Abstract: Sleep leads to a disconnection that allows optimizing neural plasticity but renders organisms vulnerable to external threats. Yet, despite the absence of behaviors, the sleeping brain remains responsive to sensory inputs. Here, we provide evidence that humans enter a standby mode during which they continue tracking their environment for relevant signals. First, using EEG markers of motor preparation, we show that the human brain, even after falling asleep, continues to classify auditory events in a task-dependent manner. Second, through EEG markers of attention selection, we show that sleepers can resolve the cocktail party phenomenon, by selectively attending towards relevant messages over irrelevant ones. Third, through EEG markers of perceptual learning for acoustic noise, we provide evidence that memory traces can be both formed or suppressed during sleep, depending on sleep phase. Finally, we provide evidence that the sleeping brain continued connection with the external world is restricted to specific sleep stages, and that the presence or absence of neural responsiveness can be traced back to characteristic sleep physiology. These findings provide new insights about the mechanisms of sensory disconnection and neural plasticity in sleep.
In the media: Sid’s recent article in Nature Communications, on how our brains can learn but also unlearn during sleep, has been covered in various international media this week, e.g.:
The Washington Post: Your brain can form new memories while you are asleep, neuroscientists show
Politiken: Hjernen kan lytte og lære, mens du sover