Event-related brain potentials and cognitive flexibility

Introduction: Adaptive flexibility of behaviour is closely related to the supervisory control of selective attention. The neuropsychological assessment of cognitive flexibility is focussed on the analysis of perseverations in card-matching tasks such as the Wisconsin Card Sorting Test (WCST). Method: Variants of a card-matching task were established in which events that signalled the need to shift attention were presented before (prospective cuing) or after (retrospective cuing) the selection of responses. Eighteen healthy volunteers participated. Event-related brain potentials (ERPs) were collected from these individuals during their performance of the card-matching tasks. Results: Selective activity from particular brain regions (i. e., the P3a component of the ERP) was specifically associated with retrospectively, but not with prospectively, demanded shifts of attention. Discussion: The P3a in card-matching tasks provides a neural correlate of supervisory attentional control that selects and maintains task-relevant representations thus imposing attentional sets for adaptive flexibility in behaviour. Conclusion: The implications of this finding are twofold: It constitutes evidence favouring the actual existence of executive attentional shifts, and it characterises their neural implementation, the prefrontal region of the cerebral cortex. Implications for experimental techniques are discussed which may be designed in the future to challenge cognitive flexibility.