Fig. 1.

Noise memory paradigm in wakefulness and sleep. a, b Stimuli and expected results: Participants (N = 20) were instructed to discriminate between trials made of running white noise (N) and trials that contained a repeated pattern (RN and RefRN), made by the seamless concatenation of short (0.2 s) noise segments (targets) interleaved with 0.3 s fresh white-noise fillers. RN (within-trial repetition) and RefRN (within- and across-trial repetition) trials had an identical structure and differed only regarding the amount of exposure to the target. Participants’ ability to discriminate RN from N trials evidences shorter-term memory for the novel repeated target. A better discrimination for RefRN compared to RN trials additionally indicates longer-term memory processes (a, right). c Full-night recording:. Each recording session started with a pre-sleep phase, during which participants were instructed to remain awake. In all, 5 unique randomly generated RefRN were used in the pre-sleep phase for each participant. In the sleep phase, participants were lying on a bed while being continuously exposed to white-noise stimuli. Different sets of unique RefRN targets were used depending on participants’ vigilance states (wake, non-rapid eye movement (NREM) and REM sleep). Finally, participants were tested upon awakening (post sleep) on all RefRN targets heard during the pre-sleep and sleep phases, along with 5 novel RefRNs (memory test). Each RefRN target was played in a separate block along new RN and N trials