Medical imaging studies have shown that the region of our brain called the amygdala plays a big role in the neural network that mediates specific phobias -- among them, arachnophobia. New Scientist reports on the curious case of a 44-year-old business man who abolished his lifelong fear of spiders by having that part of his brain removed.
It was actually more of a serendipitous side effect. The man starting having seizures out of nowhere, and his brain scans revealed an abnormality in his left amygdala -- which is, more generally, involved in emotional reactions. Additional tests showed that it was caused by a rare condition called sarcoidosis, where the body’s inflammation response doesn’t go away, and immune cells cluster together to form lumps called granulomas. These can damage organs like the skin, lungs, lymph nodes, and sometimes the brain.
His surgeons decided to remove his left amygdala in a procedure called a left temporal mesial lobectomy. It went smoothly, but he started having a peculiar, visceral aversion to music, and he was suddenly no longer scared of spiders. As Washington Post describes, he went from being afraid to smash the crawlies with his hand to wanting to touch them and watch them up close.
His aversion to music abated over time, but his arachnophobia appears to be gone for good. As far as anyone knows, this is the first time a specific phobia vanished overnight when part of the temporal lobe was removed. The work was published in Neurocase.
It’s difficult to know just how one phobic response was singled out and plucked off, according to Nick Medford from the Brighton and Sussex Medical School in the U.K. Having observed the man, Medford thinks it has to do with our two different types of fear response. "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 tells 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."
The lobectomy didn’t change any of his other fears or anxieties. So in this case, a part of his panic-fear response appears to have been purged, while his more general fear responses remained intact.
However, this case likely won’t lead to a cure any time soon: The amygdala is too deep in the brain to mess with non-invasively. But not all is lost! Because both arachnophobia and brain surgery for severe epilepsy are fairly common, researchers could try to keep track of these various causes and effects. That could help them figure out where our deepest, darkest fears are stored -- and how to slice them out safely.
[Via New Scientist]
Image: Renato Lombardero via Flickr CC BY 2.0