The curious case that led to the discovery that we all have "two brains"

Mike Gazzaniga, the "father of split brain syndrome," spoke to the BBC about the case that allowed us to start seeing what was going on in our heads.

"Suddenly, you sit down and you say," Wow … is it possible that there are two spirits? "

What had happened so that Mike Gazzaniga, professor of psychology at the University of California at Santa Barbara, was so surprised and came to consider something then unsuspected?

"It was 1961 … can you believe it?", Gazzaniga tells the BBC, referring to the start of the investigation that would lead him to obtaining the curious title of "father of the split brain syndrome ".

What he observed sparked his interest.

"Then we spent about 50 years trying to understand that," he laughs.

At that time, 58 years ago, some serious cases of epilepsy were treated by dividing the brain.

The surgery consisted of cutting the main connections between the left and right hemispheres of the patient's brain.

The end result did not seem particularly detrimental, despite the fact that the patients worked effectively the rest of their lives with two separate brains.

One patient, identified as WJ, underwent this procedure at the California Institute of Technology (Caltech), where Gazzaniga worked as a researcher.

"I took him to a room where there was a sign where we could project information," says Gazzaniga.

"It turns out that if you or I or someone else is staring at a point, everything that appears to the left of that point goes into the right hemisphere of the brain and all to right goes to the left ", explains

"It means that if I show you the image and you are a person with a normal brain connection, you can name it to the left or to the right."

"What we discovered that afternoon was that WJ could name everything on the right.

"But I had no idea what was happening on the left."

Not only that: WJ did not know what we had planned to the left of the fixed point, but when we tried to communicate it otherwise, we realized that I could do it if I did not have to say the word .

"In fact, he showed that he could answer correctly by pointing his left hand."

WJ's right hemisphere was perfectly aware of what he had seen, but he could not communicate it to the left hemisphere, which is generally dominant for language and math skills.

Nevertheless, WJ could indicate what he knew from the left hand.

Why does it give us a headache if the brain does not feel the pain?

There were many other experiences, such as that of patient NG, who was shown a spoon on her left.

When asked what he had seen, he replied, "Nothing."

Then they asked him to place his left hand in a concealed compartment under the desk and, among all the present objects, to locate only with the touch what he had not seen.

After probing other objects, her right hemisphere has identified the spoon without hesitation.

However, the leftist still did not know – or can not say – what he had in his hand.

Then they asked him to guess what he wanted, to see what was going on.

NG laughed and said, "A pencil."

"When we did these experiments, we said we had created two minds," Gazzaniga told the BBC.

"Over the years, we learned that there were really many minds and that there were all kinds of areas in the brain."

"And that after the first cut, which separated the right and left, we observed, that was what each half of the brain with its aggregates could do."

"It turned out that they were different, although there were individual variations," says the researcher.

"But there are general principles."

In Gazzaniga's words: "The divided brain gave us the technique to see what was going on there and understand the nature of this organization."

We are not all exactly the same, but many of us are very similar.