 10th Bernstein Conference Göttingen
      • Egert U, Kilias A, Heinig K, Froriep U, Kumar A, Häussler U, Kumar A, Haas CA A fingerprint of epilepsy during ongoing activity. 2014 Freiburg-Imperial Symposium
      • Sherif M, Manoli Y A Novel Fully Integrated Low-Power CMOS BPSK Demodulator for Medical Implantable Receivers 2014 Proceedings of the IEEE International Symposium on Circuits and Systems (ISCAS), page(s): 1098 - 1101
      • Kohler F, Kiele P, Ordonez JS, Stieglitz T, Schuettler M A polymer-metal two-step concept for hermetic neural implant packages 2014 , volume: 36, page(s): 113 - 116
      • Hertle Andreas, Dornhege Christian, Keller Thomas, Mattmüller Robert, Ortlieb Manuela, Nebel Bernhard An Experimental Comparison of Classical, FOND and Probabilistic Planning 2014 Springer, page(s): 297 - 308
      • Lampe Thomas, Riedmiller Martin Approximate Model-Assisted Neural Fitted Q-Iteration 2014 IEEE International Joint Conference on Neural Networks (IJCNN 2014)
      • Bödecker J, Springenberg J, Wülfing J, Riedmiller M Approximate Real-Time Optimal Control Based on Sparse Gaussian Process Models 2014 Adaptive Dynamic Programming and Reinforcement Learning (ADPRL-2014)
      • Neef M, Donkels C, Häussler U, Bechstein M, Kirsch M, Haas CA Astrocytes pre-activated by ciliary neurotrophic factor show neuroprotective properties in a mouse model of mesial temporal lobe epilepsy. 2014 11th European Congress on Epileptology - Stockholm
        Show abstract Purpose: Activation of astrocytes is a hallmark of hippocampal sclerosis in patients with mesial temporal lobe epilepsy. However, the specific role of activated astrocytes in the epileptic brain is discussed controversially. We have previously shown that activation of astrocytes by a single, defined stimulus enhances their neuroprotective properties. We injected ciliary neurotrophic factor (CNTF) prior to an epilepsy-inducing injection of kainate (KA) and found that epilepsy-related brain damage was ameliorated and epileptiform activity reduced. In the present study we investigated the underlying molecular mechanisms. Method: Adult C57Bl/6 mice received either a single CNTF injection into the dorsal hippocampus or sequential injections of CNTF and KA (CNTF+KA) followed by real-time qPCR analysis or immunohistochemistry for glial glutamate transporters (GLT1/GLAST), glutamine synthetase (GS), inwardly-rectifying K+ channel (Kir 4.1) or connexin 43 and 30 (Cx43/Cx30) to characterize molecular changes of preactivated astrocytes. Results: We show that intrahippocampal injection of CNTF induces a rapid and sustained activation of astrocytes reflected by up-regulation of glial fibrillary acidic protein (GFAP). Moreover, CNTF signaling via phosphorylation and nuclear translocation of STAT3 as part of the JAK/STAT pathway was specifically activated in GFAP-positive astrocytes. Real-time RT-PCR analysis revealed that CNTF-mediated pre-activation of astrocytes followed by KA injection resulted in a significant up-regulation of Cx43 and Cx30 mRNAs indicating enhanced coupling properties of astrocytes via gap junctions. Moreover GLT1/GLAST and GS mRNA expression was significantly enhanced pointing to improved glutamate clearance from the synaptic cleft. Furthermore, Kir4.1 mRNA was significantly higher expressed in CNTF+KA-injected animals. Complementary immunocytochemistry reveaIed that up-regulation of all these mRNAs occurred exclusively in astrocytes. Conclusion: In summary, our results indicate that activation of astrocytes prior to an excitotoxic injury leads to molecular changes indicative of the observed neuroprotective and anti-epileptic action.
      • Vysotska O, Frank B, Ulbert I, Paul O, Ruther P, Stachniss C, Burgard W Automatic Channel Selection and Neural Signal Estimation across Channels of Neural Probes 2014 Proc. of the IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)
      • Sreedhar Saseendran Kumar, Jan Wülfing, Joschka Boedecker, Ralf Wimmer, Martin Riedmiller, Bernd Becker, Ulrich Egert Autonomous Control of Network Activity 2014 9th International Meeting on Substrate-Integrated Microelectrode Arrays (MEA)
        Show abstract Electrical stimulation of the brain is used to treat neurological disorders. Yet it is unknown how to find stimulation patterns that produce desired results with the least interference. Towards this goal, we tested a generic closed-loop paradigm that autonomously optimizes stimulation settings. We used neuronal networks coupled to a reinforcement learning based controller to maximize response lengths.
      • Schaefer M, Loreth D, Pöttker B, Schwald K, Kretz O, Radyushkin K, Haas CA, Heimrich B CHARACTERIZATION OF ENTORHINAL-HIPPOCAMPAL CONNECTIVITY, BEHAVIOR, AND SEIZURE SUSCEPTIBILITY IN NEGR1-DEFICIENT MICE 2014
        Show abstract The perforant path provides the major excitatory hippocampal input from the entorhinal cortex and degenerative alterations are associated with cognitive dysfunctions including Alzheimer`s disease. However, the molecular mechanisms for guidance and target specificity are unclear. We examined in this context the immunoglobulin superfamily cell adhesion molecule Neuronal Growth Regulator 1 (NEGR1) in mice. In situ hybridization demonstrated Negr1 expression both in entorhinal cortex projection neurons and in targeted hippocampal granule cells. NEGR1 overexpression in NSC-34 cells stimulated neurite growth and attracted axons of co-cultured primary neurons suggesting that homophilic interaction of NEGR1 promotes neuronal connectivity. Organotypic slice co-cultures of entorhinal cortices from actin-EGFP mice and NEGR1-deficient hippocampi indicated that NEGR1 is required for axon growth and guidance of entorhinal axons to granule cells. DiI tracing of the perforant path in NEGR1-deficient mice revealed fasciculation and growth abnormalities including aberrant projections of entorhinal axons into the hilar region. Following single injection of the GABA-A receptor antagonist pentylenetetrazole NEGR1-deficient mice exhibited increased seizure susceptibility. Subtle abnormalities were observed in behavioral tasks. These results involve NEGR1 in the development of entorhinal-hippocampal connectivity. Malformations of the perforant path may contribute to increased seizure susceptibility and behavioral abnormalities in NEGR1-deficient mice.
      • Sherif M, Manoli Y Design and Implementation of an RF CMOS Differential LNA for 403MHz Applications 2014 Proceedings of the IEEE International Symposium on Circuits and Systems (ISCAS), page(s): 1400 - 1403
      • Sherif M, Al-Saegh S, Manoli Y Design of 1mW CMOS OOK Super-Regenerative Receiver for 402-405MHz Medical Applications 2014 Proceedings of the IEEE International Symposium on Circuits and Systems (ISCAS), page(s): 690 - 693
      • Häussler U, Marx M, Janz P, Haas CA Differential vulnerability of interneurons along the septotemporal axis of the hippocampus in experimental epilepsy. 2014 11th European Congress on Epileptology - Stockholm
        Show abstract Purpose: Loss of interneurons is considered as a reason for hyperexcitability of the hippocampus in temporal lobe epilepsy (TLE). Here we used a focal mouse model for TLE to characterize the vulnerability of interneurons along the septotemporal axis of the hippocampus and to record epileptic activity in corresponding areas. Method: Adult C57Bl/6 mice received a unilateral injection of kainate into the septal hippocampus which induced recurrent epileptic seizures, hippocampal sclerosis and granule cell dispersion (GCD). We implanted four electrodes along the septotemporal axis of the hippocampus to measure local field potentials. In situ hybridization for glutamate decarboxylase 67 (GAD67) mRNA and immunolabeling for parvalbumin, neuropeptide Y (NPY) and GAD65 was used to characterize changed inhibition in the whole hippocampus. Results: We show that epileptiform activity is not strongest at the injection site with most prominent cell death and GCD but in the intermediate hippocampus which seems histologically less affected. Quantification of GAD67 mRNA-positive cells revealed a significant loss of inhibitory interneurons close to the injection site and a reduction in the intermediate hippocampus. Yet, different interneurons populations showed differential vulnerability: Parvalbumin-positive cells were lost on a substantially larger extent than NPY-positive interneurons. Remarkably, granule cells showed a compensatory reaction to epileptiform activity characterized by an upregulation of GAD67 mRNA in cell bodies, GAD65 protein in mossy fiber synapses and NPY in mossy fibers. Conclusion: Together with our previous study on neurogenesis (Häussler et al., Cerebral Cortex 2013, 22(1):26-36) these data indicate that the intermediate hippocampus comprises a network with higher epileptogenicity than the dorsal, sclerotic hippocampus. This might be due to a shifted excitation-inhibition balance originating from the reduction in inhibitory interneurons and the addition of newborn, hyperexcitable granule cells. Acknowledgements: Supported as part of the Excellence Cluster ‘BrainLinks-BrainTools’ by the German Research Foundation, grant EXC1086; Scientific Society Freiburg.
      • Alexey Dosovitskiy, Jost Tobias Springenberg, Martin Riedmiller, Thomas Brox Discriminative Unsupervised Feature Learning with Convolutional Neural Networks 2014 28th Annual Conference on Neural Information Processing Systems (NIPS)
      • Almajidy R, Kirch R, Christ O, Hofmann UG Estimating the spatial resolution of fNIRS sensors for BCI purposes 2014 SPIE Digital Library, page(s): 1 - 9 Open publication
      • Stieglitz, T, Ordonez, J.S, Hassler, C, Fiedler, E, Kohler, F, Boretius, T, Boehler, C, Asplund, M, Schuettler, M Flexible Polymer-based Neuroprosthetic Interfaces in Fundamental and Translational Research 2014
      • Karsten Scheibler, Bernd Becker Implication Graph Compression inside the SMT Solver iSAT3 2014 GI/ITG/GMM Workshop “Methoden und Beschreibungssprachen zur Modellierung und Verifikation von Schaltungen und Systemen”
        Show abstract The iSAT algorithm aims at solving boolean combinations of linear and non-linear arithmetic constraint formulas (including transcendental functions), and thus is suitable to verify safety properties of systems consisting of both, linear and non-linear behaviour. The iSAT algorithm tightly integrates interval constraint propagation into the conflict-driven clause-learning framework. During the solving process, this may result in a huge implication graph. This paper presents a method to compress the implication graph on-the-fly. Experiments demonstrate that this method is able to reduce the overall memory footprint up to an order of magnitude.
      • Xie Y, Hassler C, Stieglitz T, Seifert A, Hofmann UG In-situ monitoring of brain tissue reaction of chronically implanted electrodes with an optical coherence tomography fiber system 2014 Proc. of SPIE, volume: 8947, issue: 27, page(s): 1 - 7 Open publication
      • Niederbühl A, Pernice V, Rotter S Inferring causation from correlation in sparse networks 2014 Open publication
      • Abdo N, Spinello L, Burgard W, Stachniss C Inferring What to Imitate in Manipulation Actions by Using a Recommender System 2014 Proc. of the IEEE International Conference on Robotics & Automation (ICRA)
      • Paul O, Ruther P MEMS and more for the brain - THE cluster of excellence BrainLinks-BrainTools at the University of Freiburg 2014 , page(s): 1 - 4
      • Schwärzle M, Elmlinger P, Paul O, Ruther P Miniaturized Tool for Optogenetics Based on an LED and an Optical Fiber Interfaced by a Silicon Housing 2014 , page(s): 5252 - 5255
      • A. Hornung, S. Boettcher, C. Dornhege, A. Hertle, J. Schlagenhauf, M. Bennewitz Mobile Manipulation in Cluttered Environments with Humanoids: Integrated Perception, Task Planning, and Action Execution 2014 Proceedings of the IEEE-RAS International Conference on Humanoid Robots (Humanoids)
      • Barz F, , Paul O, Ruther P Modular assembly concept for 3D neural probe prototypes offering high freedeom of design and alignement precision 2014 , page(s): 3977 - 3980
      • Göbel K, Leupold J, Dhital B, LeVan P, Reisert M, Gerlach J, Kamberger R, Haas CA, Hennig J, von Elverfeldt D, Korvink JG MR Microscopy and DTI of Organotypic Hippocampal Slice Cultures. 2014
      • Szczurkowska J, Pischedda F, Manago F, Haas C, Papaleo F, Schäfer M, Piccoli G, Cancedda L NEGR1 IS REQUIRED FOR TRANSITION OF MIGRATING PYRAMIDAL NEURONS FROM LAYER V TO LAYER II/III OF THE MOUSE CEREBRAL CORTEX 2014
        Show abstract The mammalian cerebral cortex is a remarkably complex structure, and establishment of cortical neural circuitries requires its unique laminar organization. During perinatal development, newborn pyramidal neurons migrate along radial glia fibers, to create the six-layered structure of the neocortex. Disruption in neural migration can lead to brain malformations with functional consequences on proper wiring of the neuronal network, as already described in neurodevelopmental disorders such as Autism Spectrum Disorders (ASD). Common knowledge indicates cell-adhesion molecules (CAMs) as essential for proper neural migration. Neuronal growth regulator 1 (Negr1) is a CAM, and NEGR1 gene mutations have been recently associated to ASD. By in utero electroporation coupled with RNA interference (siRNA), we downregulated Negr1 levels in late-born pyramidal neurons migrating to the superficial layers of the neocortex. We found that Negr1 siRNA caused ectopic positioning of neurons concentrated at the border between layer 5 and layer 4 of the somatosensory cortex. Downregulation of Negr1 did not cause migration defects in the motor or prefrontal cortices. We found that FGFR2 (also associated to autism) and its partner NCAM physically and functionally interact with Negr1. Here, we proved that downregulation of NCAM in utero resulted in a strikingly similar phenotype on neuronal migration as found for Negr1. Interestingly, downregulation of Negr1 in the embryonic somatosensory cortex resulted in decreased number of ultrasound vocalizations in pups. These data suggest that Negr1/FGFR2/NCAM complex is necessary for proper neuronal migration of pyramidal neurons in the somatosensory cortex, indicating a possible role for this complex in autism.
      • Micera S, Raspopovic S, Capogrosso M, Carpaeto J, Ganata G, Oddo C.M, Cipriani C, Stieglitz T, Schuettler M, Navarro X, Raffo L, Barbaro M, Rossini P M Neurocontrolled bidirectional artificial upper limb and hand prosthesis (NEBIAS) 2014
      • Holc, K., Jakob, A., Weig, T., Köhler, K., Schwarz, U.T., Müller, A., Pauls, M., Wapler, M., Wallrabe, U., Ambacher, O. New tools for optogenectics: Nitride laser diodes combined with axicons for non-invasive neuronal stimulation" 2014
      • Kuderer M, Sprunk C, Kretzschmar H, Burgard W Online Generation of Homotopically Distinct Navigation Paths 2014 Proc. of the IEEE International Conference on Robotics and Automation (ICRA)
      • Meyer J, Kuderer M, Müller J, Burgard W Online Marker Labeling for Fully Automatic Skeleton Tracking in Optical Motion Caputure 2014 Proc. of the IEEE International Conference on Robotics and Automation (ICRA)
      • Tangermann Michael, Müller Katja, Nolte Aleke, Schumacher Julia, Zhutovsky Paul, Blankertz Benjamin P374: Detecting spatial auditory attention in cocktail-party situations 2014 Clin Neurophysiol, volume: 125, page(s): S147
      • Höhne Johannes, Tangermann Michael P827: Beyond P300: an auditory ERP paradigm with sequential stimulation 2014 Clin Neurophysiol, volume: 125, page(s): S263
      • Kilias A, Froriep UP, Häussler U, Kumar A, Haas CA, Egert U Phase coupling of neuronal firing to hippocampal network rhythms is preserved under epileptic conditions. 2014 11th European Congress on Epileptology - Stockholm
        Show abstract Purpose: In mesio-temporal lobe epilepsy (MTLE) the hippocampal network is pathologically restructured resulting in the emergence of epileptiform activity (EA). EA occurs transiently and alternates with putatively “normal” activity patterns. In healthy animals, hippocampal activity is dominated by network oscillations that couple information transfer between hippocampal subregions and shape the firing probability of single neurons. Previously we showed phase-shifted coupling of the theta-rhythm between the medial entorhinal cortex (MEC) and the sclerotic dentate gyrus (DG) in epileptic mice. Whether phase-shifted oscillations are accompanied by shifted neuronal firing across hippocampal fields or locally with respect to ongoing network oscillations is investigated here. Both conditions would severely alter information processing in the epileptic hippocampal formation. Method: We recorded local field potential rhythms and multi-unit activity in freely behaving epileptic animals using the intrahippocampal kainate mouse model of MTLE. We chronically implanted multi-site silicon electrode arrays sampling the whole entorhinal-hippocampal (EC-HC) loop. Results: We show that neurons in all investigated substructures of the EC-HC loop fired phase-coupled to theta and gamma oscillations. Coupling to theta rhythm was comparable in strength and phase-angle across healthy and epileptic groups. Furthermore, coupling properties of neurons recorded in the weakly-sclerotic DG, a region showing highest epileptogenicity, were comparable to those in the non-sclerotic DG. While the phase-coupling of neurons persisted in epileptic mice, the average firing rate of cells from the DG and parahippocampal region was increased. Conclusion: Hippocampal neuronal firing is modulated with the local theta-rhythm. Thus, a phase-shift between the theta-rhythms of the MEC and DG implies a mismatch of neuronal firing across these structures that could tune the hippocampal network towards seizure susceptibility via pathological plasticity. Support: BMBF (FKZ 01GQ0420, 01GQ0830), DFG within the Cluster of Excellence BrainLinks-BrainTools (EXC1086), EC (EFRE - TIGER)
      • Nakagawa J, Donkels C, Fauser S, Beckervordersandforth J, Prinz M, Zentner J, Haas CA Poster: Characterization of dyslamination and of alterations in layer-specific neuron-composition in focal cortical dysplasia. 2014 11th European Congress on Epileptology - Stockholm
        Show abstract Objective: Focal cortical dysplasia (FCD), a cortical malformation arising during prenatal development, is a major cause of pharmaco-resistant focal epilepsy thus frequently becoming object to neurosurgical resection. However, little is known about the histopathologic and molecular phenotypes underlying the cortical dyslamination patterns in human FCD. The structural, molecular and cellular characterization of an impaired cortical composition and a possible coherence between neuron-specific alterations and epileptogenicity of FCD are subject of the current study. Methods: Layer-specific protein expression (Reelin, Calbindin, Calretinin, SMI32, Parvalbumin, TLE4) was studied by immunohistological techniques on paraffin-embedded sections including double immunolabeling in neuropathologically confirmed mild FCD Type 1 and 2a (n=15), FCD2b (n=29) and was compared to a control group with (n=6) or without epilepsy (n=3 post mortem cases). Neuron-specific protein levels were analyzed by quantitative Western blot analysis. Following systematic quantification of neocortical neuronal density and neuron-specific protein levels statistical analysis of layer-specific neuronal subpopulations was performed according to age at surgery and brain region. Results: Even in severe dyslamination of FCD2b with impaired laminar assignment particularly of layer 3 and 5 pyramidal cells we found a rudimentary preservation of laminar structure using lamina-specific markers. The quantitative analysis of layer-specific neuronal subpopulations revealed a highly significant, age-related decrease in distinct interneuron subpopulations especially of Parvalbumin-positive interneurons primarily located in layer 4 whereas supragranular interneurons expressing Calbindin and Calretinin were only marginally affected. Furthermore, TLE4-positive projection neurons in layer 6 were increased in numbers. Conclusion: Our findings suggest that cortical dyslamination is associated with disturbances in cell proliferation or differentiation, but not primarily with a general migration defect. A differential vulnerability of especially deep-layered interneurons and an increase of distinct layer-specific neurons, respectively, results in a profound, age-related alteration of the neocortical neuronal composition in FCD.
      • Haas CA, Münzner G, Tinnes S, Follo M Poster: EPILEPSY-INDUCED MOTILITY OF ADULT DENTATE GRANULE CELLS IS CAUSED BY INACTIVATION OF THE REELIN SIGNALING PATHWAY. 2014 9th FENS Forum of Neuroscience - Milan
      • Donkels C, Pfeifer D, Huber S, van Velthoven V, Weyerbrock A, Zentner J, Haas CA Poster: Gene Expression Profiling of Focal Cortical Dysplasia Shows Reduced Expression of Myelin-Associated Genes in Dysplastic Temporal Lobe. 2014 11th European Congress on Epileptology - Stockholm
        Show abstract Purpose: Focal cortical dysplasias (FCD) are local malformations of the human neocortex, originating during pre- and perinatal brain development. They are frequent causes of medically intractable focal epilepsy, associated with a high seizure frequency. To date little is known about the pathomechanisms leading to the architectural and functional abnormalities associated with FCD. Mostly, morphological studies have been carried out to analyze the pathology of the disease. In this study, a whole transcriptome screening was performed to understand the molecular mechanisms leading to this cortical malformation. Method: Human Gene 1.0 ST arrays (Affymetrix) were used for microarray analysis on dysplastic and non-dysplastic temporal lobe tissue, obtained from children (n=7; mean age 2; range 1-5 years) and adult patients (n= 7; mean age 19; range 6-36 years) who had undergone surgical treatment due to intractable epilepsy or low grade tumor resection (n=8; mean age 17; range 1-27 years). Microarray data were validated by real-time PCR, in situ hybridization and immunohistochemistry for genes of interest. Results: The whole transcriptome screening of dysplastic compared to non-dysplastic temporal neocortex revealed that approximately 0.1% of genes are differentially expressed, with the majority being down-regulated in FCD. In particular, genes affecting oligodendrocyte differentiation and myelination were found to be down-regulated in dysplastic temporal lobes of children and adults. These data could be confirmed by real-time PCR. Accordingly, myelin basic protein-expressing cells were drastically reduced in dysplastic cortex. Conclusion: Our transcriptome screening revealed that only a relatively low number of genes (0.1%) are differentially expressed in the dysplastic temporal neocortex when analyzed in the chronic stage of the disease. Nevertheless, we found a significantly reduced expression of myelin-associated genes indicating a disturbance of oligodendrocyte differentiation and myelin sheet formation/maintenance in FCD. Supported by the Deutsche Forschungsgemeinschaft (DFG FA 775/2-1)
      • Gerlach J, Donkels C, Münzner G, Haas CA Poster: Strong activation of glial cells causes progressive extinction of neurogenesis in organotypic hippocampal slice cultures. 2014 9th FENS Forum of Neuroscience - Milan
        Show abstract In the subgranular zone (SGZ) of the dentate gyrus new neurons are generated throughout life by a sophisticated sequence of proliferation, differentiation and migration. To investigate possible factors affecting SGZ neurogenesis under pathological conditions, we used organotypic hippocampal slice cultures (OHSC) as they are a commonly used in vitro system and, interestingly, gradually lose their neurogenic capacity. Since OHSC share key features with CNS pathologies (e.g. strong glial activation), we hypothesized that the degree of glial activation could limit the extent of neurogenesis. To address this question, we analyzed the expression of factors regulating neurogenesis or glial cell activation in OHSC by RT-qPCR. We found that most neurogenic genes were down-regulated, whereas factors released by activated glial cells were strongly induced. To monitor neurogenic dynamics in OHSC we used transgenic mice, in which EGFP is exclusively expressed in immature neurons under the pro-opiomelanocortin (POMC) promotor. Measuring EGFP signal intensity revealed a rapid decrease within the first week of culturing. To identify the glial influence, we enhanced glial reactivity by the treatment with ciliary neurotrophic factor or diminished it by applying a P2Y12 receptor antagonist or indomethacin. The degree of glial activation determined the neurogenic outcome. Therefore, our results highlight the important role of a balanced activation of glial cells for hippocampal neurogenesis. This could be of particular medical interest, as most CNS diseases are accompanied by glial activation, which could impede the regenerative potential of neurogenesis. Supported by the DFG within the Cluster of Excellence “BrainLinks-BrainTools” (DFG grant EXC1086).
      • Janz P, Häussler U, Kilias A, Egert U, Haas CA Poster: Structural Plasticity of the Entorhinal Input on Dentate Granule Cells in Mesial Temporal Lobe Epilepsy. 2014 9th FENS Forum of Neuroscience - Milan
        Show abstract Dentate granule cells receive their major excitatory input from the entorhinal cortex (EC) via the perforant path. Although pathological reorganization associated with mesial temporal lobe epilepsy (i.e. neuronal cell loss, granule cell dispersion, mossy fiber sprouting) has been studied extensively, it remains uncertain whether the entorhinal input is altered under epileptic conditions. To address this question adult C57Bl/6 or transgenic Thy1-EGFP mice received a unilateral, intrahippocampal kainate or saline injection, followed by stereotaxic infusion of biotinylated dextran amine (BDA), an anterograde neuronal tracer, into the medial EC 14 days later. After a survival period of 21 days, brain sections were immunohistochemically stained for BDA and vGLUT-1, labeling the traced fibers and their presynaptic terminals. First, we mapped the projection from the medial EC to the outer molecular layer of the hippocampus, namely the medial perforant path (MPP), confirming the topographic results of previous tracing studies. Interestingly, following kainate treatment, the width of the projection remained unchanged, although dentate granule cells dispersed broadly. In turn, the density of traced fibers was reduced and high-power confocal imaging revealed axonal varicosities within the MPP. Yet to be quantified, a preliminary assessment of synaptic densities pointed to a decline of MPP terminals, projecting onto postsynaptic dendrites, while postsynaptic spines may be upregulated. In conclusion, our findings suggest that under epileptic conditions the MPP is preserved on a macroscopic scale, but it appears altered on the level of individual synapses. Supported by the DFG within the Cluster of Excellence “BrainLinks-BrainTools” (DFG grant EXC1086).
      • Heizmann S, Kilias A, Ringwald P, Okujeni S, Böhler C, Ruther P, Egert U, Asplund M Precise detection of recording positions by accurate neural tracing from PEDOT-based microelectrodes 2014
      • Koenemann J, Burget F, Bennewitz M Real-time Imitation of Human Whole-Body Motions by Humanoids 2014 Proc. of the IEEE International Conference on Robotics & Automation (ICRA)
      • Koenemann Jonas, Burget Felix, Bennewitz Maren Real-time Imitation of Human Whole-Body Motions by Humanoids 2014 IEEE International Conference on Robotics and Automation, volume: 1, issue: 1, page(s): 2806 - 2812
        Show abstract In this paper, we present a system that enables humanoid robots to imitate complex whole-body motions of humans in real time. In our approach, we use a compact human model and consider the positions of the endeffectors as well as the center of mass as the most important aspects to imitate. Our system actively balances the center of mass over the support polygon to avoid falls of the robot, which would occur when using direct imitation. For every point in time, our approach generates a statically stable pose. Hereby, we do not constrain the configurations to be in double support. Instead, we allow for changes of the support mode according to the motions to imitate. To achieve safe imitation, we use retargeting of the robot’s feet if necessary and find statically stable configurations by inverse kinematics. We present experiments using human data captured with an Xsens MVN motion capture system. The results show that a Nao humanoid is able to reliably imitate complex whole-body motions in real time, which also include extended periods of time in single support mode, in which the robot has to balance on one foot.
        Open publication
      • Becker-Asano C., Arras K. O., Nebel B. Robotic tele-presence with DARYL in the wild 2014 Proc. of the 2nd Intl. Conf. on Human-Agent Interaction, page(s): 91 - 95
      • Dang W, Barz F, Paul O, Ruther P Technology for the highly compact interconnection of neural probes with flexible ribbon cables 2014
      • R. Schmidt, N. Mallet, D.K. Leventhal, F. Chen, J.D. Berke The globus pallidus cancels actions by suppressing striatal output 2014 Program No. 442.17. Neuroscience 2014 Abstracts. Washington: Society for Neuroscience, 2014. Online.
      • T. Volk, J. Albesa, S. Stöcklin, A. Yousaf, L. M. Reindl Theoretical Approach to Setup a Multi-Antenna System for Brain Implants 2014
        Show abstract Due to the progressive development, there is a significant demand of passively powered implants in biomedical research. Small dimensions make it possible to place the devices into inaccessible or critical positions. As consequence, the coupling factor between reader and implant antenna is slight. This work therefore provides a novel analysis of inductive coupled systems based on numerical methods for determining a proper coil configuration. Keywords: inductive coupling, wireless power transfer, three antenna systems, deep brain stimulation.
      • Tangermann Michael, Schnorr Norah, Musso Mariacristina Towards Aphasia Rehabilitation with BCI 2014 Proceedings of the 6th International Brain-Computer Interface Conference 2014, page(s): 369 - 372
      • Karsten Scheibler, Bernd Becker Using Interval Constraint Propagation for Pseudo-Boolean Constraint Solving 2014 Formal Methods in Computer-Aided Design
        Show abstract This work is motivated by (1) a practical application which automatically generates test patterns for integrated circuits and (2) the observation that off-the-shelf state-of-the-art pseudo-Boolean solvers have difficulties in solving instances with huge pseudo-Boolean constraints as created by our application. Derived from the SMT solver iSAT3 we present the solver iSAT3p that on the one hand allows the efficient handling of huge pseudo-Boolean constraints with several thousand summands and large integer coefficients. On the other hand, experimental results demonstrate that at the same time iSAT3p is competitive or even superior to other solvers on standard pseudo-Boolean benchmark families.
      • Maier D, Zohouri R, Bennewitz M Using Visual and Auditory Feedback for Instrument-Playing Humanoids 2014 Proceedings of the IEEE-RAS International Conference on Humanoid Robots (Humanoids)
      • Gremmelspacher T, Häussler U, Gerlach J, Haas CA VOLUNTARY WHEEL-RUNNING SEQUENTIALLY STIMULATES PROGENITOR DIFFERENTIATION AND PROLIFERATION DURING EARLY STAGES OF NEUROGENESIS IN THE ADULT DENTATE GYRUS. 2014
        Show abstract Many studies on neurogenesis have shown that in the adult dentate gyrus (DG) progenitor cells proliferate and give rise to young neurons integrating into the neuronal network. The DG neurogenic niche can be modulated by external stimuli, e.g. physical activity which is the best described physiological stimulus for neurogenesis in adult mice. So far, mice have been exposed to wheel-running for >14 days to activate neurogenesis. Here, we used shorter running periods to describe the timeline of running-induced neurogenesis and to characterize early changes in the DG. Adult C57Bl/6N mice had free access to running wheels for two or seven days. Subsequently, we performed immunocytochemistry for glial fibrillary acidic protein (GFAP) and Nestin to label stem cells, doublecortin (DCX) for young neurons and Ki-67 for proliferating cells. To detect changes in the molecular characteristics of the neurogenic niche, we performed real-time RT-qPCR for neurotrophic factors (BDNF, BMP4). We show that short running periods are sufficient to activate neurogenesis, as indicated by a continuous increase in DCX labeling. In contrast, GFAP- and Nestin-positive cells were reduced after two days, demonstrating that stem cell proliferation and differentiation do not arise simultaneously. Instead, we hypothesize that proliferation succeeds progenitor differentiation after a period of exhaustion of the stem cell pool, as confirmed by Ki-67 staining. Real-time RT-qPCR analysis revealed a modulated expression of niche factors BDNF and BMP4 already after 2 days privileging differentiation. In summary, our data point to a two-phasic mechanism involved in early running-induced neurogenesis. Support: MOTI-VATE program, Medical Faculty Freiburg.
    • 2013

      • Wang,X, Gkogkidis, A, Gierthmuehlen, M, Freimann, T.M, Henle, C, Raab, M, Fischer, J, Fehrenbacher, T, Kohler, F, Foerster, K, Haberstrooh, J, Schulze-Bonhage, A, Aertsen, A, Stieglitz, T, Schuettler, M, Rickert, J, Ball, T. Acute and chronic µECoG-based brain mapping using a wireless implant system in a large animal model 2013
      • Schuettler, M, Kohler, F, Fischer, J, Fehrenbacher, T, Gkogkidis,A, Mohrlok, R, Paetzold, J, Boven, K.-H, Moeller, A, Henle, C, Meier, W, Raab, M, Ordonez, J.S, Wang, X, Gierthmuehlen, M, Ball, T, Foerster, K, Haberstroh, J, Freiman, T.M, Stieglitz, T, Ri An Implant for Closed-Loop ECoG Recording and Stimulation 2013
      • Rickert, J, Kohler, F, Fischer, J, Fehrenbacher, T, Gkogkidis, A, Mohrlock, R, Paetzold, J, Boven, K.-H, Henle, C, Meier, W, Raab, M, Ordonez, J.S, Wang, X, Gierthmuehlen, M, Ball, T, Foerster, K, Haberstroh, J, Freimann, T.M, Stieglitz, T, Schuettler, M An implantable brain-computer interface for chronic cortical recording and sti-mulation using a micro-ECoG electrode array 2013
      • Roth R, Rostek R, Cobry K, Woias P Doppelresist-Prozess zur Herstellung eines Mikro-Thermogenerators im cross-plane Design mit reflowgelöteten Kontakten - Two-layer process for a micro thermoelectric cross-plane generator with reflow soldered contacts 2013 Proceedings Mikrosystemtechnik Kongress
      • Nebel Bernhard, Dornhege Christian, Hertle Andreas How Much Does a Household Robot Need To Know In Order To Tidy Up Your Home? 2013 AAAI Press
      • Stieglitz, T, Rubehn, B, Boretius, T, Henle, C, Ordonez, J, Meier, W, Hassler, C, Boehler, C, Kohler, F, Schuettler, M Interfacing with the Nervous System 2013
      • Dornhege Christian, Hertle Andreas, Nebel Bernhard Lazy Evaluation and Subsumption Caching for Search-Based Integrated Task and Motion Planning 2013
      • Kilias A, Froriep UP, Häussler U, Kumar A, Haas CA, Egert U Local interplay between hippocampal single cell firing and network oscillations is preserved under epileptic conditions 2013
      • Fiedler E, Ordonez J, Stieglitz T Modular Assembly of Flexible Thin-Film Electrod Arrays Enabled by a Laser-Structured Ceramic Adapter 2013
      • Göbel K, Kamberger R, Gerlach J, Gruschke OG, Leupold J, LeVan P, von Elverfeldt D, Korvink JG, Haas CA, Hennig J MR Microscopy of Organotypic Hippocampal Slice Cultures: A First Look at the Anatomy. 2013
      • Göbel K, Kamberger R, Gerlach J, Gruschkeb, Leupold J, LeVan P, von Elverfeldt D, Korvink JG, Haas CA, Hennig J MR Microscopy of Organotypic Hippocampal Slice Cultures: First Steps to an In Vitro Approach for Experimental Epilepsy Research 2013
      • Gierthmuehlen, M, Wang, X, Kuehn, C, Gkogkidis, A, Henle, C, Raab, M, Fischer, J, Kohler, F, Haberstroh, J, Stieglitz, T, Schuettler M, Rickert, J, Ball, T, Freimann, T.M Neurosurgical approach to the cerebral cortex for acute and chronic cortical sti-mulation and recording studies in minipigs and sheep 2013
      • Nakagawa J, Fauser S, Donkels C, Beckervordersandforth J, Prinz M, Zentner J, Haas CA Poster: Balloon cells in the epileptogenic human cortex of focal cortical dysplasia type 2b 2013
      • Donkels C, Fauser S, Pfeifer D, Huber S, Zentner J, Haas CA Poster: Gene expression profiling and morphological analysis of mild focal cortical dysplasias (FCD) 2013
      • Häussler U, Haas CA Poster: Temporal lobe epilepsy is associated with an irreversible change in the neurogenic niche 2013
      • Haas CA, Tinnes S, Ringwald J Poster: Tissue Inhibitor of Matrix Metalloproteases-1 Impairs Reelin Processing in Experimental Epilepsy 2013
      • Christ O, Somerlik-Fuchs KH, Stieglitz T, Schulze-Bonhage A, Hofmann UG Prescreening Seizure-like Events in a Rat Model of Epilepsy: A 2D Video Processing Method 2013
      • Kohler F, Ulloa Suarez M, Ordonez J, Stieglitz T, Schüttler M Reliability Investigations and Improvements of Interconnection Technologies for the Wireless Brain-Machine Interface - 'BrainCon' 2013 6th IEEE-EMBS Conference on Neural Engineering, page(s): 1013 - 1016
      • Ordonez J, Boehler C, Schuettler M, Stieglitz T Silicone Rubber and Thin-Film Polyimide for Hybrid Neural Interfaces - A MEMS-based Adhesion Promotion Technique 2013 Proc IEEE-EMBS Neural Eng Conf, page(s): 872 - 875
      • Häussler U, Gremmelspacher T, Hubbe A, Haas CA The neurogenic niche is irreversibly changed in experimental epilepsy 2013
      • Roth R, Rostek R, Lenk G, Kratschmer M, Cobry K, Woias P TWO-LAYER PROCESS FOR A MICRO THERMOELECTRIC CROSS-PLANE GENERATOR WITH ELECTROPLATING AND REFLOW SOLDERING 2013 Transducers & Eurosensors XXVII, page(s): 486 - 489
      • Burget F, Hornung A, Bennewitz M Whole-Body Motion Planning for Manipulation of Articulated Objects 2013 Proc. of the IEEE International Conference on Robotics & Automation (ICRA)
    • 2012

      • Löhr Johannes, Eyerich Patrick, Keller Thomas, Nebel Bernhard A Planning Based Framework for Controlling Hybrid Systems 2012
      • Hertle Andreas, Dornhege Christian, Keller Thomas, Nebel Bernhard Planning with Semantic Attachments: An Object-Oriented View 2012
      • Becker-Asano C., Arras K.O., Nebel B., Ishiguro H. The Effect of Anthropomorphism on Social Tele-Embodiment 2012 IROS 2012 Workshop on Human-Agent Interaction
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  • Other publications 6

    • 2016

    • 2015

      • Stieglitz T Neuroimplantate 2015 Spektrum der Wissenschaft-Spezial, Physik-Mathematik-Technik, page(s): 6 - 13
      • Stieglitz, T, Schuettler, M, Plachta, D.T.T Neuroprothetik heute und morgen 2015 Orthopaedie Technik, issue: 6/15, page(s): 32 - 37
    • 2014

      • Kumar S S, Wülfing J, Boedecker J, Wimmer R, Riedmiller R, Becker B, Egert U Autonomous control of network activity 2014 Proc of the 9th Int’l Meeting on Substrate-Integrated Microelectrode Arrays (MEA)
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