Diaphragmatic and abdominal muscle activity during coughing in the decerebrate cat.

We studied electrical activity of the phrenic and abdominal nerves and from the diaphragm and abdominal muscles during coughing elicited by stimulation of the superior laryngeal nerves (SLN) in decerebrate spontaneously breathing cats. This activity was compared with that observed after partial and complete paralysis. During coughing, the duration, rate of rise, and amplitude of inspiratory discharge increased concomitantly with activity of the rectus abdominis and external, but not internal, oblique muscle. After end-inspiration, the abdominal muscles discharged with one or more bursts. Similar patterns of activity were observed in phrenic and abdominal nerves during SLN-induced coughing, first in spontaneously breathing and then in paralyzed, ventilated cats. The paralyzed, ventilated decerebrate cat provides a powerful experimental model for studying coughing.