HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Zahn, R. Articles by Hull, M. Search for Related Content PubMed Articles by Zahn, R. Articles by Hull, M.

Patterns of Regional Brain Hypometabolism Associated with Knowledge of Semantic Features and Categories in Alzheimer's Disease

¹ Albert-Ludwigs-University Freiburg, ² National Institute of Neurological Disorders and Stroke, National Institutes of Health, ³ University College London, ⁴ Royal Free Hospital, ⁵ University of Regensburg, ⁶ Inselspital and University of Bern

Reprint requests should be sent to Roland Zahn, Cognitive Neuroscience Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, 5C205, Building 10, MSC 1440, 10 Center Drive, Bethesda, MD 20892-1440, or via e-mail: zahnr{at}ninds.nih.gov.

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 nonliving 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.

This article has been cited by other articles:

				R. Zahn, J. Moll, F. Krueger, E. D. Huey, G. Garrido, and J. Grafman Social concepts are represented in the superior anterior temporal cortex PNAS, April 10, 2007; 104(15): 6430 - 6435. [Abstract] [Full Text] [PDF]