Resting-state fMRI study of vigilance level under endogenous modulation based on ReHo and fALFF in humans under normal entrained conditions

Time-dependent neuromodulation mechanisms in human cognitive-behavioral tasks are not yet fully established. The present study aimed to analyze the changes in resting-state functional magnetic resonance imaging (rs-fMRI) blood oxygen level dependent (BOLD) signals over the 24-h day and their correlation with vigilance level. We recruited 20 healthy volunteers to be scanned at six-time points 24 hours a day. Compared to 9:00, 13:00, 17:00, and 21:00h, thalamic BOLD signals increased and vigilance level decreased at 1:00 and 5:00h. We speculate that the BOLD signals increased in the thalamus may represent a compensatory mechanism for maintaining relative vigilance level.