Computational and Mathematical Methods in Medicine
Volume 2012 (2012), Article ID 912729, 8 pages
Research Article

Fundamental Dynamical Modes Underlying Human Brain Synchronization

Centre de Recherche de l'Institut du Cerveau et de la Moelle Épinière (CRICM), INSERM, UMRS 975 and CNRS UMR 7225, UPMC, Hôpital de la Pitié-Salpêtrière, 75651 Paris cedex 13, France

Received 19 November 2011; Revised 15 January 2012; Accepted 1 March 2012

Academic Editor: Ralph G. Andrzejak

Copyright © 2012 Catalina Alvarado-Rojas and Michel Le Van Quyen. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Little is known about the long-term dynamics of widely interacting cortical and subcortical networks during the wake-sleep cycle. Using large-scale intracranial recordings of epileptic patients during seizure-free periods, we investigated local- and long-range synchronization between multiple brain regions over several days. For such high-dimensional data, summary information is required for understanding and modelling the underlying dynamics. Here, we suggest that a compact yet useful representation is given by a state space based on the first principal components. Using this representation, we report, with a remarkable similarity across the patients with different locations of electrode placement, that the seemingly complex patterns of brain synchrony during the wake-sleep cycle can be represented by a small number of characteristic dynamic modes. In this space, transitions between behavioral states occur through specific trajectories from one mode to another. These findings suggest that, at a coarse level of temporal resolution, the different brain states are correlated with several dominant synchrony patterns which are successively activated across wake-sleep states.