Affiliations: INSERM, U751, Laboratoire de Neurophysiologie et
Neuropsychologie, Marseille, F-13005, France | Université de la Méditerranée, Faculté
de Médecine, Marseille, F-13005 France | CHU Timone, Service de Neurophysiologie Clinique,
Assistance Publique des Hôpitaux de Marseille, Marseille, F-13005, France | AP-HP, Groupe hospitalier
Pitié-Salpêtrière, Departments of Neurophysiology &
Neurology, Paris, France | INSERM, ICM Research Center, UMRS 975, Paris,
France | Université Paris 6, Faculté de Médecine
Pitié-Salpêtrière, Paris, France
Note: [] Corresponding author: Pr Fabrice Bartolomei, MD, PhD, Service de
Neurophysiologie Clinique, CHU Timone-264 Rue st Pierre, 13005-Marseille,
France. Tel.: +33 491 385 833; Fax: +33 491 385 826; E-mail: fabrice.bartolomei@ap-hm.fr
Abstract: The global workspace (GW) theory proposes that conscious processing
results from coherent neuronal activity between widely distributed brain
regions, with fronto-parietal associative cortices as key elements. In this
model, transition between conscious and non conscious states are predicted to
be caused by abrupt non-linear massive changes of the level of coherence within
this distributed neural space. Epileptic seizures offer a unique model to
explore the validity of this central hypothesis. Seizures are often
characterized by the occurrence of brutal alterations of consciousness (AOC)
which are largely negatively impacting patients' lives. Recently, we have shown
that these sudden AOC are contemporary to non-linear increases of neural
synchrony within distant cortico-cortical and cortico-thalamic networks. We
interpreted these results in the light of GW theory, and suggested that
excessive synchrony could prevent this distributed network to reach the minimal
level of differentiation and complexity necessary to the coding of conscious
representations. These observations both confirm some predictions of the GW
model, and further specify the physiological window of neural coherence
(minimum and maximum) associated with conscious processing.
Keywords: Consciousness, temporal lobe epilepsy, global workspace, synchrony
