Max Planck Institute for Biological Cybernetics

Tubingen, Germany

Max Planck Institute for Biological Cybernetics

Tubingen, Germany

The Max Planck Institute for Biological Cybernetics is located in Tübingen, Baden-Württemberg, Germany. It is one of 80 institutes in the Max Planck Society .The institute is studying signal and information processing in the brain. We know that our brain is constantly processing a vast amount of sensory and intrinsic information by which our behavior is coordinated accordingly. How the brain actually achieves these tasks is less well understood, for example, how it perceives, recognizes, and learns new objects. The scientists at the Max Planck Institute for Biological Cybernetics aim to determine which signals and processes are responsible for creating a coherent percept of our environment and for eliciting the appropriate behavior. Scientists of three departments and seven research groups are working towards answering fundamental questions about processing in the brain, using different approaches and methods. Wikipedia.

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Kerr J.N.D.,Max Planck Institute for Biological Cybernetics | Nimmerjahn A.,Salk Institute for Biological Studies
Current Opinion in Neurobiology | Year: 2012

Uncovering the relationships between animal behavior and cellular activity in the brain has been one of the key aims of neuroscience research for decades, and still remains so. Electrophysiological approaches have enabled sparse sampling from electrically excitable cells in freely moving animals that has led to the identification of important phenomena such as place, grid and head-direction cells. Optical imaging in combination with newly developed labeling approaches now allows minimally invasive and comprehensive sampling from dense networks of electrically and chemically excitable cells such as neurons and glia during self-determined behavior. To achieve this two main imaging avenues have been followed: Optical recordings in head-restrained, mobile animals and miniature microscope-bearing freely moving animals. Here we review progress made toward functional cellular imaging in freely moving rodents, focusing on developments over the past few years. We discuss related challenges and biological applications. © 2011 Elsevier Ltd.

Goense J.,Max Planck Institute for Biological Cybernetics | Merkle H.,U.S. National Institutes of Health | Logothetis N.,Max Planck Institute for Biological Cybernetics | Logothetis N.,University of Manchester
Neuron | Year: 2012

The six cortical layers have distinct anatomical and physiological properties, like different energy use and different feedforward and feedback connectivity. It is not known if and how layer-specific neural processes are reflected in the fMRI signal. To address this question we used high-resolution fMRI to measure BOLD, CBV, and CBF responses to stimuli that elicit positive and negative BOLD signals in macaque primary visual cortex. We found that regions with positive BOLD responses had parallel increases in CBV and CBF, whereas areas with negative BOLD responses showed a decrease in CBF but an increase in CBV. For positive BOLD responses, CBF and CBV increased in the center of the cortex, but for negative BOLD responses, CBF decreased superficially while CBV increased in the center. Our findings suggest different mechanisms for neurovascular coupling for BOLD increases and decreases, as well as laminar differences in neurovascular coupling.

Buzsaki G.,New York University | Logothetis N.,Max Planck Institute for Biological Cybernetics | Logothetis N.,University of Manchester | Singer W.,Max Planck Institute for Brain Research
Neuron | Year: 2013

Despite the several-thousand-fold increase of brain volume during the course of mammalian evolution, the hierarchy of brain oscillations remains remarkably preserved, allowing for multiple-time-scale communication within and across neuronal networks at approximately the same speed, irrespective of brain size. Deployment of large-diameter axons of long-range neurons could be a key factor in the preserved time management in growing brains. We discuss the consequences of such preserved network constellation in mental disease, drug discovery, and interventional therapies.

Werner S.,Max Planck Institute for Biological Cybernetics | Noppeney U.,Max Planck Institute for Biological Cybernetics
Cerebral Cortex | Year: 2011

Multisensory events in our natural environment unfold at multiple temporal scales over extended periods of time. This functional magnetic resonance imaging study investigated whether the brain uses transient (onset, offset) or sustained temporal codes to effectively integrate incoming visual and auditory signals within the cortical hierarchy. Subjects were presented with 1) velocity-modulated radial motion, 2) amplitude-modulated sound, or 3) an in phase combination of both in blocks of variable durations to dissociate transient and sustained blood oxygen level-dependent responses. Audiovisual interactions emerged primarily for transient onset and offset responses highlighting the importance of rapid stimulus transitions for multisensory integration. Strikingly, audiovisual interactions for onset and offset transients were dissociable at the functional and anatomical level. Low-level sensory areas integrated audiovisual inputs at stimulus onset in a superadditive fashion to enhance stimulus salience. In contrast, higher order association areas showed subadditive integration profiles at stimulus offset possibly reflecting the formation of higher order representations. In conclusion, multisensory integration emerges at multiple levels of the cortical hierarchy using different temporal codes and integration profiles. From a methodological perspective, these results highlight the limitations of conventional event related or block designs that cannot characterize these rich dynamics of audiovisual integration. © 2011 The Author. Published by Oxford University Press. All rights reserved.

Lee H.,Max Planck Institute for Biological Cybernetics | Noppeney U.,Max Planck Institute for Biological Cybernetics
Journal of Neuroscience | Year: 2011

Face-to-face communication challenges the human brain to integrate information from auditory and visual senses with linguistic representations. Yet the role of bottom-up physical (spectrotemporal structure) input and top-down linguistic constraints in shaping the neural mechanisms specialized for integrating audiovisual speech signals are currently unknown. Participants were presented with speech and sinewave speech analogs in visual, auditory, and audiovisual modalities. Before the fMRI study, they were trained to perceive physically identical sinewave speech analogs as speech (SWS-S) or nonspeech (SWS-N). Comparing audiovisual integration (interactions) of speech, SWS-S, and SWS-N revealed a posterior-anterior processing gradient within the left superior temporal sulcus/gyrus (STS/STG): Bilateral posterior STS/STG integrated audiovisual inputs regardless of spectrotemporal structure or speech percept; in left mid-STS, the integration profile was primarily determined by the spectrotemporal structure of the signals; more anterior STS regions discarded spectrotemporal structure and integrated audiovisual signals constrained by stimulus intelligibility and the availability of linguistic representations. In addition to this "ventral" processing stream, a "dorsal" circuitry encompassing posterior STS/STG and left inferior frontal gyrus differentially integrated audiovisual speech andSWSsignals. Indeed, dynamic causal modeling and Bayesian model comparison provided strong evidence for a parallel processing structure encompassing a ventral and a dorsal stream with speech intelligibility training enhancing the connectivity between posterior and anterior STS/STG. In conclusion, audiovisual speech comprehension emerges in an interactive process with the integration of auditory and visual signals being progressively constrained by stimulus intelligibility along the STS and spectrotemporal structure in a dorsal fronto-temporal circuitry. ©2011 the authors.

Werner S.,Max Planck Institute for Biological Cybernetics | Noppeney U.,Max Planck Institute for Biological Cybernetics
Cerebral Cortex | Year: 2010

Merging information from multiple senses provides a more reliable percept of our environment. Yet, little is known about where and how various sensory features are combined within the cortical hierarchy. Combining functional magnetic resonance imaging and psychophysics, we investigated the neural mechanisms underlying integration of audiovisual object features. Subjects categorized or passively perceived audiovisual object stimuli with the informativeness (i.e., degradation) of the auditory and visual modalities being manipulated factorially. Controlling for low-level integration processes, we show higher level audiovisual integration selectively in the superior temporal sulci (STS) bilaterally. The multisensory interactions were primarily subadditive and even suppressive for intact stimuli but turned into additive effects for degraded stimuli. Consistent with the inverse effectiveness principle, auditory and visual informativeness determine the profile of audiovisual integration in STS similarly to the influence of physical stimulus intensity in the superior colliculus. Importantly, when holding stimulus degradation constant, subjects' audiovisual behavioral benefit predicts their multisensory integration profile in STS: only subjects that benefit from multisensory integration exhibit superadditive interactions, while those that do not benefit show suppressive interactions. In conclusion, superadditive and subadditive integration profiles in STS are functionally relevant and related to behavioral indices of multisensory integration with superadditive interactions mediating successful audiovisual object categorization. The Author © 2009. Published by Oxford University Press. All rights reserved.

Wallace D.J.,Max Planck Institute for Biological Cybernetics | Kerr J.N.D.,Max Planck Institute for Biological Cybernetics
Current Opinion in Neurobiology | Year: 2010

Although we know enormous amounts of detailed information about the neurons that make up the cortex, placing this information back into the context of the behaving animal is a serious challenge. The functional cell assembly hypothesis first described by Hebb (The Organization of Behavior; a Neuropsychological Theory. New York: Wiley; 1949) aimed to provide a mechanistic explanation of how groups of neurons, acting together, form a percept. The vast number of neurons potentially involved make testing this hypothesis exceedingly difficult as neither the number nor locations of assembly members are known. Although increasing the number of neurons from which simultaneous recordings are made is of benefit, providing evidence for or against a hypothesis like Hebb's requires more than this. In this review, we aim to outline some recent technical advances, which may light the way in the chase for the functional cell assembly. © 2010 Elsevier Ltd.

Mooij J.M.,Max Planck Institute for Biological Cybernetics
Journal of Machine Learning Research | Year: 2010

This paper describes the software package libDAI, a free & open source C++ library that provides implementations of various exact and approximate inference methods for graphical models with discrete-valued variables. libDAI supports directed graphical models (Bayesian networks) as well as undirected ones (Markov random fields and factor graphs). It offers various approximations of the partition sum, marginal probability distributions and maximum probability states. Parameter learning is also supported. A feature comparison with other open source software packages for approximate inference is given. libDAI is licensed under the GPL v2+ license and is available at © 2010.

Hong S.T.,Max Planck Institute for Biological Cybernetics
Magnetic resonance in medicine : official journal of the Society of Magnetic Resonance in Medicine / Society of Magnetic Resonance in Medicine | Year: 2011

Single voxel magnetic resonance spectroscopy with ultrashort echo time was implemented at 16.4 T to enhance the neurochemical profile of the rat brain in vivo. A TE of 1.7 msec was achieved by sequence optimization and by using short-duration asymmetric pulses. Macromolecular signal components were parameterized individually and included in the quantitative analysis, replacing the use of a metabolite-nulled spectrum. Because of the high spectral dispersion, several signals close to the water line could be detected, and adjacent peaks could be resolved. All 20 metabolites detected in this study were quantified with Cramér-Rao lower bounds below 20%, implying reliable quantification accuracy. The signal of acetate was detected for the first time in rat brain in vivo with Cramér-Rao lower bounds of 16% and a concentration of 0.52 μmol/g. The absolute concentrations of most metabolites showed close agreement with values previously measured using in vivo (1)H NMR spectroscopy and in vitro biochemical assay. © 2010 Wiley-Liss, Inc.

Panagiotaropoulos T.I.,Max Planck Institute for Biological Cybernetics
Philosophical transactions of the Royal Society of London. Series B, Biological sciences | Year: 2014

The combination of electrophysiological recordings with ambiguous visual stimulation made possible the detection of neurons that represent the content of subjective visual perception and perceptual suppression in multiple cortical and subcortical brain regions. These neuronal populations, commonly referred to as the neural correlates of consciousness, are more likely to be found in the temporal and prefrontal cortices as well as the pulvinar, indicating that the content of perceptual awareness is represented with higher fidelity in higher-order association areas of the cortical and thalamic hierarchy, reflecting the outcome of competitive interactions between conflicting sensory information resolved in earlier stages. However, despite the significant insights into conscious perception gained through monitoring the activities of single neurons and small, local populations, the immense functional complexity of the brain arising from correlations in the activity of its constituent parts suggests that local, microscopic activity could only partially reveal the mechanisms involved in perceptual awareness. Rather, the dynamics of functional connectivity patterns on a mesoscopic and macroscopic level could be critical for conscious perception. Understanding these emergent spatio-temporal patterns could be informative not only for the stability of subjective perception but also for spontaneous perceptual transitions suggested to depend either on the dynamics of antagonistic ensembles or on global intrinsic activity fluctuations that may act upon explicit neural representations of sensory stimuli and induce perceptual reorganization. Here, we review the most recent results from local activity recordings and discuss the potential role of effective, correlated interactions during perceptual awareness.

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