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

TY - JOUR

T1 - Patterns of regional brain hypometabolism associated with knowledge of semantic features and categories in alzheimer's disease

AU - Zahn, R.

AU - Garrard, P.

AU - Talazko, J.

AU - Gondan, Matthias

AU - Bubrowski, P.

AU - Juengling, F.

AU - Slawik, H.

AU - Dykierek, P.

AU - Koester, B.

AU - Hull, M.

PY - 2006/12

Y1 - 2006/12

N2 - 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.

AB - 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.

KW - Aged

KW - Alzheimer Disease

KW - Brain

KW - Brain Chemistry

KW - Brain Mapping

KW - Data Interpretation, Statistical

KW - Female

KW - Fluorodeoxyglucose F18

KW - Humans

KW - Knowledge

KW - Male

KW - Memory

KW - Neuropsychological Tests

KW - Positron-Emission Tomography

KW - Psycholinguistics

KW - Radiopharmaceuticals

KW - Regression Analysis

KW - Semantics

UR - http://www.scopus.com/inward/record.url?scp=33845473472&partnerID=8YFLogxK

U2 - 10.1162/jocn.2006.18.12.2138

DO - 10.1162/jocn.2006.18.12.2138

M3 - Journal article

C2 - 17129196

SN - 0898-929X

VL - 18

SP - 2138

EP - 2151

JO - Journal of Cognitive Neuroscience

JF - Journal of Cognitive Neuroscience

IS - 12

ER -