Functional Coupling of Human Prefrontal and Premotor Areas during Cognitive Manipulation

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 ϫ 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.

Changes in brain activity in response to problem solving during the abstinence from online game play

“…In two studies, dysfunctional activity in the DLPFC during working memory tasks and improvement in activity performance due to short term abstinence have been reported in subjects with marijuana addiction (Pope, Gruber, Hudson, Huestis & Yurgelun-Todd, 2001;Yurgelun-Todd et al, 1998). In addition to the involvement of the prefrontal cortex, there is also evidence that highlights the relationship between activation of the DLPFC and the premotor cortex during working memory tasks (Abe et al, 2007;Wallis & Miller, 2003). A reciprocal link between the DLPFC and premotor areas was activated when subjects performed "delayed-encoding recognition task" (Abe et al, 2007).…”

“…In addition to the involvement of the prefrontal cortex, there is also evidence that highlights the relationship between activation of the DLPFC and the premotor cortex during working memory tasks (Abe et al, 2007;Wallis & Miller, 2003). A reciprocal link between the DLPFC and premotor areas was activated when subjects performed "delayed-encoding recognition task" (Abe et al, 2007). Using tasks that require prompt switching between two arbitrary rules, Wallis and Miller (2003) suggested the neural connection for interpreting rules and linking them with motor responses.…”

Errors and Conflict at the Task Level and the Response Level

“…Pollmann (2000) and Pollmann et al (2000) already associated left frontopolar cortex with changes in visual dimension. The RCZ is often reported as a response conflict region, whereas task conflict seems to be correlated with regions associated with more abstract cognitive processes such as the preSMA and the premotor cortex (Abe et al, 2007). This anterior-posterior dissociation is partly reproduced in our response-and task-conflictrelated brain regions.…”

Respiratory, postural and spatio-kinetic motor stabilization, internal models, top-down timed motor coordination and expanded cerebello-cerebral circuitry: a review

“…The prefrontal cortex, indeed seems to act both as a higher area for planning, sequencing, monitoring and selecting appropriate motor actions, and as an area for doing these computational operations for cognitive processes (Abe et al, 2007;Mushiake et al, 2006;Slachevsky et al, 2003). As noted above, internal models can underlie a diverse range of nonmotor-type cognitions.…”