Functional Unit Maps for Data-Driven Visualization of High-Density EEG Coherence
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Date
2007
Journal Title
Journal ISSN
Volume Title
Publisher
The Eurographics Association
Abstract
Synchronous electrical activity in different brain regions is generally assumed to imply functional relationships between these regions. A measure for this synchrony is electroencephalography (EEG) coherence, computed between pairs of signals as a function of frequency. Existing high-density EEG coherence visualizations are generally either hypothesis-driven, or data-driven graph visualizations which are cluttered. In this paper, a new method is presented for data-driven visualization of high-density EEG coherence, which strongly reduces clutter and is referred to as functional unit (FU) map. Starting from an initial graph, with vertices representing electrodes and edges representing significant coherences between electrode signals, we define an FU as a set of electrodes represented by a clique consisting of spatially connected vertices. In an FU map, the spatial relationship between electrodes is preserved, and all electrodes in one FU are assigned an identical gray value. Adjacent FUs are visualized with different gray values and FUs are connected by a line if the average coherence between FUs exceeds a threshold. Results obtained with our visualization are in accordance with known electrophysiological findings. FU maps can be used as a preprocessing step for conventional analysis.
Description
@inproceedings{:10.2312/VisSym/EuroVis07/259-266,
booktitle = {Eurographics/ IEEE-VGTC Symposium on Visualization},
editor = {K. Museth and T. Moeller and A. Ynnerman},
title = {{Functional Unit Maps for Data-Driven Visualization of High-Density EEG Coherence}},
author = {Caat, Michael ten and Maurits, Natasha M. and Roerdink, Jos B. T. M.},
year = {2007},
publisher = {The Eurographics Association},
ISSN = {1727-5296},
ISBN = {978-3-905673-45-6},
DOI = {/10.2312/VisSym/EuroVis07/259-266}
}