Summary of the experimental protocol for saccade adaptation. Throughout the experiment the subject is seated in a dark room. (A) Open-loop trial: 1) During this trial the target turns on 2) as soon as the subject starts moving the eyes towards the target (red arrow) the target turns off. Open-loop trials were obtained before and after saccade adaptation paradigms. (B) Gain-decreasing saccade adaptation paradigm: 1) The target (T1) turns on, 2) as soon as the subject starts to move their eyes towards the target, it turns off. 3) Once the eyes reach the estimated location of T1, another target (T2) turns on, but 2.5 degrees closer to the previous position of the eyes, introducing an error signal. 4) As a result the subject makes a corrective saccade to T2. (C) Gain-increasing saccade adaptation paradigm: This is analogous to the gain-decreasing saccade adaptation paradigm. However, during steps 3 and 4, T2 appears 2.5 degrees farther away from the previous position of the eyes, inducing an error signal to make larger saccades.