Oxygen consumption and ambulation during operant conditioning of heart rate increases and decreases in rats.

Abstract

ABSTRACTUsing a shock‐avoidance procedure, large discriminated increases and decreases in mean heart rate (HR) were conditioned respectively in two groups of free‐moving rats. Accompanying the conditioned HR responses were equally significant variations in Oxygen Consumption and Ambulation indicating a nonspecific effect of the experimental contingencies. Ambulation and Oxygen Consumption were found to be correlated in some but not all experimental conditions. Thus, partial indices of somatomotor activity may not provide an adequate reflection of variations in general activity (energy consumption) and therefore may not be employed to draw meaningful conclusions regarding the integration of cardiac and somatomotor processes. Discriminated HR responses were acquired more rapidly by subjects in the Increase condition than by subjects in the Decrease condition. However, the latencies of the discriminated HR changes were considerably longer for the Increase than for the Decrease subjects. An unexpected result was that 5 of the 6 Decrease subjects developed profound bradycardic arrhythmias. These arrhythmias were under strong stimulus control and were exhibited only during a stimulus (SD) signalling that the reinforcement contingencies were in effect.