Functional coupling of human prefrontal and premotor areas during cognitive manipulation.

Full Abstract

Evidence indicates the involvement of the rostral part of the dorsal premotor cortex (pre-PMd) in executive processes during working memory tasks. However, it remains unclear what the executive function of pre-PMd is in relation to that of the dorsolateral prefrontal cortex (DLPFC) and how these two areas interact. Using functional magnetic resonance imaging (fMRI), brain activity was examined during a delayed-encoding recognition task. Fifteen subjects had prelearned several four-code standard sequences and super sequences (SUPs) consisting of a train of two standard sequences to form "chunks" in long-term memory. During fMRI, subjects remembered eight-code encoding stimuli presented as an SUP or two unlinked standard sequences (2STs). A memory probe prompted the subjects to recognize codes across two chunks (ACROSS) or within a single chunk. A 2 x 2 factorial design was used to test two types of working memory manipulation:
(1) a reductive operation selecting codes from chunks ("segmenting") and (2) a synthetic operation converting unlinked codes into a sequence ("binding"). Response time data supported the behavioral effects of each operation. Event-related fMRI showed that the "segmenting operation" activated the DLPFC bilaterally, whereas the "binding operation" enhanced the left pre-PMd activity. Activity in the ventrolateral prefrontal cortex suggested its involvement in the retrieval of task-relevant information from long-term memory. Furthermore, effective connectivity analysis indicated that the left pre-PMd and ipsilateral DLPFC interacted specifically during the ACROSS recognition of 2STs, the condition that involved both operations. We propose specific neural substrates for working memory manipulation:
the DLPFC for segmenting/attentional selection and the pre-PMd for binding/sequencing. The functional coupling between the DLPFC and pre-PMd appears to play a role in combining these distinct operations.

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Author information

Author/s: Abe, Mitsunari (M); Hanakawa, Takashi (T); Takayama, Yoshihiro (Y); Kuroki, Chihiro (C); Ogawa, Seiji (S); Fukuyama, Hidenao (H);

Affiliation: Human Brain Research Center, Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan.

Journal and publication information

Publication Type: Clinical Trial; Journal Article; Research Support, Non-U.S. Gov't

Journal: The Journal of neuroscience : the official journal of the Society for Neuroscience (J Neurosci), published in United States. (Language: eng)

Reference: 2007-Mar; vol 27 (issue 13) : pp 3429-38

Dates: Created 2007/03/29; Completed 2007/04/24;

PMID: 17392459, status: MEDLINE (last retrieval date: 12/26/2008)

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Male
Memory - physiology
Motor Cortex - physiology
Parietal Lobe - physiology
Prefrontal Cortex - physiology
Reaction Time
Recognition (Psychology) - physiology

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