Nearly all species of spiders are venomous even if they are not dangerous to humans. REUTERS

It was by sheer chance a surgery aimed at a different health condition totally cured a man of his phobia for spiders.

The man with arachnophobia, who took trouble to annihilate spiders that came his way, turned into one who now finds the insect fascinating and can even touch them.

When doctors noticed a rare condition causing damage to the man's lungs, skin and brain they had decided to remove a part of the brain, the left amygdala, an area in the temporal lobe which is the seat of emotions.

Following the surgery, the man reported two distinct changes – one was a deep aversion to music and the other, a loss of his earlier fear of spiders.

While the music aversion slowly waned, arachnophobia never returned, reports New Scientist. It was however not a case where he totally lost fear of everything.

According to his doctor Nick Medford at the Brighton and Sussex Medical School, UK, neural pathways related to the panic-type fear response were eliminated while parts of the amygdala responsible for generalised fear remained intact.

Temporal lobe surgery for severe epilepsy is common, but the region being too deep in the brain doctors have not been able to use non-invasive techniques to cure people of phobias.

Evolutionary psychology views the fear of spiders as a basic survival instinct given that nearly all species of spiders are venomous, even if not dangerous. But an opposing view looks at arachnophobia as a cultural, rather than genetic trait