A comprehensive, affordable, open-source hardware-software solution for flexible implementation of complex behaviors in head-fixed mice.

Experiments that take advantage of head fixed behavioral tasks have been a staple of systems neuroscience research for half a century. More recently, rodents came to the forefront of these efforts, primarily due to the rich experimental possibilities afforded by modern genetic tools. There is however a considerable barrier to entering this field, requiring expertise in engineering, hardware- and software development, and significant time- and financial commitment. Here, we present a comprehensive, open-source hardware and software solution to implement a Head-fixed Environment for Rodent Behaviors (HERBs). Our solution provides access to three frequently used experimental frameworks (two-alternative forced choice, go-nogo, or passive sensory stimulus presentation) in a single package. The required hardware can be built at a relatively low cost compared to commercially available solutions, from off-the-shelf components. Our graphical user interface (GUI) based software provides great experimental flexibility and requires no programming experience for either installation or use. Furthermore, HERBs takes advantage of motorized components that allow the precise, temporal separation of behavioral phases (stimulus presentation, delays, response window and reward). Overall, we present a solution that will allow laboratories to join the growing community of systems neuroscience research at a substantially lower cost of entry. Significance statement In the past two decades, head fixed rodent preparations have become an invaluable tool in systems neuroscience. Still, setting up sensory perception or complex behavioral experiments remains an arduous task, requiring expertise in hardware- and software development, as well as significant time and financial investment. Here, we present a comprehensive, low-cost package to utilize a Head fixed Environment for Rodent Behaviors (HERBs). Our solution is complete with a flexible graphical user interface and can be built from mostly off-the-shelf components and operated by experimenters without any programming knowledge.