Figure 1.

Surgical view of the left leg showing the acute dissection and the methods used to establish two-channel CMAP recording and nerve stimulation. Wire-hook recording electrodes were inserted into the belly of the lateral and medial gastrocnemius muscles (black arrows) and Achilles tendon (white arrow in the upper right). A grounding electrode was placed under the skin of the back of the rat (white arrow on the left). The bipolar stimulating nerve cuff electrode with its connecting wires was wrapped around the proximal sciatic nerve at the level of the sciatic notch (star). To isolate motor unit activation corresponding only to the tibial (T) nerve, and to prevent signal interference, the sural (S) and peroneal (P) nerves were cut. The tibial nerve was crushed just distal to the point of sural nerve take-off. For orientation, the rostral direction is down to the left.