PUB - Publikationen an der Universität Bielefeld

OBJECTIVE: Neuroimaging studies reveal frontal lobe contributions to memory encoding. Accordingly, memory impairments are documented in frontal lobe epilepsy (FLE). Still, little is known about the structural or functional correlates of such impairments. Particularly, material specificity of functional changes in cerebral activity during memory encoding in FLE is unclear.; METHODS: We compared 24 FLE patients (15 right-sided) undergoing pre-surgical evaluation with 30 healthy controls on a memory fMRI-paradigm of learning scenes, faces, and words followed by an out-of-scanner recognition task as well as regarding their mesial temporal volumes. We also addressed effects of FLE lateralization and performance level (normal versus low).; RESULTS: FLE patients had poorer memory performance and larger left hippocampal volumes than controls. Volume increase seemed, however, irrelevant or even dysfunctional for memory performance. Further, functional changes in FLE patients were right-sided for scenes and faces and bilateral for words. In detail, during face encoding, FLE patients had, regardless of performance level, decreased mTL activation, whilst during scene and word encoding only low performing FLE patients had decreased mTL along with decreased frontal activation. Intact verbal memory performance was associated with higher right frontal activation in FLE patients but not in controls.; SIGNIFICANCE: Pharmacoresistant FLE has a distinct functional and structural impact on the mTL. Effects vary with the encoded material and patients' performance levels. Thus, in addition to the direct effect of the frontal lobe, memory impairment in FLE is presumably to a large part due to functional mTL changes triggered by disrupted frontal lobe networks. This article is protected by copyright. All rights reserved.