The effect of train duration of rewarding stimulation on food self-deprivation

In order to assess the effect of changes in brain-stimulation reward (BSR) on food intake, train duration of BSR was manipulated during food/BSR competition periods. Train duration, rather than intensity, was used in order to hold the area of stimulation about the electrode tip constant. Train duration had a significant effect on food intake, with longer durations decreasing intake. Increases in food deprivation increased feeding during food/BSR competition, and the tendency for subjects to self-deprive was reduced over the 4 weeks of successive competition testing. Further analyses of the data revealed that stimulation on-time (defined as the product of leverpresses and train duration) was a better predictor of food intake than was leverpressing rate. The results are interpreted as supporting the hypothesis that choices for food or BSR during competition reflect the relative reward value of the alternatives.