Daydreams incorporate recent waking life concerns but do not show delayed ('dream-lag') incorporations.

This study investigates the time course of incorporation of waking life experiences into daydreams. Thirty-one participants kept a diary for 10 days, reporting major daily activities (MDAs), personally significant events (PSEs) and major concerns (MCs). They were then cued for daydream, Rapid Eye Movement (REM) and N2 dream reports in the sleep laboratory. There was a higher incorporation into daydreams of MCs from the previous two days (day-residue effect), but no day-residue effect for MDAs or PSEs, supporting a function for daydreams of processing current concerns. A day-residue effect for PSEs and the delayed incorporation of PSEs from 5 to 7 days before the dream (the dream-lag effect) have previously been found for REM dreams. Delayed incorporation was not found in this study for daydreams. Daydreams might thus differ in function from REM sleep dreams. However, the REM dream-lag effect was not replicated here, possibly due to design differences from previous studies.

Consolidation of vocabulary is associated with sleep in typically developing children, but not in children with dyslexia.

Sleep is known to play an active role in consolidating new vocabulary in adults; however, the mechanisms by which sleep promotes vocabulary consolidation in childhood are less well understood. Furthermore, there has been no investigation into whether previously reported differences in sleep architecture might account for variability in vocabulary consolidation in children with dyslexia. Twenty-three children with dyslexia and 29 age-matched typically developing peers were exposed to 16 novel spoken words. Typically developing children showed overnight improvements in novel word recall; the size of the improvement correlated positively with slow wave activity, similar to previous findings with adults. Children with dyslexia showed poorer recall of the novel words overall, but nevertheless showed overnight improvements similar to age-matched peers. However, comparisons with younger children matched on initial levels of novel word recall pointed to reduced consolidation in dyslexics after 1 week. Crucially, there were no significant correlations between overnight consolidation and sleep parameters in the dyslexic group. This suggests a reduced role of sleep in vocabulary consolidation in dyslexia, possibly as a consequence of lower levels of learning prior to sleep, and highlights how models of sleep-associated memory consolidation can be usefully informed by data from typical and atypical development.