Figure 4.

Profiles of (A) a normal and (B) a corrected spatial reach path during binocular movements toward the same “near, midline” target (filled circle) in (A) a left-handed control subject aged 7.25 years and (B) a right-handed stereo nil patient aged 7.33 years. The origin (0) of both movements on the x-axis corresponds to the starting hand positions; solid traces show the reach paths collapsed into lateral and forward directions and terminating just short of the target (as they were recorded from the marker on the wrist). In (A) the movement of the left hand follows a typical, slightly curved trajectory in a leftward (x-axis, -ve) lateral direction, but in (B) the trajectory is not a rightward mirror-image. Instead, the patient initially moved slightly rightward (open arrow), but misdirected his reach toward the midline well short of the target's location, necessitating a subsequent trajectory correction (filled arrow)—defined as a spatial path error—in order to acquire it.