Operant conditioning of pontine gigantocellular units

Abstract

In order to investigate the behavioral role of pontine gigantocellular field (FTG) units, we have operantly reinforced discharge in these cells in unrestrained cats using lateral hypothalamic stimulation as the reinforcing stimulus. Cats readily learned to increase discharge rate in reinforced FTG cells relative to simultaneously recorded, non-reinforced control cells. Increased FTG discharge was associated with elevated levels of motor activity and often with stereotyped movements. Our results are compatible with the hypothesis that FTG unit discharge is related to specific movements.

FIG. 1.

Method of operant conditioning of FTG cells. Upper trace: amplified unit output. Middle trace: integration of unit activity. Bottom trace: LH stimulation record (400 msec).

FIG. 2.

Unit discharge of a reinforced FTG cell. Each point represents 2 minutes. B=baseline (no reinforcement) periods; R=reinforcement periods. The cat was presented with a discriminative stimulus signaling reinforcement periods. Note increased discharge during reinforcement and successive extinction curves in baseline periods.

FIG. 3.

Unit discharge of a reinforced FTG cell and a control FTG cell. Each point=2 min. B=baseline periods. R=reinforcement periods. Note higher discharge of reinforced cell in the final 10 min of reinforcement (R4).