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.
Highlights
Epilepsy is one of the most frequent brain disease affecting near 1% of the general population and negatively impacting quality of life [28].There is a classical and operative distinction between generalized epilepsies in which the epileptic process affect bilaterally and widely the cerebral cortex and partial seizures in which the seizures start from a limited part of the cerebral cortex and secondarily spread to other cortical and subcortical regions
In this review we will focus on the mechanisms leading to Alteration of consciousness (AOC) in partial seizures, and in the most frequent type of chronic drug resistant partial epilepsies, the temporal lobe epilepsies (TLE)
We have proposed that AOC in temporal lobe seizures could be explained by an alteration of the “global workspace” functioning [3,13,17], a theory that we will developed in the paragraphs
Summary
Epilepsy is one of the most frequent brain disease affecting near 1% of the general population and negatively impacting quality of life [28]. There is a classical and operative distinction between generalized epilepsies in which the epileptic process affect bilaterally and widely the cerebral cortex and partial (or focal) seizures in which the seizures start from a limited part of the cerebral cortex and secondarily spread to other cortical and subcortical regions. In this review we will focus on the mechanisms leading to AOC in partial seizures, and in the most frequent type of chronic drug resistant partial epilepsies, the temporal lobe epilepsies (TLE). We have proposed that AOC in temporal lobe seizures could be explained by an alteration of the “global workspace” functioning [3,13,17], a theory that we will developed in the paragraphs
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