Open-Source Joystick Manipulandum for Decision-Making, Reaching, and Motor Control Studies in Mice

Training and performance of specialized reaching tasks. A, The mouse joystick enables (1) a basic center-out task (all directions rewarded, dashed ring = reward amplitude threshold), (2) variable amplitude reaching wherein the reward amplitude can be changed within the session, (3) a reaction time task with a go-cue light, and (4) a bidirectional two-armed bandit task to assess decision-making, among other possibilities. In this case, reaches in different directions carry different reward probabilities. B, To demonstrate the ability to make discrete reaches in two directions, we demonstrate an x-y joystick position trace over a 30 min, two-armed bandit task session wherein the high probability rewarded direction changed with throughout the task. The solid black circle denotes initial training threshold for rewarded reaches at 0.35 cm, and dashed circle representing expert level threshold of 0.9 cm. C, Mean number of rewarded reaches (top) and reward threshold amplitude for each session performed by light early (green), light late (blue), and control (black) groups. D, Average of median reaction times for each session during light early and light late groups, aligned to cued light introduction session.