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Sleepers Selectively Suppress Informative Inputs during Rapid Eye Movements
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International audience. Sleep leads to a disconnection from the external world. Even when sleepers regain consciousness duringrapid eye movement (REM) sleep, little, if any, external information is incorporated into dream content [1–3]. While gating mechanisms might be at play to avoid interference on dreaming activity [4], a total discon-nection from an ever-changing environment may prevent the sleeper from promptly responding to informa-tive events (e.g., threat signals). In fact, a whole range of neural responses to external events turns out to bepreserved during REM sleep [5–9]. Thus, it remains unclear whether external inputs are either processed or,conversely, gated during REM sleep. One way to resolve this issue is to consider the specific impact of eyemovements (EMs) characterizing REM sleep. EMs are a reliable predictor of reporting a dream upon awak-ening [10, 11], and their absence is associated with a lower arousal threshold to external stimuli [12]. Wethus hypothesized that the presence of EMs would selectively prevent the processing of informative stimuli,whereas periods of REM sleep devoid of EMs would be associated with the monitoring of external signals. Byreconstructing speech in a multi-talker environment from electrophysiological responses, we show that infor-mative speech is amplified over meaningless speech during REM sleep. Yet, at the precise timing of EMs,informative speech is, on the contrary, selectively suppressed. These results demonstrate the flexible ampli-fication and suppression of sensory information during REM sleep and reveal the impact of EMs on the se-lective gating of informative stimuli during sleep.