Induced cortical gamma-band oscillations reflect cognitive control elicited by implicit probability cues in the preparing-to-overcome-prepotency (POP) task

Previous research suggests that synchronous cortical gamma-band oscillations reflect the implementation of cognitive control in anticipation of the need to overcome prepotent responses. These studies often require participants to link task instructions with task cues signaling the need (or lack thereof) for cognitive control. Thus, the oscillatory response elicited by these cues may also reflect the implementation of explicit task instructions. The aim of this research was to determine whether gamma-band oscillations would also be increased in preparation for cognitive control when the need for that control was only made implicitly available to the participant. Using a task-ambiguous cue to indicate the position of a subsequent probe stimulus, we manipulated the need for cognitive control by varying the probability of high- and low-control probes appearing in each of two positions. Results show that participants developed the anticipated expectancies regarding probe identity in the two positions and that the anticipation of a high-control probe was associated with an increase in the power of induced cortical gamma band over frontal scalp recording sites.