Summary
Sleep deprivation consistently decreases vigilant attention, which can lead to difficulty in performing a variety of cognitive tasks. However, sleepâdeprived individuals may be able to compensate for degraded vigilant attention by means of topâdown attentional control. We employed a novel task to measure the degree to which individuals overcome impairments in vigilant attention by using topâdown attentional control, the Flexible Attentional Control Task (FACT). The FACT is a twoâchoice task that has trials with valid, invalid, and neutral cues, along with an unexpected switch in the probability of cue validity about halfway in the task. The task provides indices that isolate performance components reflecting vigilant attention and topâdown attentional control. Twelve healthy young adults completed an inâlaboratory study. After a baseline day, the subjects underwent 39âhours of total sleep deprivation (TSD), followed by a recovery day. The FACT was administered at 03:00, 11:00, and 19:00 during sleep deprivation (TSD condition) and at 11:00 and 19:00 after baseline sleep and at 11:00 after recovery sleep (rested condition). When rested, the subjects demonstrated both facilitation and interference effects on cued trials. While sleep deprived, the subjects showed vigilant attention deficits on neutral cue trials, and an impaired ability to reduce these deficits by using predictive contextual cues. Our results indicate that the FACT can dissociate vigilant attention from topâdown attentional control. Furthermore, they show that during sleep deprivation, contextual cues help individuals to compensate partially for impairments in vigilant attention, but the effectiveness of topâdown attentional control is diminished.