Nap‐dependent learning in infants

Abstract

Sleep has been shown to aid a variety of learning and memory processes in adults (Stickgold, 2005). Recently, we showed that infants' learning also benefits from subsequent sleep such that infants who nap are able to abstract the general grammatical pattern of a briefly presented artificial language (Gomez, Bootzin & Nadel, 2006). In the present study, we demonstrate, for the first time, long-term effects of sleep on memory for an artificial language. Fifteen-month-old infants who had napped within 4 hours of language exposure remembered the general grammatical pattern of the language 24 hours later. In contrast, infants who had not napped shortly after being familiarized with the language showed no evidence of remembering anything about the language. Our findings support the view that infants' frequent napping plays an essential role in establishing long-term memory.

Overlapping memory replay during sleep builds cognitive schemata

“…It also builds upon prior suggestions that SWS-based transfer of information might combine with synaptic downscaling to erase memories in which connections have not been sufficiently strengthened by replay [12,30,44]. In sum, although there is ample evidence that abstraction can occur during wake, this process is facilitated by sleep [1][2][3][4][5]. We argue that the unique combination of veridical replay, synaptic downscaling, comparative sensory isolation and favourable neuropharmacology that occurs during SWS could underpin this facilitation.…”

“…It explains why newly learned material becomes increasingly easy to integrate and remember as a conceptual schema takes shape [18,19]. It also explains the observed postsleep enhancements in integration [6][7][8], abstraction [1][2][3][4][5], insight [9] and false memory formation [28].…”

“…The temporal synchronisation of thalamocortical spindles and sharp waves by slow oscillations is believed to ensure that sequence replay in the hippocampus coincides with neocortical readiness for encoding, and thereby facilitates the transfer of sequences from the hippocampus to the neocortex [14,43]. This provides a potential physiological mechanism for offline consolidation of hippocampalbased memories during sleep [2,61,62] (for reviews [14,43]). …”

“…In considering this issue we should note that the behavioural studies of integration [6][7][8], abstraction [1][2][3][4][5], insight [9] and false memory formation [28] discussed above all suggest that sleep facilitates the formation of connections between related items. Importantly, performance on these tasks typically improves across both wakefulness and sleep but improvement is greater across the latter.…”

“…Central shared concepts of this type can be thought of as the 'gist' (see Glossary), or essential features, of a set of memories, and taken together can form a cognitive framework of expectations or schema (Box 1). This article proposes a physiological mechanism by which memory replay during sleep could be responsible for the abstraction of gist information from newly encoded memories to form cognitive schemata.Recent research has shown that sleep facilitates abstraction of gist information [1][2][3][4][5] as well as integration across multiple memories [6][7][8], insight into hidden solutions [9], and even the ability to make creative connections between distantly related ideas and concepts [10]. These findings build upon a strong body of work demonstrating that sleep plays a crucial role in memory consolidation (for reviews [11][12][13]), as well as a highly influential model of how memories are re-organised and strengthened by replay during slow wave sleep (SWS) (see [11,12,[14][15][16][17] and Box 2).…”