Growling component of vocalization as a quantitative index of carbachol-induced emotional-defensive response in cats.

Vocalization and eye movements during emotional-defensive response evoked by unilateral intrahypothalamic carbachol injections (10 micrograms) were quantitatively determined. The growling episodes duration paralleled the development and the subsiding of the defensive behavior, while the changes of eye movements indicated rather a general arousal than the course of agonistic attitude. The growling component can be treated as (i) a specific form of vocalization for emotional-defensive response, (ii) quantitative intensity index of the response, and (iii) a value reflecting the dynamics and the time-course of the emotional state, unlike the hissing component which is inappropriate for quantitative determination. The results enable to treat the carbachol-induced response as a model for quantitative investigations on emotional-defensive states in cats. The vocalization changes compared with cardiovascular changes are discussed in terms of their usefulness in measurements of aversive emotional responses.