When we drag our nails across a chalkboard, it's not pleasant. But dragging our nails across our skin often provides us nothing but relief from a prickly, tickly sensation know as The Itch. Just what is it about scratching an itch that causes the itchy sensation to go away? New research out this week in the journal Nature Neuroscience provides an answer. And we're itchin' to tell you about it: Glenn Geisler, one of the scientists involved with the work, joins The Takeaway with more.