Influence of cerebral cortex stimulation upon cough-like spasmodic expiratory response (SER) and cough in the cat

In 27 pentobarbitalized cats, the influence of electrical stimulation of the cerebral cortex upon the spasmodic expiratory response (SER) was studied and compared with cortical influences on coughing induced by stimulation of the superior laryngeal nerve (sup. laryngeal N.). This cortical influence was evoked by electrical stimulation of the cortical nucleus of amygdala (Aco), and was very similar to coughing accompanying changes in emotional behavior and was depressed more effectively by psychotropics than by centrally acting antitussives like codeine. When anterior cingulate gyrus (ant. cingulate G.) or orbital gyrus (orbital G.) were stimulated simultaneously with Aco or sup. laryngeal N., weak stimulation was sufficient to inhibit SER, while stronger stimuli were needed for the suppression of cough. If the same cortical regions were stimulated after initiation of SER or cough, SER was markedly suppressed but cough little affected. Production of SER was facilitated by simultaneous stimulation of the piriform lobe (piriform L.) or olfactory tract (olfactory T.), whereas cough production was facilitated by simultaneous stimulation of the suprasylvian gyrus. These results suggest that SER and coughing are differently controlled by the cerebral cortex, and that SER is modulated by the limbic cortex, in particular, by ant. cingulate G., orbital G. and piriform L. The mechanism of modulation for SER is discussed.