Optimization of Medial Forebrain Bundle Stimulation Parameters for Operant Conditioning of Rats.

Background: The medial forebrain bundle (MFB) is involved in the integration of pleasure and reward. Previous studies have used various stimulation parameters for operant conditioning, though the effectiveness of these parameters has not been systematically studied. Objectives: The purpose of the present study was to investigate the optimal MFB stimulation parameters for controlling the conditioned behavior of rats. Methods: We evaluated four factors, including intensity, frequency, pulse duration, and train duration, to determine the effect of each on lever pressure applied by animals. We further compared burst and tonic stimulation in terms of learning and performance abilities. Results: The number of lever presses increased with each factor. Animals in the burst stimulation group exhibited more lever presses. Furthermore, the average speed in the boxed plus maze among burst stimulation group subjects was higher. Conclusion: We determined the optimal parameters for movement control of animals in operant conditioning and locomotor tasks by adjusting various electrical stimulation parameters. Our results reveal that a burst stimulation is more effective than a tonic stimulation for increasing the moving speed and number of lever presses. The use of this stimulation technique also allowed us to minimize the training required to control animal behavior. (C) 2019 S. Karger AG, Basel