Scratching that itch

 
By HSC Staff Writer • Published: April 23rd, 2008
Category: Health in a Heartbeat
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Got an itch? Then scratch it! But have you ever wondered why you immediately scratch it… and why it feels oh-so-good when you do? So have scientists, who until now have… well… only scratched the surface about why relieving an itch feels so good.

A Wake Forest University study is the first to reveal what goes on in our brain when we scratch, and why a good scratch can produce relief.

Researchers used a soft brush to scratch thirteen healthy people on the lower leg. The leg was brushed on and off every thirty seconds for a total of five minutes. At the same time, researchers used magnetic resonance imaging to observe which areas of the brain were active during scratching.

Here’s what they found. While the people were being scratched, regions of the brain linked to unpleasant feelings and memories became less active. And during vigorous scratching, those brain areas became even more inactive.

Researchers believe scratching relieves an itch because it shuts down the part of the brain that finds an itch unpleasant. But they also found out why it’s hard to stop scratching once you start. Although scratching decreases activity in some parts of the brain, it increases activity in areas linked to pain and compulsive behavior.

Researchers are itching to learn more about how the brain reacts to scratching, in hopes of developing new treatments for people tormented by chronic itch, especially those with eczema [ECK-zuh-mah] and those on kidney dialysis.