The effect of intrahypothalamic serotonin reinforcement on directional preference in rats.

Reinforcing properties of serotonin administration to the lateral hypothalamus were tested on the experimental model of the T-maze learning in 19 rats. The results did not definitely prove either positive or negative reinforcement produced by the central serotonergic stimulation, although the rats modified their behavior in the maze in the response to intrahypothalamic serotonin. It seems that the central serotonergic neurons do not play a decisive role in the mediation of the reinforcing phenomena but they may interact with the activity of some other reward neurons.