A 45-Minute Power Nap Can Boost Your Memory Five-Fold
Title: Nap sleep preserves associative but not item memory performance
Journal: Neurobiology of Learning and Memory
Author: Studte et al
Objective: “To reveal the role of naps for hippocampus-dependent associative memory (AM) and hippocampus-independent item memory (IM) alongside their corresponding event-related potential old/new effects.”
Sleep is known to play a role in memory consolidation enabling recall of information in the future.
Conversely, a lack of sleep is shown to have detrimental effects on recall and retention.
How sleep enhances memory is not entirely understood, but is known to involve both the hippocampus and cortex. Different studies have found that different stages of sleep are involved in memory consolidation, including slow wave sleep and rapid eye movement.
What is also less well understood is the role of “napping” or brief periods of sleep on the function of memory consolidation (and, frankly, other cognitive functions). The authors of this study sought to investigate that.
Participants learned 90 single words and 120 unrelated word-pairs before performing an item memory and an associative memory test to establish a baseline.
One group was subsequently allowed to nap (90 min) while the other watched DVDs (control group).
Afterwards, both groups performed a final item memory and an associative memory test for the learned stimuli.
Item memory performance decreased for both groups,
Associative memory performance decreased for the control group but remained constant for the nap group.
A 90 minute nap improved associative memory performance more than 5 fold compared to participants who did not nap.
Positive correlations were observed between spindle density during slow-wave-sleep and non-REM sleep and associative memory baseline performance, showing that successful learning and retrieval both before and after sleep relates to spindle density during nap sleep.
Together, these results speak for a selective beneficial impact of naps on hippocampus-dependent memories.
Even a short sleep lasting 45 to 60 minutes appears to produce a five-fold improvement in information retrieval from memory
Thus, wherever people are in a learning environment, they should think seriously about the positive effects of sleep.