A comparison of the effects of amphetamine on fixed interval performance maintained by electrical stimulation of the brain versus food reinforcement

Rats with implanted unilateral hypothalamic bipolar electrodes were trained to bar press for both electrical stimulation of the brain (ESB) and food on a fixed interval (FI) 1-min schedule of reinforcement. A comparison in the same animals was made of the disruptive effects of d-amphetamine on FI performance maintained by these two reinforcers. Overall, FI remained more intact under the influence of amphetamine with ESB rather than with food reinforcement. The feasibility of using more complex schedules of reinforcement to study the effects of drugs on self-stimulation was demonstrated.