Operant discriminative conditioning of vertical eye movements in the midpontine pretrigeminal cat

Abstract

In the acute midpontine pretrigeminal cat, either upward or downward eye movements above a certain preset amplitude were reinforced by electrical stimulation of the lateral hypothalamic (LHT) reward area, which did not induce a significant eye movement by itself. During the course of the reinforcement procedure, eye movements greatly increased. In a yoked control test where LHT stimulation was delivered to a cat, independently of its own eye movements, no significant enhancement of the eye movements was observed. However, when reinforcement was given contigently on each large eye movement, eye movement rat became much higher. When cats were trained for an operant discrimination between an S + (light-off or light-on) and an S − (light-on or light-off), 5 cats acquired clearly differential responses to the S + and S −. They also learned a discrimination reversal. Furthermore, removal of the visual cue eliminated differential responses during the reinforcement and nonreinforecement periods. These data strongly suggest that, in this preparation, a real learning process in the form of a visual discrimination is maintained and an operant conditioning of eye movements with hypothalamic stimulation was achieved without feedback from the peripheral nerves or caudal central nervous system.