期刊
CORTEX
卷 43, 期 1, 页码 65-76出版社
ELSEVIER MASSON, CORP OFF
DOI: 10.1016/S0010-9452(08)70446-5
关键词
prefrontal cortex; working memory; aging; individual differences; fMRI
资金
- NIA NIH HHS [R01 AG029523] Funding Source: Medline
- NIMH NIH HHS [MH61636] Funding Source: Medline
- NATIONAL INSTITUTE OF MENTAL HEALTH [R03MH061636] Funding Source: NIH RePORTER
- NATIONAL INSTITUTE ON AGING [R01AG029523] Funding Source: NIH RePORTER
We used event-related functional magnetic resonance imaging (fMRI) to measure prefrontal cortex (PFC) activity while younger and older adults performed an item-recognition task in which the memory-set size varied between 1 and 8 letters. Each trial was composed of a 4-sec encoding period in which subjects viewed random letter strings, a 12-sec retention period and a 2-sec retrieval period in which subjects decided whether a single probe letter was or was not part of the memory set. For both groups, reaction-time (RT) increased and accuracy decreased with increasing memory set-size. Analyses of individual subjects' performance and cortical activity indicated that speed and accuracy accounted for variance in different task periods in dorsal and ventral PFC. Age-related differences in accuracy-activation relations were observed in dorsal PFC during encoding and ventral PFC during maintenance. Age-related differences in RT-activation relations were observed in dorsal PFC during retrieval. These results and additional fMRI data we have collected during performance of a speeded processing task, directly support a model of cognitive slowing in which processing rate is related to neural efficiency.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据