The 60s was filled with mini skirts, free love, and experimental brain surgery. Wait what? Yep. First used in the 1940s to cure epilepsy, a radical procedure called corpus callosotomy was starting to make waves in the swinging 60s. It involved cutting the delicate fibres that connect both sides of the brain. It wasn’t an immediate success (surprise, surprise), but, in 1961, researchers began to see results. They rolled out the treatment to a handful of patients, and quickly became aware of an intriguing ‘side-effect’ - one that’s had scientific minds spinning for decades.
After severing the connection between the two sides of the brain, the patients began to exhibit strange reactions to everyday tasks. In short, it was as if they had two minds, each operating without the other side’s input. For example, one patient remembers shopping for groceries. It was as if her right and left hands had completely different agendas when she tried to take a can of food from the shelf.
The reason for the confusion lies in how each side of the brain operates. The left side of the brain controls the right side of the body, and vice versa. But both sides have different jobs. You’ve probably heard that your right brain is more ‘creative’ and your left brain is more ‘analytical’. Well, this is true, but it’s more nuanced than that. The left side typically deals with language and the right deals with spatial skills. When data arrives at the brain, it travels across both sides, allowing all the information to be decoded by the department best suited for the job. When the communication cable is cut between the two hemispheres, data that gets fed into one side doesn’t have access to the tools on the other.
At first glance, both sides of the brain appeared to be operating separately, as if they were different entities. But after years of studies, scientists realised that our brains are a carefully constructed network of tools, each providing a different view or interpretation of the world around us.
Researchers were able to study the effects of the procedure by flashing images in either the right or left field of vision - each side sends data to the opposite hemisphere. When they flashed the image of an apple to the left field of vision, the patient would struggle to name it, but could locate it in a box using his hand. The fact that he couldn’t ‘name’ the apple didn’t mean he couldn’t recognize it. After all, to name an apple or to point to one are both equally important methods of ‘labeling’. When all of these tools are combined, it’s clear to see how incredibly complex the brain is.
Split-brain syndrome has fascinated scientists for decades, and provided a glimpse into how and why our grey matter, matters.
Image by Robina Weermeijer