Do you think when you sleep? Not dreaming, but actually thinking and processing information. People have often thought that the brain shuts down the majority of its activity during sleep, however, recent studies suggest that this may not be true. The brain allows some sensory information to continue entering during sleep, which explains why people are able to hear alarms and shouts during the night. However, through a new brain activity study, scientists have found that the brain is also capable of making decisions while a person is asleep.
The study began by having people sort words into two categories, animals or objects. When a participant heard a word, then then pressed a button to place the word into one of the two classes. EEG electrodes were placed on each participant’s head to monitor brain activity.
We know that the brain cannot begin a new activity during sleep because the reticular activating system that allows people to be alert and conscious is inhibited. Therefore, the study had to begin while the person was awake. The sorting activity began while a person was awake, but in a dark room. The darkened room encouraged the participants to fall asleep while sorting. Most of patients gradually fell asleep during the activity. While asleep, the subjects were still able to hear to words being called out for each object. Even though they could not physically push the button on either side to sort the words, their brains still planned out the movement!
Using the EEG, scientists were able to look at the motor area in each hemisphere of the brain to see which response the brain was planning for each word. This study shows that the brain was able to continue preparing to sort the words in the correct way while sleeping! Future research can now be done to see just how much the brain can learn during sleep. However, this may not be completely beneficial as humans need to allow their brains to rest in order to keep up with day to day living.
- How your brain actually makes decisions while you sleep (Washington Post, Sept 17th)
- Kouider S., Leonardo S. Barbosa, Louise Goupil & Tristan A. Bekinschtein (2014). Inducing Task-Relevant Responses to Speech in the Sleeping Brain, Current Biology, 24 (18) 2208-2214. DOI: http://dx.doi.org/10.1016/j.cub.2014.08.016