[Jaw and perioral reflexes elicited by tooth tapping in the cat]

The reflex responses elicited by tapping the maxillary canine were studied in 12 adult cats anesthetized with alpha-chloralose. Short (4-8 msec) and long (14-22 msec) latency responses were recorded from both efferent nerves innervating a digastric muscle and an inferior portion of perioral muscles. These two responses were also observed from a single fiber teased from the efferent nerve as two successive groups of spike discharges. The long-latency responses from the digastric and the perioral muscle were both elicited by a light tooth tapping and disappeared at about the same time following infiltration of local anesthetic over the tap-stimulated tooth root or following inhalation of ether narcosis. The long-latency responses from the above muscles may be, therefore, elicited by the same sensory information of the periodontal afferent, and have a common reflex center.