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On the relationship between knowledge and memory for pictures: Evidence from the study of patients with semantic dementia and Alzheimer's disease

Published online by Cambridge University Press:  01 November 1997

KIM S. GRAHAM
Affiliation:
University Neurology Unit, Addenbrooke's Hospital, Cambridge, CB2 2QQ, U.K. MRC Applied Psychology Unit, 15 Chaucer Road, Cambridge, CB2 2EF, U.K.
JAMES T. BECKER
Affiliation:
Neuropsychology Research Program, Departments of Psychiatry and Neurology, University of Pittsburgh Medical Center, Pittsburgh, PA 15213
JOHN R. HODGES
Affiliation:
University Neurology Unit, Addenbrooke's Hospital, Cambridge, CB2 2QQ, U.K. MRC Applied Psychology Unit, 15 Chaucer Road, Cambridge, CB2 2EF, U.K.

Abstract

Current views of long-term memory presume that both the hippocampal complex and the neocortex play interactive, but separate, roles in the storage of memories. While the neocortex is considered the eventual and permanent store for our memories, the encoding of recently experienced events is thought to be initially dependent upon the hippocampus and closely related structures. Neuropsychological studies have demonstrated that damage to the medial temporal lobe results in a retrograde amnesia extending back in time, with better preservation of older memories. The converse pattern has been shown in patients with semantic dementia, who have focal atrophy of the inferolateral temporal neocortex, but relative sparing of the hippocampal complex (Graham & Hodges, 1997). Here we demonstrate that such patients can show relatively preserved new learning on a forced-choice recognition memory test (based on real and chimeric animals), while patients in the early amnestic phase of Alzheimer's disease show severely impaired learning on the same test. This result provides support for the view that new learning is primarily dependent upon the hippocampus and related structures. (JINS, 1997, 3, 534–544.)

Type
Research Article
Copyright
© 1997 The International Neuropsychological Society

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