The Effects of CS Habituation and Duration of the Directional Modification of the Cardiac Response in the Guinea Pig (Cavia procellus)

The present experiment examined the effects of CS habituation and two different levels of CS duration (60 versus 6 sec) on the directional modification of the conditioned cardiac response in the guinea pig. The results indicated that the only reaction to the CS, regardless of prior habituation or CS duration, was a decelerative conditioned HR response. However, habituation to a CS prior to classical aversive conditioning was found to attenuate the magnitude of the bradycardia CR that developed. The bradycardia CR was discussed in terms of being a cardiac component of the orienting response