Fig. 1.

Hand positions at which the hand-blink reflex (HBR) was recorded in the 6 experiments. The HBR was elicited by electrical stimulation of the right median nerve at the wrist. In experiment 1, the hand was placed 4, 20, 40, and 60 cm from the face along the sagittal plane at a downward angle of 15° from the eye (Sambo and Iannetti 2013). In experiment 2, the “front” position was the same as the nearest position of experiment 1, and the “rotated side” position was the same as “front” but with the head rotated 90° to the left (Sambo et al. 2012b). In experiment 3, the hand was placed in 5 positions along a coronal plane 4 cm in front of the face at eye height. In experiment 4, the hand was similarly placed at 5 positions on the same coronal plane but along a vertical line on the body midline. In experiment 5, the hand was placed in 3 positions in head-centered coordinates (in front of the head, beside the head, and behind the head) while the head either faced straight ahead or was rotated by 90°. Therefore, in head-centered coordinates, 2 pairs of these conditions (“side” and “rotated side”; “front” and “rotated front”; indicated by dashed boxes in the top left) were identical. In experiment 6, the hand was placed in 5 positions, each of which was present in at least 1 of experiments 1–5. Top left: an overall view of the postures used in all experiments.