Hippocampal subfields sampled in human SEEG recordings
Abstract number :
3.037
Submission category :
1. Basic Mechanisms / 1C. Electrophysiology/High frequency oscillations
Year :
2025
Submission ID :
46
Source :
www.aesnet.org
Presentation date :
12/8/2025 12:00:00 AM
Published date :
Authors :
Presenting Author: George Plummer, MD – Massachusetts General Hospital
Dhinakaran Chinappen, PhD, MBA – Massachusetts General Hospital
Jordan Farrell, PhD – Stanford University
Catherine Chu, MD, MSC – Massachusetts General Hospital, Harvard Medical School, Kennedy Krieger Institute, Johns Hopkins University
Rationale: The hippocampus is a highly organized and evolutionarily conserved brain structure critical for learning and memory. The hippocampus’ laminar structure is organized into a well-delineated trisynaptic circuit spanning distinct subfields. Neural activity within each hippocampal subfield has also been linked to different memory functions. Although the human hippocampus is routinely sampled during intracranial SEEG recordings in patients with drug refractory epilepsy, the regions and subfields assayed are not typically distinguished in neurophysiological interpretation or analysis.
Methods: We localized the contacts from clinical SEEG electrodes targeting the hippocampus in consecutive patients that had consented to a memory experiment. All contacts on electrodes targeting hippocampi were manually marked after co-registration of the post-operative CT with MRI. They were then automatically localized to hippocamus and subfields using FreeSurfer. The proportion of contacts in anterior (MNI Y > -22) and posterior (MNI Y < -22) hippocampus, and in each hippocampal subfield was computed per patient. Localization agreement between visual inspection and FreeSurfer whole brain segmentation or hippocampal segmentation approaches was computed using Cohen’s Kappa.
Basic Mechanisms