Researchers Find Learning in Sleep Possible

A new study finds that learning through sleep is possible by processing tones and odor.

Researchers Noam Sobel and Anat Arz from the Weizmann Institute in Israel have found that it is possible for people to gain new knowledge while they are asleep. They monitored the sleep state of the subjects who were asked to sleep in special labs to study the brain's process. First, the experts presented a tone when the subjects were asleep followed by a pleasant odor. Then, they played a tone that was followed by a bad smell. This experiment was continued for sometime during the night with tones and odors following each other.

Later, they just played the tones with no odors following them. Odors were used in tests as the sleeping brain acts the same manner when one is either asleep or awake.

In this new study, the experts found that the subjects were able to associate the tones with the odor and responded when just the tones were played not accompanied by the odor. While the subjects inhaled deeply when the tone that was followed by a pleasant odor was played, they sniffed and took shallow breaths on hearing the tone associated with the bad smell.

When the tones were presented the following day with no odor, the subjects responded the same way when they were asleep - with either deep breaths or short sniffs - associating with the pleasant and bad odor.

However, tests performed to find out about verbal sleep learning have failed to show any new information learnt by the subjects.

Another experiment was conducted to study about sleep learning during Rapid Eye Movements (REM) and non-REM. It was found that the memory combined the tones and the odors during the non-REM movement, which might play a significant role in sleep learning.

According to the researchers, "dream-amnesia", which makes people to forget their dreams, might be operating during the REM stage of sleep cycle preventing to learn new information.

While earlier studies have shown that brains can process information during sleep, researchers now intend to probe the process of the brain in different changing states such as sleep and coma. "Now that we know that some kind of sleep learning is possible," Arzi said in a statement, adding: "we want to find where the limits lie - what information can be learned during sleep and what information cannot."

The findings of the study are published in the journal Nature Neuroscience.