Stop and go: the neural basis of selective movement prevention.

Converging lines of evidence show that volitional movement prevention depends on the right prefrontal cortex (PFC), especially the right inferior frontal gyrus (IFG). Selective movement prevention refers to the rapid prevention of some, but not all, movement. It is unknown whether the IFG, or other prefrontal areas, are engaged when movement must be selectively prevented, and whether additional cortical areas are recruited. We used rapid event-related fMRI to investigate selective and nonselective movement prevention during performance of a temporally demanding anticipatory task. Most trials involved simultaneous index and middle finger extension. Randomly interspersed trials required the prevention of one, or both, finger movements. Regions of the right hemisphere, including the IFG, were active for selective and nonselective movement prevention, with an overlap in the inferior parietal cortex and the middle frontal gyrus. Selective movement prevention caused a significant delay in movement initiation of the other digit. These trials were associated with activation of the medial frontal cortex. The results provide support for a right-hemisphere network that temporarily "brakes" all movement preparation. When movement is selectively prevented, the supplementary motor cortex (SMA/pre-SMA) may participate in conflict resolution and subsequent reshaping of excitatory drive to the motor cortex.