Fig. 5.

Reaching accuracy in unconstrained tasks.A, Crosses represent movement end points for each instruction direction in the unconstrained rotation task (for additional details, see the legend for Fig. 3A).Dashed vertical orvertical-oblique lines that are drawn equidistant from the origin represent partial vectors on which “correct” end points could lie. B, Relationship between achieved and instructed direction in the unconstrained rotation task is shown. Symbols and features are described in Figure 3B except for the thin solid line that corresponds to the regression obtained from the constrained rotation task and the thick solid line that corresponds to the regression obtained from the unconstrained rotation task. C, Crosses represent movement end points for each instruction distance in the unconstrained extension task. Dashed semicircles partially represent the locations where correct end points could lie. D, Relationship between achieved and instructed distance in the unconstrained extension task is shown. Lines are described in B.