what type of neuron can cause muscles to contract
1 Because alpha motor neurons are the only way to stimulate extrafusal muscle fibers, the loss of these neurons causes a decrease in muscle tone. 2  Hyporeflexia. 3  The myotatic (stretch) reflex is weak or absent with lower motor neuron disorders, because the alpha motor neurons that cause muscle contraction are damaged. Fibrillation. 2  With further degeneration of the alpha motor neuron, only remnants of the axons near the muscle fibers remain. 3  These individual axon fibers can also generate spontaneous action potentials; however, these action potentials will only cause individual muscle fibers to contract.