An automatic food delivery system for operant training of mice

We describe an adjustable food delivery system that cuts and delivers calibrated pieces of spaghetti to be used as reinforcers to train mice in an appetitive bar-pressing task. The food delivery is computer-controlled. Uneaten reinforcers are detected and removed automatically. One main advantage of this system is the ability to adjust reinforcer size to as small as 3 mg. A second advantage is that small reinforcers effectively prevent the rapid satiation usually observed with commercial products designed for rats, and allow for the expression of high behavioral output. Finally, the use of these dustless reinforcers drastically reduces the incidence of blockage, a common occurrence with commercial products using pellets.