Neural Control of Mastication: Ion-Channel Mechanisms in the Brainstem Central Pattern Generator.

Mastication is a fundamental rhythmic motor behavior controlled by a brainstem central pattern generator (CPG) located within the pontine and medullary reticular formations. Coordinated activation of jaw-opening and jaw-closing muscles is generated by this network and continuously refined through sensory feedback from periodontal mechanoreceptors and muscle spindles, together with descending inputs from the cortical masticatory area (CMA), basal ganglia, and cerebellum. Thus, mastication is regulated by distributed neural circuits rather than a single central locus. At the cellular level, the rhythmic activity of the masticatory CPG depends on the coordinated action of voltage-gated and ligand-gated ion channels. Recent electrophysiological and computational studies have identified candidate conductances that are proposed to underlie rhythm generation. Persistent sodium currents are proposed to facilitate burst initiation, whereas T-type calcium channels are thought to promote burst activation through post-inhibitory rebound. HCN channels may contribute to rhythmic timing, while calcium-activated potassium channels are thought to participate in burst termination. This review summarizes the hierarchical neural control of mastication and the biophysical mechanisms by which ion channels shape CPG rhythmogenesis. It also discusses the impact of channelopathies and neurodegenerative disorders on masticatory function, highlighting potential ion-channel-targeted therapeutic approaches for temporomandibular disorders, bruxism, and impaired mastication.