Sensitivity of anterior digastric and intrinsic tongue muscle reflexes to electrical stimulation of various areas in the rat palate

Abstract

The relationship between the sensitivity of various palatal sites to electrical stimulation and threshold reflex activity of the anterior digastric and the intrinsic tongue muscles was studied in decerebrated rats. For the anterior digastric muscle, threshold levels increased in antero-posterior direction; the papilla incisiva and the medial sites on the first antemolar ruga showed the lowest thresholds; medial test spots had lower thresholds than lateral ones. For the intrinsic tongue muscles the papilla incisiva had the lowest thresholds; otherwise thresholds decreased towards postmolar sites; but, in the posterior part of the postmolar region thresholds were markedly raised. Inter-muscle comparison of thresholds showed that in the antemolar region and the most posterior area the digastric had the lowest thresholds. In the intermolar field, no differences between digastric and tongue thresholds were found.