Why does our skin gets itchy when we make contact with something that’s shaking, like a bus seat or a massage chair?
In: Biology
There are several types of nerves in your skin that detect “touch”. Different types of nerves are specialized for things like sharp objects, texture, motion, vibration, and pain/itch/temperature.
Pacinian corpuscles are the ones that are specialized to sense vibration. Each of these nerve endings have a rather large zone of sensation, so that’s why it’s difficult to localize precisely where on the skin is vibrating. You just generally feel an area of vibration. These pacinian corpuscles are deeper in the skin compared to “free nerve endings”, which detect itch. Thus, activation of the pacinian corpuscles almost always involves activation of free nerve endings as well.
Your brain is able to process the incoming inputs (via the thalamus, cortex, and other midbrain areas) and determine that it is not painful. Therefore, the input from the free nerve endings is interpreted as itch or slight discomfort.
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