Sleep Doesn't Stop the Brain: Words Are Still Being Classified

Of course, we know that the brain remains active as we sleep. The subconscious remains active even as we're far off in dream land.

Now, recent findings published in the journal Current Biology show that that the brain is unconsciously classifying words as we sleep, as well.

"We show that the sleeping brain can be far more 'active' in sleep than one would think," said study author Sid Kouider of Ecole Normale Supérieure, in a news release. "Far from falling [into] a limbo when we fall asleep, parts of our brain can routinely process what is going on in our surroundings and apply a relevant scheme of response. This explains some everyday life experiences such as our sensitivity to our name in our sleep, or to the specific sound of our alarm clock, compared to equally loud but less relevant sounds."

The study extends off of earlier work on subliminal processing that examines speech processing and how other complex tasks "can be done not only without being aware of what you perceive, but [also] without being aware at all," according to researchers.

For their findings, the study authors used an EEG on human participants while they were awake and instructed them to classify spoken words between both animals or objects. Eventually, they were put in the dark to recline comfortably with their eyes closed while the classification task was continued as they drifted off to sleep.

Findings revealed that as they were asleep, participants continued to accurately respond, although more slowly.

Researchers believe that with future studies, they can further determine the effects of sleep and just how the brain comprehends different things as we sleep.