Learning While You Sleep?

Sleeping minds may not be aware of it but they may still be learning

(RxWiki News) A good night’s sleep can help your memory to be strong. But can we make new memories while we sleep? A recent study trained people while they slept.

The researchers paired a sound with a smell. The study participants learned to sniff after hearing the tone – even when the smell was not there.

For some, learning carried over into their waking life, but they were not aware of it.

"Talk to your doctor about healthy sleep habits."

Anat Arzi, a graduate student in the Department of Neurobiology at Weizmann Institute of Science in Israel, with Noam Sobel, PhD, looked to see if learning could happen during sleep.

They took advantage of the fact that people will automatically sniff in certain ways when an odor is present.

When people smell something pleasant, they take big, long breaths. When they smell something bad, they use short, shallow sniffs.

While people slept, they presented odors to people just after a tone was played.

Throughout the night, they paired the tone and the smell at different times. They sometimes played the tone without the odor.

They only used the results of people that slept through the night – anybody that woke up during training was not included.

People in this study learned to sniff in response to the tone. Throughout the night, they learned that the tone was followed by a smell, and they started to sniff after the tone – even when there was nothing to smell.

Later, when people in the study were awake, they also sniffed after hearing the tone event thought they were not aware they had learned anything.

Then the researchers looked at how learning during sleep was related to the phase of sleep.

Learning was stronger during rapid eye-movement (REM) sleep. REM sleep is the active dreaming phase.

The learning only carried over into waking if they had learned to sniff during non-REM sleep. Non-REM sleep is the time when memory consolidation happens.

In a recent press release, Anat Arzi said, “Now that we know that some kind of sleep learning is possible we want to find where the limits lie – what information can be learned during sleep and what information cannot.”

This study was published August 26 in Nature Neuroscience. The authors report no competing interests.

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Review Date: 
September 6, 2012