Researchers have for the first time used sophisticated imaging equipment to construct a 3-D movie of the brain, that shows how the journey from consciousness to unconsciousness takes place following the usage of an anesthetic drug.
Brian Pollard, Professor of Anaesthesia at The University of Manchester (UK), is now due to report to the European Anaesthesiology Congress in Amsterdam, telling it how the real-time 3-D images show a change in electrical activity while the brain loses consciousness, changing the activity of certain groups of nerve cells (neurons) and hindering communication between different parts of the brain.
The team used an entirely new imaging method called 'functional electrical impedance tomography by evoked response' (fEITER *), which aids high speed imaging and monitoring of electrical activity deep within the brain and helps researchers measure brain function.
The machine itself is a portable, lightweight monitor, which can fit on a small trolley. It carries out an 'electronic scan' in 100 times of a second.
The speed of the response of fEITER is such that the evoked response of the brain to external stimuli, such as an anesthetic drug, can be captured in rapid succession as different parts of the brain respond, thus tracking the brain's processing activity.
"We have looked at 20 healthy volunteers and are now looking at 20 anaesthetised patients scheduled for surgery. We are able to see 3-D images of the brain's conductivity change, and those where the patient is becoming anaesthetised are most interesting," said Prof Pollard.
"We have been able to see a real time loss of consciousness in anatomically distinct regions of the brain for the first time. We are currently working on trying to interpret the changes that we have observed," he added.