Respiratory gating of activity in the avian vocal control system

Electrical stimulation of brain nuclei within the vocal control pathway of budgerigals ( Melopsittacus undulatus) or zebra finches ( Poephila guttata) evoked neural activity in the hypoglossal nerves innervating the vocal organ, the syrinx. This activity was gated within the hypoglossal motor nucleus such that stimulation recruited more hypoglossal motor neurons to fire during expiration than during inspiration. This respiratory gating mechanism represents a novel solution to the problem of shared control of motor neurons during different behaviors, and may contribute to the patterning of neural activity during song production.