Research press release


Nature Communications

Neuroscience: How you can learn in your sleep


睡眠中の学習が可能かどうかを調べる研究は、これまでも行われてきているが、睡眠中の学習が可能なことを実証したものと睡眠中の新規記憶形成の証拠を示せなかったものがあり、結論の一致が見られない。今回、Thomas Andrillonたちの研究チームは、この結論の不一致が、脳活動の種類が睡眠相によって異なるという事実によるものと考え、そのために被験者が学習できる場合とできない場合が生じる可能性があるという仮説を提起した。Andrillonたちは、この仮説を検証するため、睡眠中の被験者の脳活動を測定し、被験者にさまざまな音系列を聞かせた。そして被験者が目を覚ました後、睡眠中に聞いた音をどの程度はっきりと認知できるのかを検査した。REM睡眠時に音系列を聞いた被験者は、この検査の成績が良好だったが、NREM睡眠時に音を聞いた被験者は、成績が悪かった。また、Andrillonたちは、夜間における被験者の音に対する応答を解析し、REM睡眠時における学習効果を確認した。一方、NREM睡眠時については、浅い眠りと深い眠りで明確な違いのあることが観察され、眠りが浅いと睡眠中の学習は可能だったが、眠りが深いと学習は抑制された。


The formation of new memories is only possible during certain phases of sleep, shows a study published this week in Nature Communications. Rapid eye-movement (REM) or light, non-REM (NREM) sleep is found to be conducive to learning, whereas deep NREM sleep had a suppressive effect on the ability to learn new information. The findings may help us to understand more about the function of distinctive phases of sleep.

Previous research investigating whether or not we can learn during sleep has produced mixed results, with some studies showing that people can learn while asleep, and others failing to provide evidence of new memory formation during sleep. Thomas Andrillon and colleagues propose that these discrepancies may be due to the fact that different sleep stages are characterized by different types of brain activity, which could potentially explain why people sometimes could learn and sometimes could not. To test this hypothesis, the authors measured brain activity in sleeping participants and played them various sequences of sound. When the participants woke, they were tested on how well they were able to recognize the sounds they heard while they were asleep. Hearing the sequences during REM improved peoples’ performance on this task, whereas hearing the sequences during NREM sleep decreased performance. By analysing peoples’ responses to sounds during the night, the authors could confirm the learning effect in REM sleep. In NREM sleep, they observed a sharp distinction between light NREM sleep, during which learning was possible, and deep NREM sleep, during which learning was suppressed.

Taken together, these results not only show that you can learn during sleep but shed light on general memory processes and how they change during different sleep stages.

doi: 10.1038/s41467-017-00071-z


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