Schedule of Events | Symposia

Neural bases of the bodily self revealed by electrical brain stimulation in 354 epileptic patients

Poster Session F - Tuesday, April 1, 2025, 8:00 – 10:00 am EDT, Back Bay Ballroom/Republic Ballroom

Zoé Dary^1,5 (zdary@bwh.harvard.edu), Stanilas Lagarde^2,3, Samuel Medina Villalon^2,3, Hugo Dary⁴, Elodie Garnier³, Jacques Léonard⁵, Fabrice Bartolomei^2,3, Christophe Lopez⁵; ¹Department of Neurosurgery, Brigham and Women’s Hospital, Harvard Medical School, Boston, USA, ²INS, Institut de Neurosciences des Systèmes, Aix Marseille University, INSERM, Marseille, France, ³Epileptology and Cerebral Rhythmology Department, APHM, Timone Hospital, Marseille, France, ⁴Center for Magnetic Resonance in Biology and Medicine (CRMBM), CEMEREM, CHU, APHM, Timone Hospital, Marseille, France, ⁵Aix Marseille Univ, CNRS, Centre de Recherche en Psychologie et Neurosciences (CRPN), Marseille, France

The bodily self, a minimal form of self, is based on bodily experiences like self-location, ownership, agency, and first-person perspective. The network underlining these bodily self experiences has been studied using fMRI during multisensory illusions in healthy participants and through lesion analysis in neurological patients. Intracranial electrical stimulation in patients with epilepsy is another valuable method for brain mapping, linking bodily self changes to specific brain regions. In this study, we analysed clinical manifestations induced by direct electrical stimulation in 354 epilepsy patients undergoing stereo-encephalography (SEEG) for presurgical evaluation (2000–2021). Across 11,004 electrical stimulations, 2,320 clinical responses were recorded. Our analysis focused on bodily self disturbances. We identified 50 patients reporting bodily self disturbances in 78 stimulations (3.3% of all responses). Altered experiences included body image (n=29), depersonalization (n=23), self-location (n=17), and agency (n=15). These disturbances were linked to the anterior and posterior cingulate cortex, insula, supplementary motor area (SMA), precuneus, parietal operculum, and amygdalo-hippocampal complex. The functional connectivity results, across all experiences, showed a decrease in the strength of the inferior parietal lobule and the inferior temporal gyrus, suggesting a disconnection of these nodes in the bodily self network. The analysis of link strength revealed a decrease in functional connectivity between the inferior parietal lobule and the middle temporal gyrus, suggesting a functional decoupling between the bodily self and higher-order self-processing. These findings extend our understanding of the neural basis of the bodily self with another functional mapping technique than fMRI, which links specific areas to bodily precepts.

Topic Area: PERCEPTION & ACTION: Other