Activities of the intralaryngeal muscles during electrically induced vocalization in decerebrate cats

Electromyograms were recorded from the intralaryngeal muscles (the posterior cricoarytenoid (PCA) and thyroarytenoid (TA) muscles) and the ventilatory muscles (the diaphragm (DA) and abdominal (RA) muscle) during electrically induced vocalization in precollicular postmammillary decerebrate cats. Electrical stimulation (rectangular pulses, 0.2 ms, 10-60 microA, 100 Hz, lasting 5-10 s) delivered to the rostral pons (Horsley-Clarke coordinates, A 1.0 to P 2.0, L or R 3.0 to 5.0, H -4.5 to -6.0) induced alternate inspiration and vocalization. The normal respiratory rhythm was reset to a new one and the intralaryngeal and ventilatory muscles were coordinately activated to produce vocalization. During the period of the electrical stimulation, preceding activity of PCA to DA and postinspiratory activity of DA, which were normally observed during quiet breathing, disappeared. These results suggested that the tonic electrical stimulation delivered to the rostral pons acted as a command signal to alter teh pattern generation of the ventilatory and laryngeal systems from quiet breathing to vocalization.