Upper motor neuron lesions
Upper motor neurons have axons that descend from the brain stem and cerebrum and synapse on lower motor neurons (i.e., cell bodies that begin and terminate in the CNS that do not exit the central nervous system but influence lower motor neurons). Upper motor neuron lesions typically present with increased or exaggerated reflexes; additional findings can include:

• Paralysis opposite side of lesion
• Weakness
• Changes in muscle tone (hypertonic, hypotonic or fluctuating)
• No significant muscle atrophy unless following a long period of disuse
• No fasciculation or fibrillation 
• Babinski reflex may be present
• Hoffman's reflex may be present

Upper motor neuron dysfunction can affect cutaneous reflexes, timing of muscle activation, and can cause paresis and/or result in different types of spasticity, rigidity or hypotonia. Common examples of UMNL’s include spinal cord injury, cerebral vascular accident, traumatic brain injury and Parkinson’s disease.