Changes in the environment require rapid modification or inhibition of ongoing behavior. We used the Stop-Signal paradigm and intracranial recordings to investigate response preparation, inhibition and monitoring of task relevant information. Electrocorticographic data (ECoG) was recorded in eight patients with electrodes covering frontal, temporal and parietal cortex, and time-frequency analysis was used to examine power differences in the beta (13-30 Hz) and high-gamma bands (60-180 Hz). Over motor cortex, beta power decreased and high-gamma power increased during motor preparation for both Go trials and unsuccessful stops. For successful stops, beta increased and high-gamma was reduced, indexing the cancellation of the prepared response. In the middle frontal gyrus (MFG), stop-signals elicited a transient high-gamma increase. The MFG response occurred before the estimated stop signal reaction time, but did not distinguish between successful and unsuccessful stop-trials, likely signaling attention to the salient stop-stimulus. A post-response high-gamma increase in MFG was stronger for unsuccessful compared to successful stops and absent in go-trials, supporting a role in behavior monitoring. These results provide evidence for differential contributions of frontal sub-regions to response inhibition including motor preparation and inhibitory control in motor cortex, and cognitive control and action evaluation in lateral prefrontal cortex.
- beta oscillations
- motor control
- stop-signal task
- Copyright © 2015, Journal of Neurophysiology