Preservation of categorical knowledge in Alzheimer's disease: a computational account.

Full Abstract

The distinction between knowledge of specific exemplars and knowledge of their general categories is central to much theorising on the nature of semantic memory. The dissociation between exemplar and category knowledge observed in Alzheimer's Disease (AD) would appear to support this distinction, and to suggest that different neural systems are involved in the representation of exemplar and category knowledge. We review the evidence for preserved category knowledge in the semantic memory impairment of AD, and propose an alternative interpretation, according to which category and exemplar knowledge are both represented in the same distributed neural substrate. The relative preservation of category knowledge is a consequence of the greater frequency, and hence greater robustness, of the representation of attributes shared by all or most members of a category, compared to exemplar-unique attributes. We test and confirm the computational adequacy of this hypothesis in two computer simulations.

Author information

Author/s: Tippett, L J (LJ); McAuliffe, S (S); Farah, M J (MJ);

Affiliation: University of Pennsylvania, USA.

Grants: R01 MH48274 (Agency:NIMH NIH HHS) ; R01 NS34030 (Agency:NINDS NIH HHS)

Journal and publication information

Publication Type: Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S.

Journal: Memory (Hove, England) (Memory), published in ENGLAND. (Language: eng)

Reference: -1995 Sep-Dec; vol 3 (issue 3-4) : pp 519-33

Dates: Created 1996/03/12; Completed 1996/03/12; Revised 2007/11/14;

PMID: 8574876, status: MEDLINE (last retrieval date: 2/18/2009, IMS Date: )

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

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