Neuroscientists at the Johns Hopkins University School of
Medicine have discovered how the sense of touch is wired in the
skin and nervous system. The new findings, published Dec. 22 in
Cell, open new doors for understanding how the brain collects
and processes information from hairy skin. "You can deflect a
single hair on your arm and feel it, but how can you tell the
difference between a raindrop, a light breeze or a poke of a
stick?" says David Ginty, Ph.D., professor of neuroscience at
Johns Hopkins. "Touch is not yes or no; it's very rich, and now
we're starting to understand how all those inputs are
processed." Ginty and his colleagues study how the nervous
system develops and is wired. In trying to understand how touch-
responsive nerve cells develop, they set out to build new tools
that enable them to look at individual nerve cells. According to
Ginty, there are more than 20 broad classes of so-called
mechanosensory nerve cells in the skin — of which only six
account for light touch — that sense everyt