EPICOG: Multi-level approach of human brain networks underlying epilepsy and cognition – EPICOG

In epilepsy surgery candidates, the identification of the cortical areas to be removed and the evaluation of their functional integrity is a difficult process which often requires intracranial EEG (iEEG) recordings. However, even when using iEEG information, epilepsy surgery fails in a substantial proportion of patients, and post-surgery cognitive deficits still exist in a significant number of cases.
The long-term objective of EPICOG is to better understand the relationships between the neuronal networks underlying epilepsy and cognition in the context of epilepsy surgery. To do so, we will focus on specific forms of epilepsies involving prefrontal and insular cortices and on decision-making processes likely to be involved in these forms of epilepsies. We will implement and use innovative multi-scale read-outs of epileptogenicity and cognition, and in particular pathological and physiological high-frequency activities. The single-cell correlates underlying these biomarkers will be deciphered thanks to the use of hybrid macro-micro depth electrodes, combining classic depth recording of iEEG and tetrodes enabling single-neurons to be recorded simultaneously. These tools will allow us to investigate interferences between pathological and physiological neural activities and to correlate these biomarkers to classical clinical tools used in epilepsy such as the visual inspection of iEEG signals, the effects of direct electrical stimulation, and post-surgery outcomes. This should help to answer important issues in this field, such as whether neural tissue that expresses epileptic neural activity remains partly functional or not, whether task-related neural activities are altered or not by epileptic activity, and whether the post-surgery removal of brain tissue might have clinically significant consequences on decision-making.