Itch-scratching can temporarily alter brain activity in distinctive ways, increasing activity in some areas while decreasing it in others, thus making people feel relaxed, said a study by Wake Forest University, North Carolina, in the Journal of Investigative Dermatology Friday.
The researchers used a technology known as functional magnetic resonance imaging to see what is goging on in the brain when a person is scratched.
They scratched 13 healthy volunteers with a soft brush on the lower leg for 30 seconds with a pause for 30 seconds, which would last five minutes total.
They found that scratching reduced activity in the anterior cingulate cortex and the posterior cingulate cortex -- two areas linked with pain aversion and memory, and the more intensely a participant was scratched, the less activity in these areas of the brain. When participants reported the most intense sensation from scratching, deactivation in the anterior cingulate cortex reached its highest level.
"It's possible that scratching may suppress the emotional components of itch and bring about relief," said Gil Yosipovitch, a dermatologist at Wake Forest University Baptist Medical Center
However, the researchers acknowledged the limitation because people were not scratching in response to an actual itch.
But they said their findings may help treat people tormented by chronic itch, including people with eczema and many kidney dialysis patients.
(Agencies via Xinhua News Agency February 1, 2008)