Are age-related cognitive effects caused by optimization? (2009)
Schrobsdorff, Hecke, Ihrke, Matthias, Behrendt, Jörg, Herrmann, J Michael, Geisel, Theo, Levina, Anna
On the temporal structure of correlated activity in a pair of neurons (2009)
Tchumatchenko, Tatjana, Malyshev, Aleksey, Geisel, Theo, Volgushev, Maxim, Wolf, Fred
No abstract available.
Switching to criticality by synchronized input (2009)
Levina, Anna, Geisel, Theo, Herrmann, J Michael
No abstract available.
First-to-fire neurons induced by clustering in sparse networks (2009)
Stetter, Olav, Levina, Anna, Geisel, Theo
No abstract available.
Abigail Morrison, Carsten Mehring, Theo Geisel, Ad Aertsen, Markus Diesmann
The availability of efficient and reliable simulation tools is one of the mission-critical technologies in the fast-moving field of computational neuroscience. Research indicates that higher brain...
Wavepacket dynamics in energy space of a chaotic trimeric Bose-Hubbard system (2009)
Hiller, Moritz, Kottos, Tsampikos, Geisel, Theo
We study the energy redistribution of interacting bosons in a ring-shaped quantum trimer as the coupling strength between neighboring sites of the corresponding Bose-Hubbard Hamiltonian undergoes a...
Quasi-Movements: A Novel Motor-Cognitive Phenomenon (2008)
Rd Bernstein Symposium, Theo Geisel, Chair Freiburg, Stefan Rotter, Marc Timme, Bccn Göttingen, ...
Reading hidden intentions in the human brain
zur Erlangung des Doktorgrades der Mathematisch-Naturwissenschaftlichen (2008)
Björn Naundorf, Referent Prof, Dr. Theo Geisel, Koreferent Prof, Dr. Reiner Kree
2.1 Single neurons as computational units......................... 11 2.2 Action potentials as general communication paradigm in the cortex.......... 12
Correlations and Synchrony in Threshold Neuron Models (2008)
Tchumatchenko, Tatjana, Malyshev, Aleksey, Geisel, Theo, Volgushev, Maxim, Wolf, Fred
We study how threshold model neurons transfer temporal and interneuronal input correlations to correlations of spikes. We find that the low common input regime is governed by firing rate dependent...
Sequential Desynchronization in Networks of Spiking Neurons with Partial Reset (2008)
Kirst, Christoph, Geisel, Theo, Timme, Marc
The response of a neuron to synaptic input strongly depends on whether or not it has just emitted a spike. We propose a neuron model that after spike emission exhibits a partial response to residual...
Alexander Hornstein, Referent Prof, Dr. Ulrich Parlitz, Korreferent Prof, Dr. Theo Geisel
Dynamical modeling with application to friction phenomena
The spread ofrate and correlation in stationary cortical (2008)
Tom Tetzla, Michael Buschermohle, Theo Geisel, Markus Diesmann
networks
Resulting fixpoints: ⋆ Periodic patterns ⋆ Localized solutions (2008)
J. Michael Herrmann, Hecke Schrobsdorff, Theo Geisel
We investigate analytically properties like stability and existence of solutions of the two dimensional neural field equation as proposed by Amari (1977) in [1] as a model of macroscopic activation...
Matthias Kaschube, Fred Wolf, Theo Geisel
Quantifying the variability of patterns of orientation domains in the visual cortex of cats
Dynamical Synapses Give Rise to a Power-Law Distribution of Neuronal Avalanches (2008)
Anna Levina, J. Michael Herrmann, Theo Geisel
There is experimental evidence that cortical neurons show avalanche activity with the intensity of firing events being distributed as a power-law. We present a biologically plausible extension of a...
Matthias Kaschube, Fred Wolf, Mathias Puhlmann, Stefan Rathjen, Karl-friedrich Schmidt, Theo Geisel, ...
The pattern of ocular dominance columns in cat primary
Hecke Schrobsdorff, J. Michael Herrmann, Theo Geisel
feature-binding model with localized excitations
Dynamical synapses causing self-organized criticality in neural networks (2007)
Levina, Anna, Herrmann, J. Michael, Geisel, Theo
We show that a network of spiking neurons exhibits robust self-organized criticality if the synaptic efficacies follow realistic dynamics. Deriving analytical expressions for the average coupling...
Signal Processing by Means of Noise (2007)
Noisy integrate-and-re neurons encode periodic signals best at a preferred noisefrequency combination. We show that the preferred frequency, optimum noise and optimum signal-to-noise ratio are...
Maximilian Riesenhuber, Hans-ulrich Bauer, Theo Geisel
. We present a method for calculating phase diagrams for the high-dimensional variant of the Self-Organizing Map (SOM). The method requires only an ansatz for the tesselation of the data space...
Quantum Chaos and Spectral Transitions in the Kicked Harper Model (2007)
Karsten Kruse, Roland Ketzmerick, Theo Geisel
. In contrast to bounded systems, quantum chaos in extended systems may be associated with fractal spectra, metal-insulator transitions due to avoided band crossings, and spreading wave packets. In...
Calculating Conditions For The Emergence Of Structure In Self-Organizing Maps (2007)
Hans-ulrich Bauer, Maximilian Riesenhuber, Theo Geisel
Introduction The self-organization of sensotopic maps in the brain has been modeled with various approaches, using models with linear [1, 2, 3, 4] and nonlinear [5, 6, 7] lateral interaction...
Klaus Pawelzik, Fred Wolf, Theo Geisel, Udo Ernst, Udo Ernst
Stimulation outside the classical receptive field can alter drastically the response properties of simple neurons. Besides the well known phenomena of patch-suppression and contrast enhancement,...
Fractal conductance fluctuations of classical origin (2007)
Hennig, Holger, Fleischmann, Ragnar, Hufnagel, Lars, Geisel, Theo
A feature-binding model with localized excitations (2007)
Schrobsdorff, Henning, Herrmann, Michael, Geisel, Theo
We study a model of feature binding in prefrontal cortex which defers pecific perceptual information to lower areas and merely maintains the identity of the combination. The model consists of three...
Timme, Marc, Geisel, Theo, Wolf, Fred
We analyze the dynamics of networks of spiking neural oscillators. First, we present an exact linear stability theory of the synchronous state for networks of arbitrary connectivity. For general...
Quantum decay of an open chaotic system: a semiclassical approach (2004)
Puhlmann, Mathias, Schanz, Holger, Kottos, Tsampikos, Geisel, Theo
We study the quantum probability to survive in an open chaotic system in the framework of the van Vleck-Gutzwiller propagator and present the first such calculation that accounts for quantum...
Long Chaotic Transients in Complex Networks (2004)
Zumdieck, Alexander, Timme, Marc, Geisel, Theo, Wolf, Fred
We show that long chaotic transients dominate the dynamics of randomly diluted networks of pulse-coupled oscillators. This contrasts with the rapid convergence towards limit cycle attractors found in...
Breaking synchrony by heterogeneity in complex networks (2004)
Denker, Michael, Timme, Marc, Diesmann, Markus, Wolf, Fred, Geisel, Theo
Breaking Synchrony by Heterogeneity in Complex Networks (2004)
Denker, Michael, Timme, Marc, Diesmann, Markus, Wolf, Fred, Geisel, Theo
Breaking Synchrony by Heterogeneity in Complex Networks (2003)
Denker, Michael, Timme, Marc, Diesmann, Markus, Wolf, Fred, Geisel, Theo
For networks of pulse-coupled oscillators with complex connectivity, we demonstrate that in the presence of coupling heterogeneity precisely timed periodic firing patterns replace the state of global...
Quantum Reversibility: Is there an Echo? (2003)
Hiller, Moritz, Kottos, Tsampikos, Cohen, Doron, Geisel, Theo
We study the possibility to undo the quantum mechanical evolution in a time reversal experiment. The naive expectation, as reflected in the common terminology ("Loschmidt echo"), is that maximum...
The Intrinsic Time Scale of Transient Neuronal Responses (2003)
Naundorf, Bjoern, Geisel, Theo, Wolf, Fred
In a generic neuron model, we present the linear response theory for the firing rate in response to both time dependent input currents and noise amplitudes. In both cases the signal transmission is...
Signatures of Classical Diffusion in Quantum Fluctuations of 2D Chaotic Systems (2003)
Kottos, Tsampikos, Ossipov, Alexander, Geisel, Theo
We consider a two-dimensional (2D) generalization of the standard kicked-rotor (KR) and show that it is an excellent model for the study of 2D quantum systems with underlying diffusive classical...
Topological Speed Limits to Network Synchronization (2003)
Timme, Marc, Wolf, Fred, Geisel, Theo
We study collective synchronization of pulse-coupled oscillators interacting on asymmetric random networks. We demonstrate that random matrix theory can be used to accurately predict the speed of...
Shot noise from action correlations (2003)
Schanz, Holger, Puhlmann, Mathias, Geisel, Theo
We consider universal shot noise in ballistic chaotic cavities from a semiclassical point of view and show that it is due to action correlations within certain groups of classical trajectories. Using...
Unstable attractors induce perpetual synchronization and desynchronization (2002)
Timme, Marc, Wolf, Fred, Geisel, Theo
Common experience suggests that attracting invariant sets in nonlinear dynamical systems are generally stable. Contrary to this intuition, we present a dynamical system, a network of pulse-coupled...
Timme, Marc, Wolf, Fred, Geisel, Theo
For general networks of pulse-coupled oscillators, including regular, random, and more complex networks, we develop an exact stability analysis of synchronous states. As opposed to conventional...
Prevalence of unstable attractors in networks of pulse-coupled oscillators (2002)
Timme, Marc, Wolf, Fred, Geisel, Theo
We present and analyze the first example of a dynamical system that naturally exhibits attracting periodic orbits that are \textit{unstable}. These unstable attractors occur in networks of...
Timme, Marc, Wolf, Fred, Geisel, Theo
For general networks of pulse-coupled oscillators, including regular, random, and more complex networks, we develop an exact stability analysis of synchronous states. As opposed to conventional...
Prevalence of unstable attractors in networks of pulse-coupled oscillators (2002)
Timme, Marc, Wolf, Fred, Geisel, Theo
We present and analyze the first example of a dynamical system that naturally exhibits attracting periodic orbits that are unstable. These unstable attractors occur in networks of pulse-coupled...
The Ground State of Cortical Feed-Forward (2002)
Networks Tom Tetzla, Tom Tetzla, Theo Geisel, Markus Diesmann
The occurrence of spatio-temporal spike patterns in the cortex is explained by models of divergent/convergent feed-forward subnetworks -- synfire chains. Their excited mode is characterized by spike...
Genetic influence on quantitative features of neocortical architecture (2002)
Matthias Kaschube, Fred Wolf, Theo Geisel, Siegrid Löwel
The layout of functional cortical maps exhibits a high degree of interindividual variability that may account for individual differences in sensory and cognitive abilities. By quantitatively...
Stimulus-independent data analysis of fMRI data (2001)
Silke Dodel, J. Michael Herrmann, Theo Geisel
this paper. Fig. 1 shows 4 PCS containing the highest amount of the fingertapping cycle frequency of 0.025 Hz. The courves on the right hand side give the time course and the power spectral density...
Stimulus-independent data analysis for fMRI (2001)
Silke Dodel, J. Michael Herrmann, Theo Geisel
Functional Magnetic Resonance Imaging (fMRI) is a promising method to determine noninvasively the spatial distribution of brain activity under a given paradigm, e.g. in response to certain stimuli....
Spreading and localization of wavepackets in disordered wires in a magnetic field (2000)
Weiss, Matthias, Kottos, Tsampikos, Geisel, Theo
We study the diffusive and localization properties of wavepackets in disordered wires in a magnetic field. In contrast to a recent supersymmetry approach our numerical results show that the decay...
Weiss, Matthias, Kottos, Tsampikos, Geisel, Theo
We investigate the scaling properties of eigenstates of a one-dimensional (1D) Anderson model in the presence of a constant electric field. The states show a transition from exponential to factorial...
Stochastic Resonance in Neuron Models: Endogenous Stimulation Revisited (2000)
Plesser, Hans E., Geisel, Theo
The paradigm of stochastic resonance (SR)---the idea that signal detection and transmission may benefit from noise---has met with great interest in both physics and the neurosciences. We investigate...
Signal Selection Based on Stochastic Resonance (2000)
Plesser, Hans E., Geisel, Theo
Noise aids the encoding of continuous signals into pulse sequences by way of stochastic resonance and endows the encoding device with a preferred frequency. We study encoding by a threshold device...
Quantifying the Variability of Patterns of Orientation Domains in the Visual Cortex of Cats (2000)
Matthias Kaschube, Fred Wolf, Theo Geisel, Siegrid Löwel
In the visual cortex of cats, orientation patterns vary considerably among dierent individuals. In present, it is unclear whether this variability is due to environmental inuence, if it is induced by...
Norbert Mayer, J. Michael Herrmann, Theo Geisel, Kenneth D. Miller
Abstract. We present a computational study of the formation of simple-cell receptive field patterns in the primary visual cortex. Based on the observation that the spatial frequency of the retinal...
The ecology of gaze shifts (2000)
We present a phenomenological model for the generation of human visual scanpaths. Successions of saccadic eye movements are treated as realizations of a stochastic jump process in a random quenched...
Hans Ekkehard Pleßer, Referent Prof, Dr. Theo Geisel, Korreferent Prof, Dr. Reiner Kree, Signalverarbeitung In Neuronen
zu kommunizieren und schließlich uns selbst als Denkende zu reflektieren. Auch die glänzendsten Erfolge der künstlichen Intelligenz, wie der Sieg des Schachcomputers Deep Blue über Weltmeister...
Brief Pauses as Signals for Depressing Synapses (1999)
Matthias Bethge, Klaus Pawelzik, Theo Geisel
Activity-dependent synaptic depression is a striking feature of synaptic transmission between neocortical pyramidal neurons. It has been shown that this kind of synaptic dynamics permits the...
The Ecology of Gaze Shifts (1999)
We present a phenomenological model for the generation of human visual scanpaths. Successions of saccadic eye-movements are treated as realizations of a stochastic jump process in a random quenched...
Bandpass Properties of Integrate-Fire Neurons (1999)
There is mounting experimental evidence that the nervous system utilizes neural noise to improve sensory signal transmission. Here, we investigate the response properties of a noisy neuron using an...
Corresponding author. Tel.: 49-421-218-3645; fax: 49-421-218-9104. (1999)
Mail Address Pawelzik, Matthias Bethge, Klaus Pawelzik, Theo Geisel
Activity-dependent synaptic depression is a striking feature of synaptic transmission between neocortical pyramidal neurons. It has been shown that this kind of synaptic dynamics permits the...
Markov analysis of stochastic resonance in a periodically driven integrate-fire neuron (1998)
Plesser, Hans E., Geisel, Theo
We model the dynamics of the leaky integrate-fire neuron under periodic stimulation as a Markov process with respect to the stimulus phase. This avoids the unrealistic assumption of a stimulus reset...
Dirk Brockmann, Maximilian Riesenhuber, Hans-ulrich Bauer, Theo Geisel
: We investigate a model for the joint development of orientation and ocular dominance columns which is based on the high-dimensional version of Kohonen's Self-Organizing Map algorithm. The...
Orientation Contrast Sensitivity From Long-Range Interactions in Visual Cortex (1996)
Klaus R. Pawelzik, Udo Ernst, Fred Wolf, Theo Geisel
Recently Sillito and coworkers (Nature 378, pp. 492, 1995) demonstrated that stimulation beyond the classical receptive field (cRF) can not only modulate, but radically change a neuron's...
Maximilian Riesenhuber, Hans-ulrich Bauer, Theo Geisel
Introduction The self-organization of sensotopic maps, in particular of visual maps, continues to be an area of great interest in computational neuroscience. In order to distinguish between the...
Maximilian Riesenhuber, Hans-ulrich Bauer, Theo Geisel
Introduction The self-organization of sensotopic maps, in particular of visual maps, continues to be an area of great interest in computational neuroscience. In order to distinguish between the...
Theorie der Ramanstreuung in den Ammoniumhalogeniden / (1975)
Regensburg, Univ., Diss., 1975.