Open-source joystick manipulandum for decision-making, reaching, and motor control studies in mice

Abstract

To make full use of optogenetic and molecular techniques in the study of motor control, rich behavioral paradigms for rodentsmust rise to the same level of sophistication and applicability. We describe the layout, construction, use and analysis of data from joystick-based reaching in ahead-fixed mouse. The step-by-step guide is designed for both experienced rodent motor labs and new groups looking to enter into this research space. Using this platform,mice learn to consistently perform large, easily-quantified reaches, including during a two-armed bandit probabilistic learning task.The metrics of performance (reach trajectory, amplitude, speed, duration, and inter-reach interval) can be used to quantify behavior or administer stimulation in closed loop with behavior. We provide a highly customizable, low costand reproducible open-source behavior training platform for studying motor control, decision making, and reaching reaction time. The development of this software and hardware platform enables behavioral work to complement recent advances in rodents, while remaining accessible to smaller institutions and labs, thus providing a high-throughput method to study unexploredfeatures of action selection, motivation, and value-based decisions.

Significance Statement We are realizing that the behavioral repertoire of mice is much richer than previously thought, including motor control and decision-making using reaches. Modern neuroscience is now capturing this richness, paired with new genetic tools, to understand fundamental neuroscience principles. Here, we provide an illustrated build guide, code, multiple use scenarios, and analytic tools to a low-cost, highly customizable mouse joystick. This tool will enable improved throughput, accessibility, and experimental design (e.g. spatiotemporal reach trajectories over lever presses) for labs wishing to study a range of reach-based experiments.