An open source device for operant licking in rats

Increasingly complex data sets are needed to fully understand the complexity in behavior. Credit card sized single-board computers with multi-core CPUs are an attractive platform for designing devices capable of collecting multi-dimensional behavioral data. To demonstrate this idea, we created an easy to-use device for operant licking experiments and another device that records environmental variables. These systems collect data obtained from multiple input devices (e.g., radio frequency identification tag readers, touch and motion sensors, environmental sensors) and activate output devices (e.g., LED lights, syringe pumps) as needed. Data gathered from these devices can be automatically transferred to a remote server via a wireless network. We tested the operant device by training rats to obtain either sucrose or water under the control of a fixed ratio, a variable ratio, or a progressive ratio reinforcement schedule. The lick data demonstrated that the device has sufficient precision and time resolution to record the fast licking behavior of rats. Data from the environment monitoring device also showed reliable measurements. By providing the code and 3D design under an open source license, we believe these examples will stimulate innovation in behavioral studies. http://github.com/chen42/openbehavior.