title: Delayed verbal memory retrieval: a functional MRI study in epileptic patients with structural lesions of the left medial temporal lobe.
abstract: In a previous functional magnetic resonance imaging (fMRI) study, we suggested that in left medial temporal lobe epilepsy (LTLE) poor verbal episodic memory performances were sustained by abnormal neocortical and mesiotemporal activations. In the present study, we attempted to examine the evolution of these abnormal neocortical and mesiotemporal activations over 24 h. We thus observed the fMRI brain regions activated during the 24-h-delayed retrieval of a word list in the same sample of healthy control subjects and LTLE patients. In control subjects, a similar left occipitotemporofrontal network was activated during both immediate and 24-h-delayed retrieval conditions. In addition, the 24-h-delayed retrieval also activated a larger parietal region and the right hippocampus. This distributed neocortical and mesiotemporal network was very poorly activated during the 24-h-delayed retrieval in LTLE patients, suggesting the inability to reactivate areas that are keys to retrieving stored information.
authors.affiliation: Unité d'Epileptologie, CNRS UPR640, Paris, France.
authors.forename: S
authors.initials: S
authors.lastname: Dupont
authors.forename: Y
authors.initials: Y
authors.lastname: Samson
authors.forename: P F
authors.initials: PF
authors.lastname: Van de Moortele
authors.forename: S
authors.initials: S
authors.lastname: Samson
authors.forename: J B
authors.initials: JB
authors.lastname: Poline
authors.forename: C
authors.initials: C
authors.lastname: Adam
authors.forename: S
authors.initials: S
authors.lastname: Lehéricy
authors.forename: D
authors.initials: D
authors.lastname: Le Bihan
authors.forename: M
authors.initials: M
authors.lastname: Baulac
mesh_terms: D000293:Adolescent; D000328:Adult; D001931:Brain Mapping; D004292:Dominance, Cerebral / Q000502:physiology*; D004833:Epilepsy, Temporal Lobe / Q000175:diagnosis / Q000503:physiopathology*; D005260:Female; D006624:Hippocampus / Q000503:physiopathology; D006801:Humans; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D008297:Male; D011939:Mental Recall / Q000502:physiology*; D008875:Middle Aged; D019579:Neocortex / Q000503:physiopathology; D009415:Nerve Net / Q000503:physiopathology; D009778:Occipital Lobe / Q000503:physiopathology; D012153:Retention, Psychology / Q000502:physiology; D013702:Temporal Lobe / Q000503:physiopathology; D014706:Verbal Learning / Q000502:physiology*