How the brainstem controls orofacial behaviors comprised of rhythmic actions

• Mammalian face and mouth contain sophisticated motor plants that produce diverse orofacial behaviors.
• Brainstem contains key neural circuits that drive and coordinate different cranial motoneurons to produce various orofacial actions.
• All orofacial actions are coordinated with breathing.
• Three major neural computational mechanisms coordinating orofacial actions are discussed.

Mammals perform a multitude of well-coordinated orofacial behaviors such as breathing, sniffing, chewing, licking, swallowing, vocalizing, and in rodents, whisking. The coordination of these actions must occur without fault to prevent fatal blockages of the airway. Deciphering the neuronal circuitry that controls even a single action requires understanding the integration of sensory feedback and executive commands. A far greater challenge is to understand the coordination of multiple actions. Here, we focus on brainstem circuits that drive rhythmic orofacial actions. We discuss three neural computational mechanisms that may enable circuits for different actions to operate without interfering with each other. We conclude with proposed experimental programs for delineating the neural control principles that have evolved to coordinate orofacial behaviors.