Patterns of regional brain hypometabolism associated with knowledge of semantic features and categories in Alzheimer's disease.

Full Abstract

The study of semantic memory in patients with Alzheimer's disease (AD) has raised important questions about the representation of conceptual knowledge in the human brain. It is still unknown whether semantic memory impairments are caused by localized damage to specialized regions or by diffuse damage to distributed representations within nonspecialized brain areas. To our knowledge, there have been no direct correlations of neuroimaging of in vivo brain function in AD with performance on tasks differentially addressing visual and functional knowledge of living and nonliving concepts. We used a semantic verification task and resting 18-fluorodeoxyglucose positron emission tomography in a group of mild to moderate AD patients to investigate this issue. The four task conditions required semantic knowledge of (1) visual, (2) functional properties of living objects, and (3) visual or (4) functional properties of nonliving objects. Visual property verification of living objects was significantly correlated with left posterior fusiform gyrus metabolism (Brodmann's area [BA] 37/19). Effects of visual and functional property verification for non-living objects largely overlapped in the left anterior temporal (BA 38/20) and bilateral premotor areas (BA 6), with the visual condition extending more into left lateral precentral areas. There were no associations with functional property verification for living concepts. Our results provide strong support for anatomically separable representations of living and nonliving concepts, as well as visual feature knowledge of living objects, and against distributed accounts of semantic memory that view visual and functional features of living and nonliving objects as distributed across a common set of brain areas.

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Author information

Author/s: Zahn, Roland (R); Garrard, Peter (P); Talazko, Jochen (J); Gondan, Matthias (M); Bubrowski, Philine (P); Juengling, Freimut (F); Slawik, Helen (H); Dykierek, Petra (P); Koester, Bernd (B); Hull, Michael (M);

Affiliation: Albert-Ludwigs-University Freiburg. zahnr(-atsign-)ninds.nih.gov

Journal and publication information

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

Journal: Journal of cognitive neuroscience (J Cogn Neurosci), published in United States. (Language: eng)

Reference: 2006-Dec; vol 18 (issue 12) : pp 2138-51

Dates: Created 2006/11/28; Completed 2007/02/08;

PMID: 17129196, status: MEDLINE (last retrieval date: 12/26/2008)

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

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Aged
Alzheimer Disease - metabolism; pathology; radionuclide imaging
Brain - radionuclide imaging
Brain Chemistry - physiology
Brain Mapping
Data Interpretation, Statistical
Female
Fluorodeoxyglucose F18 - diagnostic use
Humans

Knowledge
Male
Memory - physiology
Neuropsychological Tests
Positron-Emission Tomography
Psycholinguistics
Radiopharmaceuticals - diagnostic use
Regression Analysis
Semantics

Associated Chemicals: Radiopharmaceuticals (0) ; Fluorodeoxyglucose F18 (63503-12-8)

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