Birth of consciousness in brain
Italian team pinpoints origin of consciousness Rome, September 29 – Italian researchers have discovered the “birthplace” of consciousness, a breakthrough that could eventually help cure a variety of medical conditions. While it has long been accepted that consciousness develops in a certain part of the brain, Marcello Massimini and Giulio Tononi have located its precise […]
Italian team pinpoints origin of consciousness
Rome, September 29 – Italian researchers have discovered the “birthplace” of consciousness, a breakthrough that could eventually help cure a variety of medical conditions.
While it has long been accepted that consciousness develops in a certain part of the brain, Marcello Massimini and Giulio Tononi have located its precise point of origin.
In a study to be published in the next issue of the international weekly Science, the two experts claim that it is “formed” by rapid, mutual communication between the upper, cortical areas of the brain. “We’ve known for some time that certain areas of the brain are fundamental for generating consciousness, while others are not,” explained Massimini, who works at Milan University .
Together with Tononi, an Italian psychiatrist at the American University of Wisconsin-Madison, he embarked on a series of experiments based on Tononi’s theory that consciousness is dependent on the brain’s ability to integrate information .
In practical terms, this means that certain parts of the brain must be able to “talk” to each other .
For example, individuals with injuries to the spinal chord or cerebellum do not lose consciousness. On the other hand, damage to the outer part of the thalamus, a central region in the brain, can induce a loss of consciousness that is sometimes permanent, as in the case of comas .
In a bid to understand what goes on in the brain when people lose consciousness, Tononi and Massimini looked at a reversible form of unconsciousness: sleep “At the start of the night, when we fall into a deep sleep, we and the universe around us ‘cease to exist’,” explained Massimini .
“Yet the paradoxical element is that while our consciousness vanishes, the brain remains alert and very active.” Using a new technique developed in Finland, the pair proved that consciousness is lost during sleep owing to a lack of communication between various different parts of the cerebral cortex .
They first applied continual, low-grade stimulation to awake, healthy individuals in a very tiny section of the brain, using a technique known as transcranial magnetic stimulation (TMS) .
The next stage involved measuring the spread of the stimulus with a high-resolution electroencephalogram (hr-EEG). “The result was crystal clear and absolutely extraordinary,” said Massimini .
When the subjects were awake, the stimulus lasted as long as 300 milliseconds, while it spread for just 100-150 milliseconds during deep sleep, showing that the brain is incapable of transmitting stimuli to other sections while in this state .
This lack of connection between different cortical areas during sleep is vital in explaining the transition from consciousness to unconsciousness, according to Massimini .
The combination of TMS and hr-EEG could eventually be used to create a kind of “index of consciousness”, helping doctors make critical decisions in controversial “vegetable” cases, he said .
While such developments are still some time in the future, he and Tononi believe their discovery could have more immediate applications in a variety of fields .
Testing has already started on schizophrenic subjects, in the hope it could eventually help treat the condition, but it could also be used to evaluate comas or even maintain closer checks on patients under anaesthesia, he said .
