After brain surgery, a 44-year-old man’s lifelong fear of spiders disappeared, according to a new paper in Neurocase: The Neural Basis of Cognition. This was the accidental result of a procedure to remove his damaged left amygdala, which seemed to be causing the mysterious seizures he’d recently started having.
Previously, the man’s methods of dealing with spiders involved keeping his distance: He’d throw tennis balls at them from across the room, or blast them with hairspray until they shriveled and died. Now he finds the critters fascinating and will go so far as to pick them up so he can observe them more closely.
The amygdala, a structure located deep within the brain, is associated with emotional reaction, and this could help explain why he lost his fear of spiders. Nick Medford, a psychiatrist at the Brighton and Sussex Medical School who observed the patient, explains in the paper that we seem to have two different kinds of fear responses. “It’s like when you see a snake and you jump back in alarm, but when you look back you realize it’s just a stick,” he told New Scientist. “That’s your quick-and-dirty panic response: it isn’t very accurate but it’s necessary for basic survival. And then there’s the more nuanced fear-appraisal, which takes longer to process but is more accurate.”
So it seems that in removing the damaged bits of the left amygdala, surgeons may have inadvertently also removed the part of the brain responsible for those panicky responses to fear. Unfortunately, this isn’t really a realistic treatment for phobias, because the amygdala is located so deep within the brain that a surgery aimed at it would be invasive and potentially dangerous. This appears to be a singular and unique case of an arachnophobia-ectomy.