During an anesthetically induced unconscious state, the brain shows marked changes in activity; regions of the brain lower or cease communication with one another, and short bursts of heightened of activity occur in each of them individually. Unconscious brain activity also shows oscillating patterns, according to the Massachusetts Institute of Technology.
Using functional magnetic resonance imaging, researchers at the University of California Los Angeles uncovered similar findings to those from MIT, noting the same lack of communication between parts of the brain. They conclude that consciousness exists as a result of neural communication throughout the brain, according to PsychCentral. When a person falls unconscious, communication between neurons declines or ceases entirely.
Being knocked out due to brain trauma is generally the result of a concussion. A concussion is a neural impairment caused by a head injury and leads to different parts of the brain ceasing communication. Unconsciousness due to brain trauma is thought to result from the brain being jarred and shaken within the skull. If the damage to the brain outpaces its regenerative abilities, being knocked out is the result, according to Popular Mechanics. Dr. Anthony Alessi points out that the brain relies on sufficient amounts of blood flow in order to regenerate and recover from head injuries. He states that when the brain lacks the blood flow necessary to regenerate, unconsciousness results.