During sleep the brain's reaction to sound remains strong, but one critical feature of conscious attention disappears

New research may provide a key to a scientific enigma: How does the awake brain transform sensory input into a conscious experience? The groundbreaking study relied on data collected from electrodes implanted, for medical purposes, deep in the human brain. The information was utilized to examine differences between the response of the cerebral cortex to sounds in sleep vs. wakefulness, at a resolution of single neurons.
http://dlvr.it/STng60