Neurobehavioral dynamics of drowsiness

Drowsiness varies continuously during daily activities, influencing both efficiency of daily behavior and sleep initiation. Yet, brain and behavioral dynamics underlying wake-sleep transitions, leading to the loss of perceptual awareness, are largely unknown in humans. Across levels of drowsiness we measured muscle and brain responses as participants attempted to detect their own hand movements elicited by transcranial magnetic stimulation to the motor cortex. Sleep and loss of consciousness processes –motor reorganization and decreased information shared by the brain– emerged through early drowsy states while participants were still conscious and able to take decisions. These findings demonstrate flexible adaption of perceptual processes to the changing neural dynamics of sleep onset long before the loss of responsiveness, and provide a mechanistic explanation for sleepiness affecting daily performance. . CC-BY-NC-ND 4.0 International license not peer-reviewed) is the author/funder. It is made available under a The copyright holder for this preprint (which was . http://dx.doi.org/10.1101/155754 doi: bioRxiv preprint first posted online Jun. 26, 2017;