Researchers are one step closer to finding the well from which consciousness springs, with the help of data gleaned from research done on epilepsy patients.
Finding Consciousness In The Brain
Out of the mysteries of the human brain, consciousness is the most enigmatic. After three decades of research into the matter, neurologists have yet to pinpoint a specific location in the brain that could be the source of human consciousness.
Research done by a team of neurologists at Tel Aviv University could at least shed some light on the matter. Although there is no telling yet what brain structures create consciousness, the new discovery points to two exact places in the brain where neural activity may point to clues about the emergence of conscious experience.
Studying Patients With Epilepsy
Consciousness is not an easy subject to study, even for the most skilled and knowledgeable minds in the field. When it is consciousness studying itself, one is bound to go around in loops.
Past scientific research has been limited to people who can provide accurate accounts of their subjective experiences. Moreover, much of the data is bound by indirect observations of brain activity through EEG and fMRI.
To gain a closer look, scientists have to get inside the actual brain, which would be too invasive even for researchers probing the origins of consciousness.
In a study published in the journal Nature Communications, the team led by neurologist Hagar Gelbard-Sagiv of the Sagol School of Neuroscience were able to get around this problem by working with people who already have electrodes drilled inside their brains.
Epileptic patients often have electrodes implanted to help doctors identify the parts of the brain causing seizures. For a few weeks, the implants would gather data about every single neuron in its vicinity.
By recruiting patients of epilepsy with the implants in their brain, Sagiv's team was able to analyze brain activity associated with the beginning of a conscious experience.
The researchers wanted to look at the exact moment where a person becomes conscious of a new experience. To do this, they devised an experiment that generates a phenomenon called binocular activity.
They presented the participants with two different pictures, one to each eye. The right eye, for example, was presented a house, while the left eye was presented a face.
In this situation, the brain will not be able to put the images together. The brain will have to choose which of the images it becomes conscious of. Every few seconds, the choice switches irregularly from one image to the next. The switch is involuntary even while the physical stimuli, the two images, are the same.
By doing so, the researchers were able to separate brain activity associated with the beginning of the consciousness of a new experience, as compared to brain activity associated with the processing of light from the visual stimuli.
The two processes of visual stimulation and actually becoming aware of what one is looking at almost always go together. However, the experiment allowed Sagiv's team to peel them apart and measure the timing of when each process happens.
Where Perception Begins
Each participant was required to let the researchers know the moment they become conscious of a new experience. It turns out the brain reacts much faster. The researchers saw the medial-frontal lobe lighting up two seconds before the participants said they became conscious of the new image. The medial temporal lobe is activated one second after.
"Two seconds is a long time in terms of neural activity," Sagiv says. "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 precept."