Although sleep appears to be a passive activity, it involves an active interplay of brain circuits; an activity that scientists and sleep experts have been studying for decades. Scientists have spent years studying sleep problems and the associations between sleep and learning. For instance, studies have shown that a person who has sleep problems and is sleep deprived can’t focus well enough to learn effectively. Studies have also demonstrated that sleep has a role in the consolidation of memory, which is vital for learning. Now, according to the Weizmann Institute, learning has been shown to occur during sleep.
The new research was published in the Nature Neuroscience journal. The research’s premise is based on Pavlovian theories of classical conditioning; classical conditioning involves pairing two elements, and conditioning people or animals to anticipate one element whenever they are exposed to the other element.
While participants slept, researchers of the Weizmann Institute played a tone of music and followed it with an odor to induce sniffing. Later, when the participants were awake, the researchers played the tone without presenting an odor. Despite having no conscious memory of hearing the tone, the subjects responded to the sound by sniffing, despite no odor being present. This demonstrated that a learned response had been acquired while the subject was sleeping.
Researchers then took this theory a step further to see if they could induce more than one learned response – to sniff deeply or to avoid sniffing. The subjects were grouped, and one group was exposed to a tone followed by a pleasant odor, while the other group was exposed to a tone followed by an unpleasant odor. When they awoke the next day, they heard the tones again. Although they had no conscious memories of having heard the tones before, the group that had been exposed to the pleasant odors inhaled deeply when they heard the tones while awake, while the other group took short, shallow sniffs when exposed to the tones in a waking state.
Sleep consists of 5 stages. Brain function alters throughout each stage. The last stage is called Rapid Eye Movement or REM and is characterized by increased respiration, increased brain activity, and quick eye movement. While the muscles become more relaxed, the brain and body systems become more active. The research team at the Weizmann Institute discovered that the learned response was more pronounced during the REM phase of sleeping.
Now that it has been established that some kind of sleep learning is possible, researchers want to find out just what information can be learned during sleep and what information can’t. They also want to investigate brain function and processing in altered states of consciousness, such as coma.
Doctors are constantly telling their patients to get a good night sleep. Sleep problems can decrease your performance at work, impact your reaction behind the wheel of a car, add stress to your relationships, affect your immune system, and create cognitive impairment. The Wiezmann study gives people another reason to focus on proper sleep. While researchers aren’t saying you can learn an encyclopedia of information while you sleep, they do believe there is enough evidence to suggest that new knowledge can be acquired while in a restful state.