Abstract
The correlation between the average τ^- and the standard deviation S of the discharge-interval-time-series of a single NMU has been discussed statistically, using domestic fowls, rabbits, goats and dogs under the conditions of standing on various inclined or moving boards. The τ^--S curve of the animals with poorly developed pyramidal tract, that is, domestic fowls, rabbits and goats, is a simple straight line, in which the horizontal part is indistinguishable from the ascending part. However, dogs having the well developed pyramidal pathway have the same type of τ^--S curve as that of the human skeletal muscles. It might be supposed that the former maintains a standing posture in any condion by the action of the subcortical nervous system, evoked by the afferent impulses from the receptors of the joint, tendon, muscle and other parts of the body. On the contrary, in the latter the inexpedient conditions may activate the cartical motor area to prevent the collapse of a stable stance and bring forth the kinetic function of the neuromuscular system. The principles governing the τ^--S curve of the animals with the highly developed pyramidal tract, i.e., dog and cat etc., may be considered the same type as that of tne human skeletal muscles.
