The next time you irritate your family or friends by humming the same tune over and over and over, you can blame it on the pesky earworm that's slithered into your brain.

However, before your parents panic, be sure to explain to them that this earworm is not the wiggly kind, but a metaphor used by researchers to explain a phenomenon called musical itch or stuck song syndrome that happens when a tune attaches itself to the brain like a leach, and feeds off the memories, causing the same notes to repeat over and over.

Researchers at the University of Massachusetts, Dartmouth, did a study on the science behind this problem that happens to almost everybody in the world at some time or another. To test what is going on, they first isolated the auditory cortex - the region of the brain that perceives and stores all our auditory memories.

They then asked 15 people to create a customized play list with songs, lyrics or music that they knew well. After that, they took each individual and played him or her a list of songs, some off their play list, others, totally new. Ever so often, without any warning, they would hit the mute button.

Observing the brain activity using an MRI scanner, they noticed an interesting phenomenon - whenever the subject knew the song or the words were easy enough to guess, the auditory cortex filled in the missing part so well, that the person did not realize that the music had stopped and continued humming.

However, when they were unfamiliar with the song, they would wait in silence. Even after leaving the scanner, most people reported that the songs they knew, kept popping into their heads for a long time.

While researchers don't know why a particular song sticks to someone's mind it seems to happen largely either with songs that are catchy or where the lyrics keep repeating or, during particular times of the day - like first thing in the morning or last thing at night.

Also, it seems to happen more to women than men. Amongst the classic earworms identified were the theme song from Mission impossible and Who Let the Dogs Out by Baha Men.

So how do you treat an earworm? You could use an eraser - that is start humming another song - Be warned however, that this could turn into another parasite and haunt you! You could also pass it on to a friend or family member (fun!) or, simply let it go untreated - After all, it is just a 24-hour virus!

Are you prone to earworms - If so, be sure to let us know by adding your comments below.

sources: How Stuff Works.com, msnbc.com