title: Human amnesia and the medial temporal lobe illuminated by neuropsychological and neurohistological findings for patient E.P.
abstract: We present neurohistological information for a case of bilateral, symmetrical damage to the medial temporal lobe and well-documented memory impairment. E.P. developed profound memory impairment at age 70 y and then was studied for 14 y He had no capacity for learning facts and events and had retrograde amnesia covering several decades. He also had a modest impairment of semantic knowledge. Neurohistological analysis revealed bilaterally symmetrical lesions of the medial temporal lobe that eliminated the temporal pole, the amygdala, the entorhinal cortex, the hippocampus, the perirhinal cortex, and rostral parahippocampal cortex. The lesion also extended laterally to involve the fusiform gyrus substantially. Last, the superior, inferior, and middle temporal gyri were atrophic, and subjacent white matter was gliotic. Several considerations indicate that E.P.'s severe memory impairment was caused by his medial temporal lesions, whereas his impaired semantic knowledge was caused by lateral temporal damage. His lateral temporal damage also may have contributed to his extensive retrograde amnesia. The findings illuminate the anatomical relationship between memory, perception, and semantic knowledge.
authors.affiliation: Department of Psychiatry and Behavioral Sciences and the Medical Investigation of Neurodevelopmental Disorders Institute, University of California at Davis, Sacramento, CA 95817, USA.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Insausti
authors.forename: Jacopo
authors.initials: J
authors.lastname: Annese
authors.forename: David G
authors.initials: DG
authors.lastname: Amaral
authors.forename: Larry R
authors.initials: LR
authors.lastname: Squire
mesh_terms: D000369:Aged, 80 and over; D000648:Amnesia, Retrograde / Q000473:pathology / Q000503:physiopathology / Q000523:psychology; D006801:Humans; D007859:Learning Disabilities / Q000473:pathology / Q000503:physiopathology / Q000523:psychology; D008297:Male; D013702:Temporal Lobe / Q000473:pathology* / Q000503:physiopathology*