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Speaker: Jos Roerdink (Bernoulli Institute for Mathematics, Computer Science and Artificial Intelligence, University of Groningen)
Title: "Data-Driven Visualization of Multichannel EEG Coherence with Functional Units"
When: Thu 29 Jun, 9:30-10:30
Where: SR 7, Währinger Straße 29, 1st floor
 
Abstract: A typical data-driven visualization of electroencephalography (EEG) coherence is a graph layout, with vertices representing electrodes and edges representing significant coherences between electrode signals. To reduce clutter, the concept of functional unit (FU) was introduced as a data-driven region of interest (ROI). To detect FUs, we developed a maximal clique-based method, which is very time consuming, and a much more efficient watershed-based greedy method, thus making interactive visualization of multichannel EEG coherence possible. Group mean coherence maps enable group comparisons. The visualization of (group) FU maps provides a very economical data summary of large amounts of experimental data. The method was applied to case studies on ageing and mental fatigue [1], and can be extended to deal with the case that coherence networks evolve over time [2].
 
References:
[1] M. ten Caat, N.M. Maurits, and J.B.T.M. Roerdink. Data-driven visualization and group analysis of multichannel EEG coherence with functional units.  IEEE Trans. Visualization and Computer Graphics 14(4), 756-771, 2008.
[2] C. Ji, J.J. van de Gronde, N.M. Maurits, and J.B.T.M. Roerdink. Visual Exploration of Dynamic Multichannel EEG Coherence Networks. Computer Graphics Forum 38(1), 507-520, 2019.
 
Bio: Jos Roerdink studied biology and physics at the University of Nijmegen, the Netherlands. In 1983 he obtained his PhD in statistical physics at the University of Utrecht. After a 2-year postdoctoral stay
at the University of California, San Diego, he joined the Centre for Mathematics and Computer Science in Amsterdam, where he started work on image processing and reconstruction. In 1991 he became associate professor at the University of Groningen. In 2003 he was appointed as full professor at the same university with a chair in Scientific Visualization and Computer Graphics, with a secondary appointment at the Neuroimaging Center of the University Medical Center Groningen. He was director of the Johann Bernoulli Institute for Mathematics and Computer Science from 2015-2017, and from 2018-2020 he was director of the newly formed Bernoulli Institute for Mathematics, Computer Science and Artificial Intelligence. Since January 1, 2021, he is emeritus professor of the University of Groningen.