Observations on the morphology of intracellularly stained γ-motoneurons in relation to their axon conduction velocity

Abstract

Hindlimb γ-motoneurons of adult cats were stained intracellularly with horseradish peroxidase. The γ-motor-axons had intramedullary diameters between 2.0 μm and 2.4 μm and lacked recurrent collaterals. The conduction velocity of the γ-motor-axons (20-29 m/sec) was close to what could be predicted from the relationship between conduction velocity and intramedullary diameter of much thicker adult α-motor-axons. However, the γ-motor-axons were conducting much faster than α-motor-axons of 1-week-old kittens in spite of the fact that these two types of axons had about the same dimensions intramedullarly. © 1979.