"A good scratch can cure an itch"

Interesting study:

That's why a new study published today in the journal Nature Neuroscience offers some hope of lasting relief. A group of neuroscientists led by Glenn Giesler at the University of Minnesota in Minneapolis hypothesized that the mechanism by which scratching relieves an itch takes place not along the nerve fibers of itchy skin, but deep within the central nervous system itself — specifically, in the spinothalamic tract (STT) neurons within the spinal cord, which transmit information about pain, temperature and touch to the brain.

Giesler theorizes that the itch sensation creates an excited state in the STT neurons that scratching somehow inhibits — as if our fingernails were somehow sending a message to spinal cord neurons to cool off. Scientists are still a long way from understanding the itch-scratch phenomenon, and while Giesler's study gives them a good place to start, neuroscientists caution that in humans, the mysteries of itching and scratching may go beyond the physiological: Emotional and psychological factors are also often at play, especially in cases of unexplained, unremitting itching or itching of phantom limbs. [Time]