Date of Award
Doctor of Philosophy
William H. Calhoun, James N. Liles, Harry M. B. Hurwitz
Many learning theorists have distinguished between autonomic responses which can be conditioned using classical conditioning procedures, and skeletal responses which can be conditioned using operant or instrumental conditioning procedures. In recent years this distinction has been challenged since such autonomic responses as changes in heart rate, GSRs, vasoconstriction and vasodilation, and changes in blood pressure have all been conditioned as operants.
The aim of this study was to investigate the possibility that both increases and decreases in heart rate could be conditioned in groups of curarized rats using an operant conditioning procedure with brain stimulation as the reinforcement for the heart rate changes. Curarized rats were used in order to markedly reduce the possibility of skeletal mediation of the heart rate changes which were conditioned. Brain stimulation was used since it has been found to have powerful reinforcing effects for more typical operant responses. A feedback stimulus was presented to the rats during the curare conditioning sessions whenever they were emitting criterion heart rates, i.e. heart rates which if sustained for a fixed number of beats would be followed by the brain stimulation. Two groups of six rats were used, one group being reinforced for heart rate increases, and one for decreases. All rats were given four curare conditioning sessions during which heart rate changes were reinforced.
During the first curare conditioning session no evidence of operant conditioning of heart rate changes was found. On the three later conditioning sessions significant differences were found in the heart rates of the two groups, with the group reinforced for heart rate increases showing the higher heart rate. There was also some evidence of an extinction effect during the later curare sessions in that the heart rates of the two groups which diverged during conditioning, tended to converge during extinction. The results of this experiment show that changes in heart rate can be conditioned in curarized rats using an operant conditioning procedure with brain stimulation as the reinforcement for the heart rate changes.
In a second experiment three rats were used in an attempt to first condition a heart rate change in one direction, and then to reinforce heart rate changes in the opposite direction. Although the three rats showed good acquisition of the initial heart rate change none of them showed any evidence of acquisition of the heart rate change in the opposite direction. The results from these three rats suggest that heart rate reversals will only be conditioned with great difficulty.
Hothersall, David, "Operant Conditioning of Heart Rate Changes in Curarized Rats with Brain Stimulation Reinforcement. " PhD diss., University of Tennessee, 1968.