Neural correlates of the Simon effect modulated by practice with spatial mapping

The operation of cognitive control relies on existing stimulus-response (S-R) mapping rules in the brain. However, it remains unclear how a newly acquired S-R mapping rule (i.e., learning) may alter the cognitive control system. We examined this question with functional magnetic resonance imaging and the Simon effect influenced by preceding practice. Behavioral results revealed a reversed Simon effect following practice with incompatible spatial location mapping (experimental group; n=20) but a classic Simon effect in the group with compatible location mapping practice (control group; n=20). Neuroimaging results showed reduced activity in the anterior midcingulate cortex (aMCC) and increased functional coupling between the aMCC and the right frontopolar cortex (FPC) in the experimental group compared to the control group. The bilateral temporoparietal junction responded more to the stimuli that matched a task configuration related to prior practice. In addition, the functional circuit of the right FPC-ventral premotor cortex (vPMC) correlated with the Simon effect influenced by prior practice, suggesting that the FPC-vPMC pathway might represent the abstract response rule acquired during practice and applies the rule to modify behavior. Collectively, these findings reveal how the brain represents previously learned response rules and subsequently modifies the cognitive control system.