Our brains are amazing objects. The most complex thing in the known universe, there is still so much we don’t know about what is going on inside our skull, but researchers might have just got a step closer to solving one of the most enduring of mysteries: the origin of consciousness.
“Computers and robots interact with the world without being conscious. But something miraculous happens inside our brains to make us conscious and experience the world from a subjective perspective,” explained neurobiologist Dr Hagar Gelbard-Sagiv. “Despite 30 years of neuroscientific research in this area, we still do not know which areas of the brain take part in the process.”
But along with her colleagues at Tel Aviv University, Dr Gelbard-Sagiv may have got a glimpse at what goes on in the brain during the emergence of a conscious experience. Publishing their results in Nature Communications, the researchers were able to pinpoint exactly where this takes place among the cacophony of other neuronal activity firing through the dense network of matter in our brains.
The team were able to peer into the inner workings by taking advantage of patients who were being treated for epilepsy. In order to determine exactly where in the brain seizures are originating, doctors will sometimes insert electrodes deep into the brains of epileptic patients, and record the activity.
This provides a rare and intimate insight into the goings on of their brains for researchers such as Dr Gelbard-Sagiv, offering a much better view than more conventional methods such as electroencephalography and fMRI scans. While those methods effectively allow the scientists to sit on the outside and look in, by testing patients with brain implants they can see what is going on from the inside.
For the study, they conducted an experiment known as “binocular rivalry”, in which patients are shown one image to one eye, and a different image to the other. If the images are radically different, such as a house and a face, the brain cannot combine them and so the subject is forced to see one or the other, which alternates at irregular intervals.
What they found was that the brain activity in the frontal lobe changed almost a full two seconds before the patients reported the image switching, and the activity in the medial temporal lobe around a second beforehand.
“Two seconds is a long time in terms of neural activity,” said Dr Gelbard-Sagiv. “We believe that the activity of these neurons not only correlates with perception, but also may take part in the process that leads to the emergence of a conscious percept.”
By watching in real time as one conscious experience is replaced by another, the researchers have inched closer to understanding where it originates.
