Age-related differences in activation-performance relations in delayed-response tasks: A multiple component analysis

Bart Rypma, Dana A. Eldreth, Donovan Rebbechi

Research output: Contribution to journalArticlepeer-review

59 Scopus citations

Abstract

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.

Original languageEnglish (US)
Pages (from-to)65-76
Number of pages12
JournalCortex
Volume43
Issue number1
DOIs
StatePublished - Jan 2007

Keywords

  • Aging
  • Individual differences
  • Prefrontal cortex
  • Working memory
  • fMRI

ASJC Scopus subject areas

  • Neuropsychology and Physiological Psychology
  • Experimental and Cognitive Psychology
  • Cognitive Neuroscience

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