Figure 1

(A) Action onset and its reliability to predict the relevant task variable: temporal error with respect to the moving target. The uncertainty in determining the planning of the action onset (hidden variable) is illustrated by the orange Gaussians, while the execution noise is denoted by the blue Gaussians centered at the actual action onset. Different variabilities in the planning of action onset or its execution are denoted by the type of line (dashed: lower noise; solid: higher noise). The prediction error is the difference between the planned (or predicted) and actual action onset. The top row illustrates a slow movement after action onset (longer duration until crossing the target) and the bottom row a fast movement. One would expect larger corrections when the execution noise of the actual action onset is lower (blue dashed curves) relative to the planning noise (solid orange curves). The relevance of the prediction error is expected to decay after action onset (green area), while the increasing relevance of the final temporal error for planning the next trial is denoted by the red area. (B) Illustration of two of the experimental tasks: arm movements (top) and eye movements (bottom).