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Man loses fear of spiders with chunk of his brain

Brain surgery meant to eliminate seizures had a stunning side effect for a man who was terrified of creepy crawlies.

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Kevinbercaw/Wikimedia Commons

When a 44-year-old man had brain surgery, his fear of spiders was probably the furthest thing from his mind. But when he woke up, according to a fascinating account from New Scientist, his crippling arachnophobia was gone, along with a portion of his amygdala, a nerve center located in the base of the brain.

The businessman had been suffering from seizures caused by sarcoidosis, an inflammatory disease with unknown causes that can damage the brain and other organs.

The surgery to remove a portion of the left amygdala, a region of the brain well-established for its role in processing scary stimuli, took away the seizures but also eliminated something else -- the man's fear of eight-legged creepy crawlies. In fact, the fear was so utterly obliterated that man now says he finds spiders fascinating and can view them up close and even touch them.

Interestingly, the surgery didn't remove the man's other less acute fears, like that of speaking in public.

One of the doctors who worked on the case, Nick Medford of the UK's Brighton and Sussex Medical School, told New Scientist it's tough to know just how the operation eliminated a very specific fear, but he believes it might have to do with the fact that our brains handle two different kinds of response to fear.

"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," said Medford, who has detailed the case in a paper for the journal Neurocase. "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."

His hunch is that in removing the left part of the amygdala, the "quick and dirty" fear response was neutralized, while the longer-term fear center was kept in tact.

While this might seem like good news to phobia sufferers, unfortunately, Medford says the amygdala is located too deep in the brain to be zapped by non-invasive techniques like light stimulation to blast away our fears. Surgery's the only way to reach it, and going under the knife to become less afraid of otters (lutraphobia) or knees (genuphobia) probably isn't the wisest move.

Still, the accidental discovery does help enhance our understanding of how the brain works, and Medford says he'll be on the lookout for similar reactions in future surgeries. "It's not uncommon for people to have temporal lobe surgery for severe epilepsy. And arachnophobia is supposed to be reasonably common," he said. "So we might be able to test people for that phobia, or any other kind, before and after surgery."