Andreas Wilmer


Institute of Psychology
Fliednerstrasse 21,
D-48149 Münster

Phone: +49 (0) 251 833 4175
Fax.: +49 (0) 251 833 4173
E-mail: andreas.wilmer@uni-muenster.de
Andreas-wilmer

Joined OCC in 2007

Research Project

Detecting Time-Dependent Functional Connectivity in Magnetoencephalography by Estimating Time-Delayed Phase Synchronization

A central issue in cognitive neuroscience is which cortical areas are involved in managing information processing in a cognitive task and to understand their temporal interactions. Since the transfer of information in the form of electrical activity from one cortical region will in turn evoke electrical activity in other regions, the analysis of temporal synchronization provides a tool to understand neuronal information processing between cortical regions. We adopt dedicated methods for revealing estimates on time-dependent functional connectivity on small data-sets as reliably as possible. The information flow between cortical regions is recovered by a statistical analyses of phases. Additionally, the embedding with a parametric time-delay allows a reconstruction of arbitrary non-stationary connective structures - so-called connectivity patterns - in a wide class of systems such as coupled oscillatory or even pure stochastic driven processes. Our approach needs no assumptions about coupling directions, delay times, temporal dynamics, nonlinearities or underlying mechanisms. Methods are refined on such synthetic systems with a-priori known connective structures. The compatibility to inverse techniques is verified on basis of dipole simulations. Finally, our method is applied on experimental magnetoencephalographic data.

Promotion Committee

Prof. Dr. Markus Lappe (Supervisor)
Prof. Dr. Christo Pantev
Prof. Dr. Norbert Sachser

Publications

A. Wilmer, M.H.E. de Lussanet, M. Lappe (2010). A method for the estimation of functional brain connectivity from time-series data. Cogn. Neurodyn. 4:133{149

A. Wilmer, T.D. Frank, P.J. Beek, R. Friedrich (2007). A data-analysis method for identifying differential effects of time-delayed feedback forces and periodic driving forces in stochastic systems. Eur. Phys. J. B 60:203{215

Conference Contributions

Cortical information transfer in MEG data - Measuring time - dependent functional connectivity.
Talk at the Institute of Cognitive Science, University of Osnabrück, Germany, 2010.

Cortical information transfer in MEG data - Measuring time - dependent functional connectivity.
Talk at the Department of Neurology and Clinical Neurophysiology, Charité, University Medicine Berlin, Germany, 2010.

A.Wilmer, M.H.E. de Lussanet, M. Lappe
Measuring functional connectivity by the estimation of the time-delayed mutual-
information of the phase.
Poster at the SfN, San Diego, USA, 2010.

Functional connectivity in brain - Measuring time - dependent flow of information.
Talk at the Institute for Biomagnetism and Biosignalanalysis, Münster, Germany, 2010.

A.Wilmer, M.H.E. de Lussanet, M. Lappe
Detection of synchronization: a method for revealing time dependent functional
cortical connectivity.
Poster at the Symposium `Fusing brain states and mental domains', Münster, Germany, 2008.

A. Wilmer, T.D. Frank, R. Friedrich (2006)
Data analysis of periodically forced stochastic systems with time delay.
Poster at the DPG Conference, Dresden, Germany, 2006.

CV

*1980 Vreden, Germany
 2000-2002 Studies in Technical Physics, Technical University Ilmenau
 2002-2006 Studies in Physics, Institute of Theoretical Physics, University of Münster
 2006 Diploma thesis (MSc), Institute for Theoretical Physics, University of Münster, (Supervisor: Prof. Dr. Friedrich)
 2006 Beginning of PhD research project, Institute of Psychology, University of Münster