Prism adaptation
BehavioralPAT uses wedged prism lenses to displace the entire visual field horizontally to the left or right (depending on the orientation of the base of the prism). The left-base prism lenses (thicker on the left) shift the entire visual field to the right. The result is a curving reaching trajectory, aiming toward the image location (right to the actual location) and then corrected toward the actual location. After several reaching movement, the coordinates of motor and visual systems are aligned, which in other words, is that the motor output adapts to the visual input, and thus the reaching trajectory is straight ahead to the object. This visually-guided goal-oriented movement is essential in PAT.