ACTIVITIES OF THE INTRALARYNGEAL MUSCLES DURING ELECTRICALLY-INDUCED VOCALIZATION IN DECEREBRATE CATS

Electromyograms were recorded from the intralaryngeal muscles (the pos terior cricoarytenoid (PCA) and thyroarytenoid (TA) muscles) and the v entilatory muscles (the diaphragm (DA) and abdominal (RA) muscle) duri ng electrically induced vocalization in precollicular postmammillary d ecerebrate cats. Electrical stimulation (rectangular pulses, 0.2 ms, 1 0-60 muA, 100 Hz, lasting 5-10 s) delivered to the rostral pons (Horsl ey-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 respira tory rhythm was reset to a new one and the intralaryngeal and ventilat ory muscles were coordinately activated to produce vocalization. Durin g 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 the pattern generation of the ventilatory and laryngeal systems from quiet breathing to vocalization.