Abstract
1. Reflex inhibition of cold shivering due to mechanical pressure applied on the face on the rabbit and its primary afferent pathway in the central nervous system was studied to clarify the mechanism of the “skin pressure reflex.”
2. Mechanical pressure on the eye-ball and the ear-root was greatly effective in inhibiting cold shivering.
3. The spinal trigeminal tract is the afferent pathway of the reflex inhibition of shivering by pressure on the face, that was proved by the tractotomy of the trigeminal nerve in the spinal cord.
4. The trigeminal fibers entering directly to the main sensory nucleus is not associated with the reflex inhibition. Small fibers of the spinal trigeminal tract, considered as GII or GIII fibers from the result parameter of electrical stimulation of the tract, might play an important role in conducting the impulses evoked by pressure applied to the face.
5. Phylogenetical aspects of the spinal cord and the anatomical, functional characteristics of the peripheral nerve were discussed in relation to the mechanism of the “skin pressure reflex.”
