Humans can unconsciously acquire new information during deep sleep. Although sleep-played information can guide behavior during subsequent wakefulness, sleep-formed memories cannot be remembered consciously after awakening. We explored whether sleep-learning might expedite conscious learning during subsequent wakefulness by providing a first bout of carving a new memory trace, which ensuing wake-learning can build on. We analyzed previously unreported data acquired in a recent study on vocabulary learning during slow-wave sleep (Zust et al., 2019, Curr Biol). Sleep-played vocabulary was successfully retrieved in an implicit memory test administered following awakening. However, sleep-learning diminished instead of increased wake relearning of the same vocabulary. We speculate that vocabulary learning during sleep may have interfered with the synaptic down-scaling of hippocampal and neocortical language-related neurons, which were then too saturated for further potentiation required for the wake-relearning of the same vocabulary.
bioRxiv Subject Collection: Neuroscience