Séminaire COSY : " Understanding human face perception using intracerebral recordings and electrical stimulation ".

Ce séminaire (invitation) se déroulera dans la salle de séminaire MARTIN V 42B, de 12h30 à 13h30 sur le campus de Louvain-en-Woluwe (UCL) et s'inscrit dans le cadre du cycle de séminaires 2014-2015 organisé par le pôle COSY.

ABSTRACT : recognizing people by their face is an extremely important function of the human brain, critical for social interactions. This ability depends on a large network of brain regions distributed along the ventral visual pathway (i.e., from the occipital lobe to the temporal pole). However, outstanding questions remain unsolved, such as which of these brain regions are critical for face perception (i.e., which regions perform face recognition). To this end, we use depth electrodes implanted in patients’ brains that allow performing electrical stimulations and neurophysiological recordings of the human cortex. I will present several studies showing that face recognition can be transiently and selectively inactivated by electrically stimulating specific brain regions. Patients were either unable to recognize famous faces, unable to discriminate between two different facial identities or reported hallucinations of faces that mix different facial identities. Independent intracerebral EEG recordings coupled with a periodic visual presentation paradigm reveal that these stimulated regions were the most sensitive to face identity. Taken together, these studies show the causal role of specific cortical regions in face recognition and illustrate the functional value of the periodic visual presentation approach. More generally, these studies provide a rare causal link between specific brain regions and visual perception.

Jacques Jonas, MD, is currently PhD student (aspirant FNRS) in the face categorization lab (Bruno Rossion, UCL). He is a neurologist working in the field of epilepsy, with a specific interest in the pre-surgical evaluation of refractory focal epilepsy using intracerebral recordings (CHU Nancy, France). His research interests concern the understanding of visual functions using intracerebral recordings and intracerebral electrical stimulations. My PhD project is focused on the investigation of face perception in Humans using intracerebral recordings coupled with the periodic visual presentation approach (steady-state visual evoked potentials).