PT - JOURNAL ARTICLE AU - Valdas Noreika AU - Marc R. Kamke AU - Andres Canales-Johnson AU - Srivas Chennu AU - Jason B. Mattingley AU - Tristan A. Bekinschtein TI - Neurobehavioral dynamics of drowsiness AID - 10.1101/155754 DP - 2017 Jan 01 TA - bioRxiv PG - 155754 4099 - http://biorxiv.org/content/early/2017/06/26/155754.short 4100 - http://biorxiv.org/content/early/2017/06/26/155754.full AB - 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.