Task switching following 24 h of total sleep deprivation: a functional MRI study.

Task switching is a ubiquitous feature of many human activities that involve multitasking. In addition, owing to occupational demands, many individuals are required to engage in task switching under various levels of sleep deprivation, such as those who work in military and medical contexts. Nevertheless, little is known about the effects that sleep loss has on the neural bases of task switching. To address this shortcoming, we administered a cued switching task to participants following a night of normal sleep and also following a night of total sleep deprivation - in counterbalanced order. The behavioral results demonstrated a cost (i.e. longer reaction time) both as a function of sleep deprivation and task switching. Sleep deprivation resulted in greater activation in the frontoparietal network, whereas task switching was correlated with greater activation in the thalamus and superior temporal gyrus. However, despite increases in fatigue and sleepiness and a reduction in cognitive effectiveness (computed from actigraphic data), the reaction time cost associated with switching (i.e. switch cost) was not exacerbated by sleep deprivation. The results are discussed in terms of the involvement of executive functions in mitigating the effects of sleep deprivation on task switching.