New research on the biological basis of consciousness found that the loss and return of consciousness is linked to the same network of brain regions for both sleep and anesthesia.
In a paper published in Jneurosci today, University of Turku scientists explain how they searched for networks associated with human consciousness by measuring the brain activity of adult males with positron emision tomography as they fell asleep and went under anesthesia. The team led by Annalotta Scheinin woke participants mid-experiment to interview them and confirm their state of connectedness.
They found that changes in connectedness corresponded to the activity of a network comprised of regions deep inside the brain: the thalamus, anterior and posterior cingulate cortex, and angular gyri. These regions exhibited less blood flow when a participant lost connectedness and more blood flow when they regained it. The pattern held true for both sleep and anesthesia, indicating the changes corresponded to connectedness rather than the effects of sleep or drugs, and that the network may be imperative for human consciousness.