What happens when your brain loses consciousness
A mysterious sleep-like state occurs as electrical activity deep in the brain dims and connections between certain neurons suddenly break down.
Washington: For the first time scientists claim to have developed new 3-D images which can reveal the electrical activity deep inside the brain when a person is unconsciousness.
Researchers at the University of Manchester said the new imaging technique shows that a mysterious sleep-like state occurs as electrical activity deep in the brain dims and connections between certain neurons suddenly break down.
"We have produced what I think is the first video in existence in the entire world of [the brain of] a patient being anaesthetised," said study researcher Brian Pollard.
"We are seeing different parts of the brain, different areas, being activated and deactivated," he was quoted as saying by LiveScience.
Loss of consciousness occurs when the brain is no longer aware of one`s surroundings and so the body stops reacting to the world around it. Scientists and doctors aren`t sure how this happens.
Dr Susan Greenfield of the University of Oxford had earlier suggested that our brains are on a "dimmer switch", suggesting that when a person is awake, certain groups of brain cells interact and work together to decipher information sent to the brain.
When this "dimming switch" gets turned down -- as can be happen with an anaesthetic drug -- these brain-cell interactions don`t work as well together and communication
between the groups is inhibited.
In the new research, presented recently at the European Anaesthesiology Congress, the new imaging method allowed the researchers to monitor the electrical activity deep inside the brain in real time through 32 electrodes on the head of each study participant.
Because the electrodes monitor this activity 100 times per second, the researchers were literally able to watch as patients went from awake to an unconscious state.
With the technique, the team has studied the brain activity in 20 healthy adults, who will serve as controls; the researchers will compare the brain activity of controls with
that of patients undergoing surgery (and being "put under"), so they can get a better handle on how a person loses consciousness.
They have studied 17 patients losing consciousness so far, and all show similar patterns of activity deep within the brain.
Pollard could even see unconscious patients` visual cortex working when he appeared in their frame of view.
"The patient is lying still and quietly and there is some activity in the right hand side of the brain, what we suspect is the visual cortex," Pollard said.
"We observed in the brain the patient seeing me. We aren`t entirely certain what it means. We are seeing it for the first time."
The device could be useful for monitoring head injury, stroke or dementia patients, to see how their brain activity changes with their condition, Pollard added.