The Real Cognitive Neuroscience Behind ‘Severance’

THIS ARTICLE IS republished from The Conversation under a Creative Commons license.

Severitywhich imagines a world where a person’s work and personal life are surgically separated, returns Friday for its highly anticipated second season. While the concept of this appealing piece of science fiction is far-fetched, it touches on a question that neuroscience has been trying to answer for decades: Can a person’s mind really be split in two?

Remarkably, “split-brain” patients have existed since the 1940s. To control the symptoms of epilepsy, these patients underwent surgery to separate the left and right hemispheres. Similar surgeries it still happens today.

Research later on this type of surgery showed that the separate hemispheres of split-brain patients could process information independently. This raises the unknowable possibility that the procedure creates two separate minds living in one brain.

In the first season of SeverityHelly R (Britt Lower) experienced a conflict between her “innie” (the side of her mind that remembered her work life) and her “outie” (the non-work side). In the same way, there is evidence of a conflict between the two hemispheres of real split-brain patients.

When speaking with split brain patients, they usually communicate with the left hemisphere of the brain, which controls speech. However, some patients can communicate from their right hemisphere by writing, for example, or arranging Scrabble letters.

A young patient in a study He was asked what profession he would like in the future. His left hemisphere chose an office job to make technical drawings. His right hemisphere, however, arranged letters to spell “car racer.”

Split-brain patients also reported “foreign hand syndrome“, where one of his hands is perceived to be moving of its own volition. These observations suggest that two separate conscious “persons” can coexist in one brain and can have conflicting goals.

In Severityhowever, the innie and the outie have access to the word. This is an indicator that the fictitious “separation procedure” must involve a more complex separation of brain networks.

An example of a complex separation of functions was described in Neil’s case reportin 1994. Neil was a teenage boy who had a number of difficulties after a tumor of the pineal gland. One of these difficulties was a rare form of amnesia. It meant that Neil could not remember the events of his day or relate what he had learned at school. He had also become unable to read, although he could write, and he was unable to name objects, although he could draw.

Astonishingly, Neil managed to maintain his education. The researchers were interested in how he was able to complete his schoolwork despite having no memory of what he learned. They questioned him about a novel he was studying at school, Cider with Rosie by Laurie Lee. In the conversation, Neil couldn’t remember anything about the book, not even the title. But when a researcher asked Neil to write down everything he could remember about the book, he wrote “Bloodshot Geranium windows Cider with Rosie Dranium smell of humid peppar (sic) and mushroom growth” – all words connected to the novel. As Neil could not read, he would ask the investigator, “What did I write?”