期刊
NEUROBIOLOGY OF AGING
卷 32, 期 10, 页码 1849-1856出版社
ELSEVIER SCIENCE INC
DOI: 10.1016/j.neurobiolaging.2009.10.018
关键词
Aging; Dopamine; D-1 receptors; fMRI; Load-dependent BOLD response; Multimodal brain imaging; PET; Spatial working memory
资金
- Swedish Research Council
- Swedish Brain Power
- Alexander von Humboldt Research Award
- Joint Committee for Nordic Research Council in the Humanities
- Joint Committee for Nordic Research Council in the Social Science
In an fMRI study, 20 younger and 20 healthy older adults were scanned while performing a spatial working-memory task under two levels of load. On a separate occasion, the same subjects underwent PET measurements using the radioligand [C-11] SCH23390 to determine dopamine D-1 receptor binding potential (BP) in caudate nucleus and dorsolateral prefrontal cortex (DLPFC). The fMRI study revealed a significant load modulation of brain activity (higher load > lower load) in frontal and parietal regions for younger, but not older, adults. The PET measurements showed marked age-related reductions of D-1 BP in caudate and DLPFC. Statistical control of caudate and DLPFC D-1 binding eliminated the age-related reduction in load-dependent BOLD signal in left frontal cortex, and attenuated greatly the reduction in right frontal and left parietal cortex. These findings suggest that age-related alterations in dopaminergic neurotransmission may contribute to underrecruitment of task-relevant brain regions during working-memory performance in old age. (C) 2009 Elsevier Inc. All rights reserved.
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