We now have to show how the neurons signal the muscles to contract (or relax) in order to rotate the upper leg, which then rotates the knee, which in turn rotates the lower leg, which then rotates the foot relative to the hip. At this point we apply a further simplification by just showing a few neurons that are attached to the muscles.
We simplify the action by focusing on the hip joint, and by ignoring any muscles needed to keep the knee straight or to hold the ankle. We also ignore musles required for balancing, etc.
Basic nerve encoding schemes predominantly seem to be of two types: labeled-line code, and frequency code.� Labeled-line code just means that a different nerve is used to the arm rather than to the leg (different destination).� A different nerve might also be used to tell the elbow to straighten up rather than bending further (different function).� Frequency code means more pulses per second are sent if the action should be faster or more intense.� Both of these methods of encoding seem well suited for present-moment action.