Figure 2:

Path Integration Toward an Unseen Target in Virtual Reality - Teaching Non-Human Primates How to Report. (A) The animal has linear and angular velocity control via a joystick, allowing it to navigate and explore a two-dimensional space made up of a target (the firefly - black disk) and triangular elements that are presented only briefly and thus serving as optic flow. (B) Example trial where the monkey navigates straight to the target and is rewarded if it stops within a reward zone (reward zone is never explicitly shown to the animals). (C) A collection of example trajectories.