Previous Lecture Complete and continue  

  The Sense of Inch

Let's talk about itch.

In an early version of the course handout, I'd accidentally written itch four times! I think it's because it's the one sense that feels utterly compulsive.

Itch is a distinct sensor system from touch, but related since it has to do often with the skin.


From the dictionary:

(Definition from

From a physiological definition:

Itch (also known as pruritus) is a sensation that causes the desire or reflex to scratch.[1] Itch has resisted many attempts to classify it as any one type of sensory experience. Modern science has shown that itch has many similarities to pain, and while both are unpleasant sensory experiences, their behavioral response patterns are different. Pain creates a withdrawal reflex, whereas itch leads to a scratch reflex.[2] Unmyelinated nerve fibers for itch and pain both originate in the skin; however, information for them is conveyed centrally in two distinct systems that both use the same nerve bundle and spinothalamic tract.[3] (From wikipedia:


How did you experience itch?

Have you ever had an itch that you couldn't not scratch?

That urgency.. how you feel compelled... that sense of if you don't do scratch it, you're going to explode.

In what other ways do you use "an itch I couldn't scratch" as a metaphor for other things in your life?

What things on your life has caused itching? Bug bites? Mosquitos? Poison ivy? Poison oak?



"Joe was annoying twenty-four-seven with his know-it-all routine. He got under her skin like nobody else at the firm."

"She itched for some 73% chocolate, but didn't want to get off her couch."

"There was a place on my ankle that got to itching, but I dasn't scratch it; and then my ear begun to itch; and next my back, right between my shoulders. Seemed like I'd die if I couldn't scratch." -- The Adventures of Huckleberry Finn (Chap. 2) Mark Twain

From "Scientists Identify Neurons That Register Itch"

(From "Scientists Identify Neurons That Register Itch":


Consider your POV character.

What is their INTERNAL EXPERIENCE of itch?

What is their EXTERNAL EXPERIENCE of itch?


Share how your main character experiences itch.

Also, share your discoveries, ahas, and questions.