Voluntary action control requires selection of appropriate responses and stopping of inappropriate responses. Selection and stopping are often investigated separately, but they appear to recruit similar brain regions, including the pre-supplementary motor area (preSMA) and inferior frontal gyrus. We therefore examined the evidence for overlap of selection and stopping using two approaches: a meta-analysis of existing studies of selection and stopping, and a novel within-subject fMRI study in which action selection and a stop signal task were combined factorially. The novel fMRI study also permitted us to investigate hypotheses regarding a common mechanism for selection and stopping. The preSMA was identified by both methods as common to selection and stopping. However, stopping a selected action did not recruit preSMA more than stopping a specified action, nor did stop signal reaction times differ significantly across the two conditions. These findings suggest that the preSMA supports both action selection and stopping, but the two processes may not require access to a common inhibition mechanism. Instead, the preSMA might represent information about potential actions that is used in both action selection and stopping in order to resolve conflict between competing available responses.
Keywords: Action selection; Action stopping; FDRc; Inferior frontal gyrus; Inhibition; Pre-supplementary motor area; RT; SSRT; Stop signal task; fMRI; false discovery rate cluster corrected; functional magnetic resonance imaging; pre-supplementary motor area; preSMA; reaction time; stop signal reaction time.
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