Now scientists at Rutgers University, Newark and University of California Los Angeles (UCLA), have found a way to use functional magnetic resonance imaging (fMRI), and can peer into the brain to uncover accurately how information is processed before reaching awareness.
"It’s the same principle experienced during a car accident. The car accident actually happens tens of a milliseconds before you are aware you have actually been hit," explained Stephen Jose Hanson, psychology professor at Rutgers, who led the study.
"By looking at the back of the brain, we can ’read out’, for example, that a person is looking at dogs and cats before they actually know they are looking at a dog or a cat," he added.
The research also suggests that a more comprehensive approach is needed for mapping brain activity and that the widely held belief that localized areas of the brain are responsible for specific mental functions is misleading and incorrect.
In the recent past, much of neuroimaging has focussed on pinpointing areas of the brain that are uniquely responsible for specific mental functions, such as learning, memory, fear and love.
But this latest research shows that the brain is more complex than that simple model. In their analysis of global brain activity, the researchers found that different processing tasks have their own distinct pattern of neural connections stretching across the brain, similar to the fingerprints that distinctively identify each of us.
Rather than being a static pattern, however, the brain is able to arrange and rearrange the connections based on the mental task being undertaken.
"You can’t just pinpoint a specific area of the brain, for example, and say that is the area responsible for our concept of self or that part is the source of our morality," said Hanson.
The findings, based on a study of 130 volunteers, could also pave the way for earlier diagnosis and better treatment of mental disorders, such as autism and schizophrenia, by offering a means for identifying very subtle abnormalities in brain activity and synchrony.