Proceedings of the Annual Meeting of the Cognitive Science Society

The cognitive control of action is thought to be mediated byconscious effort as reflected by changes in frontal theta activity. Wemeasured frontal theta during a response inhibition task in 16healthy adults who implicitly learned repeated patterns of go/switchcues, resulting in unaware differences in cognitive demand fordifferent cues. Learning was reflected by reduced reaction times(RT) to probable compared to unexpected switch cues. In the rareabsence of behavioural (RT) differences, concurrent measures ofpupil diameter revealed changes in effort with stimulus probability,while effort was accompanied by parametric increases intheta. Additionally, theta predicted pre-response sensorimotorgamma, suggesting interactions between frontal and sensorimotorcortex during cognitive control. These results provide furtherevidence for a functional role of theta in cognitive effort duringresponse preparation, inhibition and execution, even in the absenceof conscious awareness.