Want to learn something? Sleep on it, but not too deeply: study

The human brain can learn only in certain phases of shut-eye
The human brain can learn only in certain phases of shut-eye

Scientists fascinated by the idea that humans might be able to learn while asleep—a new language, say, or a piece of music—have long been coming up with clashing experimental results.

On Tuesday, a team said it has finally unravelled why. The human brain can learn only in certain phases of shut-eye.

Participants in a study were able to memorise sound patterns played to them during two phases of sleep called Rapid Eye Movement (REM) and N2, researchers wrote in the journal Nature Communications.

REM is the phase of unconsciousness during which we typically dream, and is characterised, as its name suggests, by the eyes flitting about restlessly. N2 is a phase of lighter, non-REM sleep.

A third of deep non-REM sleep called N3, said the researchers, was positively bad for formation, however.

"Sounds previously learned during N2 sleep are forgotten or unlearned, as if erased from memory," the French team said in a statement.

They had wired 23 volunteers up to EEG brain monitors, and played them recordings of while they slept.

When they awoke, the trial participants were tested on how well they could remember the simple compositions.

Are learning and unlearning bedfellows?
Participant of a sleep experiment equipped with an electroencephalogram. The electroencephalogram records brain's electrical activity and allows to determine in real time whether a person is awake or asleep. Response handles placed in participants' hands allowed them to categorize the sounds presented during the experiment. Credit: Scientifilms

The team "observed a sharp distinction between light NREM sleep, during which learning was possible, and deep NREM sleep, during which learning was suppressed," said a press summary by the journal.

In fact, upon waking, the participants who unlearnt the sounds during N3 sleep found the same patterns even harder to relearn than to pick up completely new ones.

This supported theories that N3 sleep serves to unclutter the memory, said the researchers.

Further research must be done to determine how the findings may find practical application as a learning aid.


Explore further

Sleeping brain's complex activity mimicked by simple model

More information: Thomas Andrillon et al. Formation and suppression of acoustic memories during human sleep, Nature Communications (2017). DOI: 10.1038/s41467-017-00071-z
Journal information: Nature Communications

© 2017 AFP

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Aug 08, 2017
The study shows sleep phases' effects on sounds played *while sleeping in that phase*. While we'd love to learn how to memorize experiences we sleep through, that case seems largely academic. Why didn't they play the sounds while people were awake and paying attention, then monitor the people for their sleep phases, and study the recall of people found to have gone through only one or another phase?

Aug 09, 2017
I always thought it was peculiar that I seemed to pick up french despite falling asleep in class --every time--.

Aug 09, 2017
I always thought it was peculiar that I seemed to pick up french despite falling asleep in class --every time--.


So? How's your french doing?

Aug 09, 2017
Grallen:
I always thought it was peculiar that I seemed to pick up french despite falling asleep in class --every time--.


I wonder if all the people falling asleep listening to Fox News explains how its fake news is retained by the population.

Researchers have now shown methods for imprinting memories while sleeping, with different effectiveness ratings for different sleep phases. A very interesting study would show the comparative effectiveness of imprinting facts vs fallacies, in each of various phases: different sleep phases, and different woke phases like full attention, distracted, background.

Though I expect propaganda media outlets would exploit the results better than either education or audiences would. Fox News would totally recalibrate to it, to say nothing of its even worse pursuers.

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