Is sleep-dependent memory consolidation of a visuo-motor task related to dream content?
A considerable amount of studies have shown that sleep facilitates memory consolidation. For procedural memory, some findings support the association with REM sleep but the relationship between memory consolidation and dreaming has been scarcely studied. The present study did not find an effect of direct incorporations of the mirror tracing task into the dream on over-night improvement. On the other hand, bizarre, long, and intense dreams were associated with poorer performance regarding speed but also with decreased amount of errors. Whether this can be explained by altered sleep physiology or negative effects of dreams on mood and performance can not yet been answered. Future research should study more complex and demanding procedural memory tasks and the relationship between dreaming and sleep-dependent consolidation of emotional memories.