[Identification of muscle spindles by direct and indirect electric stimulation of intrafusal muscle fibers].

In two series of experiments on 25 anesthetized deefferented cats methods of quick identification of muscle spindles were used. The first method was based on the postcontractory sensory discharge in a muscle spindle after brief strong electrical stimulation of the muscle nerve. In another approach the concentric electrodes inserted into the muscle were used. If the intrafusal muscle fibers were selectively contracted by direct electrical stimulation the sensory discharge appeared without any increase in the total muscle tension. It seems that these methods enable to identify the unit under study more precisely in comparison with conduction velocity measurements, as the group I and II afferents are sometimes present in muscle nerve from joint and deep tissues.