Jun 11, 2011 10:22 GMT  ·  By
This is a snapshot from a movie showing how brain activity changes when an anesthetic is injected in the body
   This is a snapshot from a movie showing how brain activity changes when an anesthetic is injected in the body

Researchers at the University of Manchester, in the United Kingdom, have shown for the first time how the human brain slips into a state of unconsciousness. Using an array of 32 electrodes, they were able to produce a 3D view of neural activity taking place as this happens.

One of the most important conclusions is that the connections forming between some particular groups of neurons seem to fade out of existence. As a result, a mysterious, sleep-like state occurs, which translates into lack of response to the environment when that person is viewed from the outside.

Science defines unconsciousness as the lack of awareness and response a person displays to stimuli in their surroundings. Even though the phenomenon has been with the human race since the latter developed, experts cannot yet explain how and why it happens.

For differentiation, consciousness is defined as being aware of one's surroundings, being able to respond to external stimuli, and also being able to process new information in typical thought patterns.

In the new experiments, researchers attached a group of 32 electrodes to the heads of volunteers, in order to track what was going on as a person became unconscious. Each of the electrodes was capable of taking about 100 readings per second.

The results further confirmed a theory set forth by University of Oxford expert Dr. Susan Greenfield, who argued that a dimmer switch-like process existed in the brain. This indeed appears to be the case.

“We have produced what I think is the first video in existence in the entire world of [the brain of] a patient being anesthetized. We are seeing different parts of the brain, different areas, being activated and deactivated,” says Manchester expert and study researcher Brian Pollard.

The dimmer switch theory proposes that certain groups of neurons interact while we are awake, allowing our brain to interpret information from the environment. When an anesthetic is injected into the body, the activity in these nerve cells subsides, and communications between them is inhibited.

Using the electrodes, the Manchester team was able to observe how this happened in real time. The achievement may pave the way for the development of new methods for monitoring head injuries, stroke or dementia in at-risk patients, LiveScience reports.