Introducing the brain: where consciousness happens (Introduction)

by David Turell @, Thursday, June 14, 2018, 21:45 (102 days ago) @ David Turell

An intimate look in epileptic brains where consciousness happens:

https://www.sciencedaily.com/releases/2018/06/180613113751.htm

"A new Tel Aviv University study takes researchers a step closer to solving this mystery. The study, drawn from data collected by electrodes implanted in patients with epilepsy, identifies and measures the neural activity associated with a new conscious experience.

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"Because the conscious experience is private and inaccessible to observers, it is mostly studied in people who are capable of reporting their subjective experiences. Moreover, researchers are often limited to indirect measures of brain activity, such as EEG and fMRI. Here, the researchers took advantage of a unique medical opportunity: the surgical implantation of electrodes in the brains of patients with epilepsy to determine the precise areas responsible for their seizures. Patients were monitored for a week or two, until enough data on their seizures had been collected. During this time, the implanted electrodes recorded the activity of individual neurons in their vicinity.

"The researchers presented two different images to the patient, one to each eye, to probe the moment in which a new experience arises. For example: An image of a house was presented to the right eye and an image of a face to the left eye. In this situation, known as "binocular rivalry," the brain cannot combine the two images. Instead, the subject sees either the house or the face, and this alternates irregularly every few seconds. These alternations happened involuntarily, while the physical stimulus remained constant. This allowed researchers to isolate brain activity related to the change in perception and differentiate it from brain activity related to the physical stimulus.

"The scientists discovered that the activity in frontal lobe neurons changed almost two seconds before the patient reported an alternation in perception, and that the neuronal activity in the medial temporal lobe changed one second before a report.

"'Two seconds is a long time in terms of neural activity," Dr. Gelbard-Sagiv said. "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."

"'The study captures individual cells in the human brain just before one conscious experience is replaced by another," Prof. Fried said. "It is a unique privilege to gain such a rare glimpse into human consciousness. "

Comment: The long delay in time indicates to me other parts of the brain got into the action to produce he conscious experience.


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