At 20:32 3-02-95 GMT, Brad Wyble wrote:
>>SOunds somewhat similar to an effect that can be observed using
>vibration and muscle spindles. If you vibrate the bicep while the arm
>is upright and partially curled (about 60 deg from horizontal) and the
>subjects eyes are closed, the sensation that the arm is slowly curling
>more will be felt, causing the subject to extend the arm in
>compensation. The vibration stimulates the muscle spindles(I
>think...its been a while), causing gamma motor neurons to fire. This
>causes the illusion that your muscle is contracting. (I may have it bacwards)
>>>In any case, could sensory neurons in the gums be reacting to the
>vibration similarly? Does the itch happen regardless of what part of
>your mouth you're brushing? And I also wonder how the frequency of
>vibration affects the itch.
>> -Brad W.
There are no neurons in the gums, only nerves and sensory cells.
A vibrating toothbrush will certainly stimulate sensory structures, e.g.
Pacini-like cells, in the gums.
Another possibility is direct mechanical stimulation of the nerve.
When you apply light mechanical stimulation to the ulnar nerve at the
olecranon you will experience an itching-like feeling in the little finger.
Isn't that the same phenomenon?
Nerves can easily be excited by mechanical stimuli over bony structures, e.g
where the nerve leaves the skull on it's way to the oral tissues.
Jan Nauta, Groningen, the Netherlands
TCMA, Traditional Chinese Medicine Association
