Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6263453 | Brain Research | 2014 | 9 Pages |
â¢We examined salivation controlled by two masticatory cerebral cortices in rats.â¢Salivation was evoked by stimulation of one masticatory area in the insular cortex.â¢The other masticatory cortex induced only jaw movements like lick solutions.â¢Two different masticatory cortices exist in terms of salivation in rats.
To evaluate the role of the masticatory area in the cerebral cortex in the masticatory-salivary reflex, we investigated submandibular salivary secretion, jaw-movement trajectory and electromyographic activity of the jaw-opener (digastric) and jaw-closer (masseter) muscles evoked by repetitive electrical stimulation of the cortical masticatory area in anesthetized rats. Rats have two cortical masticatory areas: the anterior area (A-area) in the orofacial motor cortex, and the posterior area (P-area) in the insular cortex. Our defined P-area extended more caudally than the previous reported one. P-area stimulation induced vigorous salivary secretion (about 20 µl/min) and rhythmical jaw movements (3-4 Hz) resembling masticatory movements. Salivary flow persisted even after minimizing jaw movements by curarization. A-area stimulation induced small and fast rhythmical jaw movements (6-8 Hz) resembling licking of solutions, but not salivary secretion. These findings suggest that P-area controls salivary secretion as well as mastication, and may be involved in the masticatory-salivary reflex.