CARDIAC CONDITIONING IN THE RAT - UNITED-STATES INTENSITY FUNCTION AND RESPONSE CONSTANCY THEORY

The classically conditioned cardiac response to electric shock was examined in five groups of 10 rats each. Twenty trials were presented each day for 10 days with either a 1 mA, 2 mA, 3 mA, 4 mA, or 5 mA subcutaneous shock as the unconditioned stimulus (US). Data were evaluated with reference to a general theory of autonomic activity termed Response Constancy theory. A mathematical derivative of the theory is a significant negative correlation between prestimulus levels and change scores, i.e. the Law of Initial Values. The theory predicts that degree of control exerted by a stimulus is reflected by the ability of the stimulus to produce a particular level of activity. Decreasing variability of conditioned heart rate was monotonically related to US intensity throughout, and negative correlations between prestimulus levels and change scores were observed in all groups. Magnitude of decelerative change was an inverted U‐shaped function of US intensity in acquisition, and a monotonic function of US intensity at asymptote. Copyright © 1979, Wiley Blackwell. All rights reserved