Motor control of crystallized song is modified by sensory feedback

Song production requires precisely coordinated activity in the respiratory and syringcal (vocal organ) muscles. Crystallized adult song is characterized by acoustic and motor stereotypy which does not require auditory feedback, suggesting it is represented by fixed central motor programs. To determine if this adult motor pattern is modulated by sensory feedback, we briefly increased the respiratory pressure by injecting short (10 - 30 ms) puffs of air through a cannula into a cranial thoracic air sac of singing, adult male cardinals (Cardinalis cardinalis), while monitoring air sac pressure, the rate of airflow through each bronchus and the electromyogram (EMG) of abdominal expiratory muscles.