Task reconfiguration and carryover in task switching: an event-related potential study.

This study investigated the electrophysiological correlates of the processes involved in task switching. A pair-wise task-switching paradigm was used where each trial comprised two tasks that were either the same (task repeat) or different (task switch). In the paradigm, task-switch and repeat trials are compared in conditions of foreknowledge and non-foreknowledge of the forthcoming task type and during different response-stimulus intervals (RSIs). The results of this study show that, before the second task began in a task-pair trial, i.e., during the RSI, there was a CNV-like negativity for all trials. This indicates a general anticipatory effect. In foreknowledge conditions, there is an additional switch-specific reconfiguration process followed by a task-specific (including both switch- and repeat-related) preparatory process. During the post-task 2 stage, P3b was found to be smaller in switch trials than in repeat trials. Such differential P3b between switch and repeat trials appeared earlier and larger in foreknowledge than in non-foreknowledge conditions. The results of this study support the existence of advance preparation and uphold the role of carryover effects in task switching.