Fig. 6: Summary of RAm Nts neuron innervation and function.
From: A brainstem circuit for phonation and volume control in mice
RAm Nts neurons (red) innervate the trigeminal motor nucleus (MoV), which contains jaw opening motor neurons; the ventral respiratory column (VRC) and cervical spinal cord, which increase inspiratory (tidal) volume and expiratory time; Amb CT motor neurons, which adduct and tense the vocal folds; and the hypoglossal nucleus (nXII), which positions the tongue. RAm Nts neurons generate expiratory force through their indirect innervation of EO motor neurons in the spinal cord, possibly through a local interneuron (gray). All the above functions combine to produce sound (phonation). In addition to generating phonation, the RAm Nts neuronal activity level (red gradient triangle) determines the volume of the produced sound (black gradient triangle) by adjusting abdominal expiratory pressure via the EO muscle. RAm Nts neurons receive input from the midbrain periaqueductal gray and probably from other brain regions (not shown) to initiate phonation and adjust volume during diverse vocalizations.
