Atlas of Human Cognition by SEEG (MAPCOG-SEEG)

The pre-surgical assessment of a cortectomy in patient suffering from a refractory epilepsy includes several examinations aiming both, to specify the epileptogenic zone (EZ) which must be resected and to evaluate functional and cognitive risks of surgery.

Nevertheless, in some patients, non-invasive evaluation does not give formal answer. In these subjects, it is then necessary to carry out a second step, consisting of an invasive exploration by implantation of intracerebral electrodes during a Stereoelectroencephalography (SEEG).

Due to its temporal and spatial resolution, the SEEG allows, besides the precise determination of the EZ, to carry out a functional mapping of the cortical regions likely to be included in cortectomy. Conventionally, this mapping is carried out on the basis of the cortical electrical stimulations applied to the implanted electrodes. If this approach is very robust for exploring primary functions such as motor skills or language, it cannot be used to evaluate more complex cognitive tasks such as face recognition or attention. Essential cognitive tasks on a daily basis.

This has led to the development in recent years, in Grenoble, of a complementary approach to cerebral stimulation: Dynamic Spectral Imaging (ISD). Numerous experimental paradigms have demonstrated that the realization of a cognitive task associates with the generation within the cortical regions involved in its treatment of a particular cortical activity. This activity is characterized by oscillations of the cortical rhythm in high frequencies (> 40 Hz), called gamma activities. The ISD thus consists in mapping this gamma activity during various cognitive tasks, thus making it possible to study more widely the complexity of the cognitive functions.

MAPCOG_SEEG aims to collect the cerebral recording of the patients who have performed this cognitive exploration to be able to in fine propose an Atlas of human cognition which takes advantage of the very rich information in terms of spatial and temporal resolution of the SEEG. Furthermore, it will exactly allow more to understand the impact of the epilepsy and the surgery of the epilepsy on the cognition.