Researchers at The University of Manchester (UK) have been able to watch, for the first time, what happens to the brain as it loses consciousness.

Using sophisticated imaging equipment, they constructed a 3-D movie of the brain as it changes while an anesthetic drug takes effect.  The researchers said the real-time 3-D images seemed to show that losing consciousness involves a change in electrical activity deep within the brain, changing the activity of certain groups of neurons and hindering communication between different parts of the brain.

The team used a new imaging method called functional electrical impedance tomography by evoked response (fEITER) that enables high speed imaging and monitoring of electrical activity deep within the brain. The researchers examined 20 healthy volunteers and are now looking at 20 anesthetized patients scheduled for surgery. They said they hope to see 3-D images of the brain’s conductivity change in the anesthetized patients.

They also said their research supports the hypothesis of Professor Susan Greenfield (University of Oxford). “Our findings suggest that unconsciousness may be the increase of inhibitory assemblies across the brain’s cortex … [and] lend support to Greenfield’s hypothesis of neural assemblies forming consciousness,” said researcher Brian Pollard.

Their work is being presented at the European Anaesthesiology Congress in Amsterdam.