Face-name associative memory in temporal lobe epilepsy: Region-specific insights in right-hemisphere onset

Mapping memory function in temporal lobe epilepsy (TLE) is important for understanding surgical risk, yet practical noninvasive tools remain limited. We tested whether a face-name associative memory fMRI task could detect subregional dysfunction within the amygdala-hippocampal complex (AHC) in TLE. Forty-nine individuals with unilateral TLE (29 left-, 20 right-onset; 51% MTS-negative) and 25 controls from three centers were scanned during a face-name encoding task and completed delayed recognition and neuropsychological tests of memory. The hippocampal head, body, tail, and amygdala were anatomically segmented, and activation was examined for encoding and novelty contrasts. In controls, AHC activation was predominantly right-lateralized. For encoding, a Region × Hemisphere × Group interaction showed reduced ipsilateral amygdala and hippocampal tail activation in right TLE, with relative preservation in other subregions. Left TLE showed a nonsignificant medium effect in the ipsilateral amygdala. In right TLE, greater contralateral amygdala activation correlated with better face-name recognition and verbal memory, while greater ipsilateral hippocampal tail activation correlated with better verbal and visual memory. Findings were independent of mesial temporal sclerosis and hippocampal volume. A brief, ecologically valid face-name fMRI task revealed lateralized, subregion-specific disruption in right TLE and behaviorally relevant variability in the amygdala and posterior hippocampal engagement. Future work is needed to determine whether these activation patterns predict post-surgical memory outcomes.