Oscillatory dynamics of sustained attention states

Sustained attention enables individuals to concentrate on a task over an extended period of time. This ability is known to fluctuate, resulting in periods of effective task focus ('in the zone') and periods of increased performance variability and susceptibility to errors ('out of the zone'). Little is known about the oscillatory neural dynamics that underlie each of these states and their transitions during sustained attention tasks. To address this, we had thirty young adults perform the gradual onset continuous performance task (gradCPT), during which their EEG and behavioural responses were recorded. States of sustained attention (in vs. out of the zone) throughout the task were identified based on the variance time course of participants' reaction times. Out of the zone states were associated with increased errors of commission and reduced perceptual sensitivity compared to in the zone states, as expected. Importantly, a significant decline in theta oscillations at mid-prefrontal regions was found in out of the zone (vs. in the zone) states over a ~400 ms period around the transition point between stimuli, and the extent of this decline predicted commission errors, RT variability, and response bias. In addition, individual differences in the variability of frontal theta rhythm were associated with RT variability. Finally, participants exhibiting greater theta variability showed a more pronounced decline in perceptual sensitivity when out of the zone and less stable RTs compared to those with lower variability. Our results suggest that states of diminished sustained attention, even during short lapses, are characterized by a reduction in frontal theta activity, and that fluctuations in this rhythm covary with fluctuations in attentional control.