The roles of prefrontal brain regions in components of working memory: Effects of memory load and individual differences

Bart Rypma, Mark D'Esposito

Research output: Contribution to journalArticle

420 Scopus citations

Abstract

Using an event-related functional MRI design, we explored the relative roles of dorsal and ventral prefrontal cortex (PFC) regions during specific components (Encoding, Delay, Response) of a working memory task under different memory-load conditions. In a group analysis, effects of increased memory load were observed only in dorsal PFC in the encoding period. Activity was lateralized to the right hemisphere in the high but not the low memory- load condition. Individual analyses revealed variability in activation patterns across subjects. Regression analyses indicated that one source of variability was subjects' memory retrieval rate. It was observed that dorsal PFC plays a differentially greater role in information retrieval for slower subjects, possibly because of inefficient retrieval processes or a reduced quality of mnemonic representations. This study supports the idea that dorsal and ventral PFC play different roles in component processes of working memory.

Original languageEnglish (US)
Pages (from-to)6558-6563
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume96
Issue number11
DOIs
StatePublished - May 25 1999

ASJC Scopus subject areas

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