If you're like me and you're terrified of spiders in a country where huntsmans almost as big as your face habitually crawl into your house through your bathroom window, you'll know that living with a phobia can be more than just an inconvenience. 

Whether it's a fear of heights, creepy crawlies, open spaces, or dogs, phobias can either arise because of a bad experience - a phenomenon known as conditioning - or they could have been passed down to you at a very earlier age by your parents, either by genetic inheritance or observed behaviour. Either way, once you have a phobia, it can be very difficult to 'unlearn' it.

But for the first time, a man has had his life-long fear of spiders effectively cut out of his brain, rendering him indifferent towards the leggy arachnids overnight. 

According to Helen Thompson at New Scientist, the middle-aged man had suddenly started having seizures, and brain scans revealed an abnormality in his left amygdala - a region in the brain's temporal lobe that's thought to control the processing of conscious emotions. The cause of the abnormality turned out to be a rare inflammatory disease known as sarcoidosis, which most often affects a person's lungs, but can also sometimes damage parts of their brain. 

Observed by Nick Medford, an expert in clinical neuropsychiatry at the Brighton and Sussex Medical School in the UK, doctors decided that the best treatment for the man's sarcoidosis was to remove his already damaged left amygdala, but the surgery left him with some rather odd side-effects. "Not only did he have a peculiar "stomach-lurching" aversion to music - which was particularly noticeable when he heard the song accompanying a certain TV advert - but he also discovered he was no longer afraid of spiders," reports Thompson.

Over time, the man found his strange aversion to music disappeared again, but he's remained unafraid of spiders, able to touch them and be close to them without feeling any fear. But his fear of public speaking has remained unchanged. It's not clear why one phobia was cured by the procedure over another, but Medford suspects it has something to do with our 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 realise it's just a stick," he told Thompson at 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."

Having published the findings in the journal Neurocase, Medford wants to continue testing how different types of fears are controlled by different regions of the brain. It's hoped that a better understanding of how fears are controlled by the brain will lead to new non-invasive procedures that can mitigate them, such as having a part of the brain stimulated so bad memories can be erased.

Source: New Scientist