As we previously saw, the afferent axons from the Golgi tendon organ serve as detectors of muscle stretch. There are two populations of afferent axons from the Golgi tendon organ, with different sensitivities to stretch. The more sensitive afferent axons tell the brain how hard the muscle is pulling. The less sensitive ones have an additional function. Their terminal buttons synapse on spinal cord interneurons-neurons that reside entirely within the gray matter of the spinal cord and serve to interconnect other spinal neurons. These intemeurons synapse on the alpha motor neurons serving the same muscle. The terminal buttons liberate glycine and hence produce inhibitory postsynaptic potentials on the motor neurons. (See Figure 8. 7.) The function of this reflex pathway is to decrease the strength of muscular contraction when there I danger of damage to the tendons or bones to which the muscle are attached. Weight lifters can lift heavier weights if their Golgi tendon organs are deactivated with injections of a local anesthetic, but they run the risk of pulling the tendon away from the bone or even breaking the bone