Neural Correlates of Proactive and Reactive Control

This ERP study investigated central nervous correlates of proactive and reactive control using a novel precued antisaccade paradigm. Proactive control refers to preparatory processes during anticipation of a behaviorally relevant event; reactive control is activated after such an event to ensure goal attainment. A 64-channel EEG was obtained in 35 healthy subjects; video-based eye tracking was applied for ocular recording. In the task, a target (probe) appeared left or right of the fixation point 1800ms after a visual cue; subjects had to move their gaze to the probe (prosaccade) or its mirror image position (antisaccade). Probes were emotional face expressions, with their frame colors instructing task requirements. The cue informed about antisaccade probability (70% vs. 30%) in each trial. High antisaccade probability was associated with larger CNV amplitude than low antisaccade probability. In trials with incongruence between expected and actual task requirements, probe N2 and P3a amplitudes were larger than in congruent trials. P3a was smaller for affective than neutral probes, irrespective of congruency. Task accuracy and speed were lower in incongruent trials and varied according to affective probe valence. EEG source imaging suggested the origin of the ERPs to be in orbitofrontal cortex and superior frontal gyrus. The effect on the CNV indicates greater cortical activity during higher proactive control demands. Larger probe N2 and P3a in incongruent trials reflect greater resource allocation to conflict monitoring and conflict resolution, i.e., reactive control. The influence of probe valence on P3a suggests reduction of processing capacity due to higher emotional arousal.