Spatial extension of brain activity fools the single-channel reconstruction of EEG dynamics

• Published in: Human brain mapping Vol. 5; no. 1; pp. 26 - 47
• Main Authors: Lachaux, Jean-Philippe, Pezard, Laurent, Garnero, Line, Pelte, Christophe, Renault, Bernard, Varela, Francisco J., Martinerie, Jacques
• Format: Journal Article
• Language: English
• Published: New York John Wiley & Sons, Inc 1997; Wiley-Liss
• Subjects: Biological and medical sciences; correlation dimension; coupled map lattices; EEG; Electrodiagnosis. Electric activity recording; Investigative techniques, diagnostic techniques (general aspects); Medical sciences; multichannel reconstruction; Nervous system; nonlinear dynamics; single-channel reconstruction; spatially extended systems; spatiotemporal chaos; Human; Reconstruction; Electrodiagnosis; Multichannel recording; Computer simulation; Exploration; Electroencephalography; Method; Comparative study
• ISSN: 1065-9471; 1097-0193
• DOI: 10.1002/(SICI)1097-0193(1997)5:1<26::AID-HBM4>3.0.CO;2-P

We report here on a first attempt to settle the methodological controversy between advocates of two alternative reconstruction approaches for temporal dynamics in brain signals: the single‐channel method (using data from one recording site and reconstructing by time‐lags), and the multiple‐channel method (using data from a spatially distributed set of recordings sites and reconstructing by means of spatial position). For the purpose of a proper comparison of these two techniques, we computed a series of EEG‐like measures on the basis of well‐known dynamical systems placed inside a spherical model of the head. For each of the simulations, the correlation dimension estimates obtained by both methods were calculated and compared, when possible, with the known (or estimated) dimension of the underlying dynamical system. We show that the single‐channel method fails to reliably quantify spatially extended dynamics, while the multichannel method performs better. It follows that the latter is preferable, given the known spatially distributed nature of brain processes. Hum. Brain Mapping 5:26–47, 1997. © 1997 Wiley‐Liss, Inc.