 The upper and lower motor neurons. Injuries to the motor pathways result in paralysis. The extent of the paralysis depends on the type and location of the injury. Damage to the motor neurons in the frontal cortex or their tracts results in upper motor neuron syndrome. For example, if the left lateral corticospinal tract is damaged at the second cervical vertebra, control of the left upper and lower limbs is lost. Upper motor neuron syndrome is characterized by spastic paralysis where little atrophy of the muscle occurs. However, uncoordinated hyperreflex activities where muscle tone is increased cause spastic movements, reflexors and extensors alternately contract. Injuries to the neurons of the fibers in the vertical horn of the cord result in a different type of paralysis. Problems of this sort result in lower motor syndrome. Lower motor neuron syndrome results in flaccid paralysis with loss of movement, tone and reflex activity. The muscle becomes atrophied and flaccid. You have completed this learning activity on the upper and lower motor neurons.