The inverse myostatic reflex

(B) requires influence of supraspinal fibres to be activated > The Golgi tendon reflex is a normal component of the reflex arc of the peripheral nervous system. In a Golgi tendon reflex, skeletal muscle contraction causes the antagonist muscle to simultaneously lengthen and relax.> This reflex is also called the inverse myotatic reflex, because it is the inverse of the stretch reflex. Though muscle tension is in- creasing during the contraction, alpha motor neurons in the spinal cord supplying the muscle are inhibited.> However, antagonistic muscles are activated.The receptor for the inverse stretch reflex is in the Golgi tendon organ (Figure 9-5).> This organ consists of a netlike collection of knobby nerve endings among the fascicles of a tendon. There are 3-25 muscle fibers per tendon organ.> The fibers from the Golgi tendon organs make up the lb group of myelinated, rapidly conducting sensory nerve fibers.> Stimulation of these lb fibers leads to the production of IPSPs on the motor neurons that supply the muscle from which the fibers arise.> The lb fibers end in the spinal cord on inhibitory interneurons that in turn terminate directly on the motor neurons.> They also make excitatory connections with motor neurons supplying antagonists to the muscle.