Modulation of Neural Compensatory Response by Duration of Sleep Deprivation in a Cognitive Flexibility Task.

The neural compensation mechanism involves maintaining cognitive performance during sleep deprivation (SD) by triggering alternative neural activations. While cognitive task complexity modulates post-SD neural activation, the role of SD duration remains uncertain. Thirty-three healthy college students (16 male and 17 female) completed a 36-h SD protocol, performing a switching task at baseline (pre-SD), after 24 h of SD (SD-24), and after 36 h of SD (SD-36). Resting-state EEG signals were recorded for 5 min at each SD stage and analysed using Standardised Low-Resolution Electromagnetic Tomography. Behavioural results showed that task performance declined after SD-24 compared to pre-SD, but recovered toward baseline levels after SD-36. Additionally, cognitive flexibility was lower after SD-24 and SD-36 than pre-SD, with no significant difference observed between SD-24 and SD-36. EEG results indicated decreased activation of the orbitofrontal and superior frontal gyrus after SD-24 and SD-36 compared to pre-SD, but increased activation of the superior parietal lobe after SD-36 compared to SD-24. The results of this study suggest that compensatory mechanisms depend on SD duration, indicating that effective neural compensation requires sustained wakefulness to activate fully.