Figure 3: Schematic diagram of the behavioural experiment.
(a) Subjects needed to adapt to a −30° or 30° visuomotor rotation after experiencing the force channel trials (see below). (b) Throughout the experiment, the target direction was fixed to 90°. In the force channel trials, the actual hand-movement direction was also fixed to 90° using a virtual wall (force channel trial). In groups 1, 2 and 3, the cursor movement varied randomly in every trial, every two trials and every three trials, respectively. (c) Prediction of our model in test trials (each xt value is calculated by averaging across 100 simulations). In this simulation, xt in each force channel trial is forcibly set to 0. The PE can be predicted more reliably in groups 2 and 3 than in group 1, and the motor learning is predicted to be facilitated in groups 2 and 3 compared with group 1: learning speed is significantly higher in groups 2 and 3 than in group 1.
