Fig. 10.

Hypothetical schematic diagrams. In the trials shown in diagrams A–C, the correct response side is assumed to be on the right. (A) Voluntary correct response of the right forepaw. (B) Lever activation on the correct response side (right). (C) Lever activation on the incorrect response side (left). The open and closed circles on forepaws indicate the reduction and increase in lever-press force, respectively. Spinal α motor neurons innervating the brachial biceps and triceps are presumed to be active in voluntary movements and to be activated by the stretch reflex caused by lever activation. The reduction in lever-press force of the forepaw opposite the lever activation side (left in B, and right in C) is considered to be caused by the rat’s body being swung back by lever activation. Together, the three diagrams indicate that lever activation on the incorrect response side (C), but not on the correct response side (B), causes changes in forelimb neuromuscular activities and cutaneous afferent activities similar to those associated with voluntary correct responses (A)