An inexpensive new device to provide random rewards for behavioral studies.

Behavior modification in rats often involves controlling the frequency of providing food rewards. This is accomplished with computer-controlled devices or equipment purchased specifically for this purpose. Investigators currently choose from a few commercially available models, but each has its disadvantages or limitations, including a high cost (about US$1000). Computer-controlled devices can also be expensive and need a dedicated machine and software packages to perform the tasks. We designed a custom-built device to reward an action randomly from 1 out of 10 times to 10 out of 10 times. The device can be manufactured easily and inexpensively (about US$150). It has been in use for several months in our laboratories with no malfunctions.