February 1, 2008

Why Does It Feel So Good To Scratch

Would you have ever guessed that scratching an itch actually shuts off areas of your brain?

A dermatologist at Wake Forest University Baptist Medical Center in Winston-Salem, North Carolina, Dr. Gil Yosipovitch, recently conducted a study that provides evidence of how scratching can relieve an itch.

This study, paid for by the National Institutes of Health, digs deeper than previous studies. Tests have shown prior to this research that pain inhibits the need to itch. Yosipovitch felt the need to search deeper; he wanted to see what occurs in the brain when someone is scratched.

The device used for this study scratched 13 healthy people in 30 second intervals for five minutes with a soft brush on the lower leg. The research team used functional magnetic resonance imaging to decipher which areas of the brain were activated by the scratching.

They found that activity was increased in the secondary somatosensory cortex, a center for pain, as well as the section of the brain linked with compulsive behavior, the prefrontal cortex. Yosipovitch thinks this could explain why there is a compulsion to continue scratching once scratching has begun.

Certain areas had the complete opposite reaction; activity was seriously reduced in the anterior and posterior cingulated cortices. These two areas are linked with memory and pain aversion, and the more a person was scratched, the less activity showed in these areas.

Yosipovitch stated, ""It's possible that scratching may suppress the emotional components of itch and bring about relief."

The study had limits, such as the fact that people were not scratching themselves, and the scratching was not a response to a real itch.

The understanding that the study brings may provide a future solution to people who have eczema or other forms of chronic itch.  


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Wake Forest University Baptist Medical Center