General anesthesia and normal sleep affect brain in an amazingly similar way as consciousness fades

What happens in the brain when our conscious awareness of the surrounding world and of ourselves fades during general anesthesia and normal sleep? This fundamental question was studied with novel experimental designs and functional brain imaging by Finnish scientists. They succeeded in separating the specific changes related to consciousness from the more widespread overall effects, commonly misinterpreted as the neural correlates of consciousness. The effects of anesthesia and sleep on brain activity turned out to be surprisingly similar. These novel findings point to a common central core brain network that is fundamental for human consciousness. Explaining the biological basis of human consciousness is one of the greatest challenges of science. While the loss and return of consciousness, as regulated by drugs or physiological sleep, have been employed as model systems in the study of human consciousness, previous research results have been confounded by many experimental…