1. Abstract
Sleep loss has detrimental effects on cognitive and emotional functioning. These impairments have been associated with alterations in EEG measures of power spectrum and event-related potentials, however the impact of sleep loss on inter trial phase coherence (ITPC), a measure of phase consistency over experimental trials, remains mostly unknown. ITPC is thought to reflect the ability of the neural response to temporally synchronize with relevant events, thus optimizing information processing.
In the current study we investigated the effects of sleep deprivation (SD) on information processing by evaluating the phase consistency of steady-state visual evoked potentials (ssVEPs) obtained from a group of 18 healthy individuals following 24 hours of total SD and after a night of habitual sleep. An ssVEP task was utilized, which included the presentation of dots flickering at 7.5 Hz, along with a cognitive-emotional task. Our results show that ITPC is significantly reduced under SD relative to habitual sleep. Interestingly, the decrease in ITPC was accompanied by a decrease in behavioral performance in the ssVEP cognitive-emotional task, and the psychomotor vigilance task (PVT) in the majority of our participants.
The results suggest that the capability of the brain to synchronize with rhythmic stimuli is disrupted in SD. Thus, decreased ITPC may represent an objective and mechanistic measure of SD, allowing future work to study the relation between brain-world synchrony and the specific functional impairments associated with SD.