[Response properties of single sensory units innervating human temporomandibular joint]

The purpose of this study was to examine the response patterns of single sensory units innervating the human temporomandibular joint to the displacements of the mandibular head. 13 single sensory units were recorded from the auriculotemporal nerves of five adult subjects by the method of microneurography and the response patterns were analyzed. The results obtained were as follows: (1) The response patterns of the same unit to the directions of the mandibular movements were classified as Slowly Adapting Type and Fast Adapting Type according to the characteristics of their adaptation. (2) The threshold value of the Fast Adapting Type was higher than that of the Slowly Adapting Type. (3) Increasing the rate of the mandibular opening movements in the initial stage, the firing frequency of the units increased in the response pattern of the Slowly Adapting Type. It was concluded that the sensation in the directions of the displacements of the mandibular head can be induced by the response patterns of the impulses in the nerve fibers innervating the temporomandibular joint.