Effects of tracheostomy on electrically induced vocalization in decerebrate cats

Electrical stimulation delivered to the rostral pons induced well coordinated activity of the intralaryngeal muscles and the ventilatory muscles for vocalization in unanesthetized, decerebrate cats. The stimulation reset the normal respiratory rhythm and induced vocalization with a newly developed rhythm. Continuous opening of the tracheostomy decreased the breathing cycle during induced vocalization. Opening of the prepared tracheostomy during vocalization caused a sudden decrease in the subglottic pressure, but the expiration phase was not abruptly terminated. These findings suggested that vagal feedback from pulmonary stretch receptors plays a more significant role in the maintenance of the breathing cycle during electrically induced vocalization than the laryngeal feedback from the laryngeal mucosa.