Authors :
Presenting Author: Alena Stasenko, PhD – UC San Diego
Adam Schadler, MS – UC San Diego
Erik Kaestner, PhD – UC San Diego
Evan Brady, BS – Emory University School of Medicine
Daniel Drane, PhD – Emory University School of Medicine
Christine Smith, PhD – UC San Diego
Taha Gholipour, MD – UC San Diego
Carrie McDonald, PhD – UC San Diego
Rationale:
Mapping memory is important for surgical planning in temporal lobe epilepsy (TLE), yet clinically reliable non-invasive tools remain limited. We tested whether a face-name associative memory fMRI task could detect hemispheric- and subregion-specific disruptions in the amygdala-hippocampal complex (AHC) in TLE, beyond structural volume.
Methods:
Forty-nine individuals with unilateral TLE (29 left-, 20 right-onset; 51% non-lesional) and 25 controls underwent task-based fMRI across three surgical centers. Participants performed a face-name encoding task followed by delayed recognition and completed standardized verbal and visuospatial memory tests. The hippocampal head, body, tail, and amygdala were anatomically segmented. Activation for encoding and novelty effects was examined and related to out-of-scanner memory performance.Results:
Controls showed predominantly right-lateralized AHC activation for both contrasts. For the encoding effect, a significant Region x Hemisphere x Group interaction (ηp2 = .08) revealed reduced right amygdala and hippocampal tail activation in right TLE, whereas left TLE showed only a nonsignificant medium effect in the left amygdala. About one-third of right TLE patients showed “control-like” right amygdala activation and performed better on face–name recognition. In right TLE, greater left amygdala activation correlated with better face-name recognition (r = .64) and verbal memory (rs = .45-.61), while greater right hippocampal tail activation correlated with better verbal and visual memory (rs = .53). Findings were independent of mesial temporal sclerosis and hippocampal volume.
Conclusions:
Face-name encoding fMRI revealed lateralized and subregion-specific disruptions in right TLE, underscoring the functional relevance of the amygdala and hippocampal tail—regions often overlooked in presurgical mapping. Recruitment of contralateral amygdala and ipsilateral hippocampal tail may provide functional reserve when ipsilateral anterior structures are compromised. These effects, observed even in non-lesional cases, support the potential of associative memory fMRI to inform individualized, function-sparing neurosurgery, pending validation against post-operative outcomes.
Funding:
R01NS12458