Motor Sequence Learning Under Sleep Deprivation.

Sleep deprivation (SD) compromises declarative memory encoding and subsequent consolidation, yet its consequences for the acquisition of new motor skill learning remain unknown. Forty-eight healthy adults underwent either one night of total SD or normal sleep and were tested the next morning using a multimodal approach combining psychomotor vigilance, subjective sleepiness, cortisol, brain-derived neurotrophic factor (BDNF), and corticospinal excitability, alongside a standardised explicit motor sequence learning task dissociating goal-based accuracy from movement-based execution speed. SD induced a marked psychophysiological stress state-elevated cortisol, reduced vigilance, and increased sleepiness-without altering BDNF levels or brain excitability. Motor learning elicited the expected intracortical disinhibition across groups, yet SD did not modulate BDNF or corticospinal excitability following skill acquisition. The main findings showed that SD selectively reduced movement time gains during acquisition while sparing spatial accuracy, revealing a dissociation between motor execution efficiency and goal representation. Importantly, this selective alteration did not persist beyond training, as delayed consolidation (24 Hours and 7 Days) remained preserved. Together, these findings provide the first direct evidence of a component-specific vulnerability of sequential motor learning to a full night of SD in the absence of detectable alterations in plasticity-related markers.