Background:
We
hardly think about our sense of touch until something goes wrong—trying
to find a small object with gloves on or waiting for dental anesthetic to wear
off so our faces don’t feel “dead” are a few things that make our awareness of
touch noticeable. What a relief when things are back to normal! Just how does
the skin let the brain know what it is touching? You’ve noticed that when you
want to find out whether something is smooth or rough, you run your fingertips
over it, rather than the palm of your hand or your elbow. And you may have
noticed that you can feel a tiny fragment of a bone in your mouth, but you
wouldn’t have noticed it at all if you had stepped on it with your bare foot.
What does it mean when part of your body is “better” at getting touch
information?
Goal: In
this activity you will measure the distance you are able to detect “touch” on
the forehead, cheek, forearm, palm of hand, tip of thumb, tip of index finger
and back of lower leg. The closer together you can determine a pin prick, the
more concentrated the neurons in that region of the body are.