HEART RATE CONDITIONING IN THE CAT AND ITS RELATIONSHIP TO OTHER PHYSIOLOGICAL RESPONSES

Twenty cats were classically conditioned using electric shock as the unconditional stimulus (US). A 1000 cps tone served as the reinforced conditional stimulus (CS+) and a 500 cps tone as the non-reinforced conditional stimulus (CS–). The CS–US interval was 10 seconds. Data collected show a heart rate deceleration to the CS+ which is accompanied by a drop in blood pressure, respiratory apnea, a negative baseline shift of the galvanic skin potential (GSP), pupillary dilatation, a decrease of the electromyographic (EMG) activity of the muscles of the shocked foreleg, and a low voltage fast pattern of the electroencephalographic (EEG) activity of the sigmoid gyrus of the cerebral cortex and olfactory bulb. The heart rate deceleration is present after muscle paralysis with succinyl choline and it is blocked by atropine. It is presumed to be of vagal origin. Difference in CS+ and US responsivity is discussed.