3D-printed operant chambers for rats: Design, assembly, and innovations.

Ten years ago, we started a project at the National Autonomous University of Mexico with the purpose of building custom-made operant conditioning chambers that could be used in research and laboratory courses. The focus was to reduce the cost and improve the flexibility of operant chambers by integrating advances in electronics and manufacturing processes such as 3D printing and laser-cutting technologies. With these technologies we designed and built customizable and reliable operant chambers for rats in which responses can be recorded using levers or photocells. Reinforcement is delivered precisely using a pellet or a water dispenser and auditory and visual stimuli are presented with buzzers and LEDs. An Arduino microcontroller board connected to a PC running programs written in Visual Basic controls and records experimental events. The origins and latest improvements of the project are described and instructions to build one operant chamber are provided. Additionally, we describe a few examples of modifications of the design with the purpose of researching a wider range of behavioral phenomena. The designs and programs are open-source and open-distribution so they can be downloaded for free and can be modified freely by users to adapt to numerous experimental settings.