FIGURE 1.

Experimental design. (A) Images of the four objects selected to represent different levels of required grasp force. (B) Task presentation and timing of the attempted grasp and object observation trials. (C) Object transport trial example. For this task, the name of one of the four objects was played at the start of the trial and the subject was then asked to attempt to use the virtual arm to grasp and transport the virtual object with the appropriate amount of force. Five position targets were used including a center target and four others approximately 20 cm above, below, left, and right of center.