These neurons connect the brain to the appropriate level in the spinal cord, from which point nerve signals continue to the muscles by means of the lower motor neurons. The neurotransmitter glutamate transmits the nerve impulses from upper to lower motor neurons where it is detected by glutamatergic receptors.
|corticospinal tract||from the motor cortex to lower motor neurons in the ventral horn of the spinal cord||The major function of this pathway is fine voluntary motor control of the limbs. The pathway also controls voluntary body posture adjustments.|
|corticobulbar tract||from the motor cortex to several nuclei in the pons and medulla||Involved in control of facial and jaw musculature, swallowing and tongue movements.|
|tectospinal tract/colliculospinal tract||from the superior colliculus to lower motor neurons||Involved in involuntary adjustment of head position in response to visual information.|
|rubrospinal tract||from red nucleus to lower motor neurons||Involved in involuntary adjustment of arm position in response to balance information.|
|vestibulospinal tract||from vestibular nuclei, which processes stimuli from semicircular canals||It is responsible for adjusting posture to maintain balance.|
|reticulospinal tract||from reticular formation||Regulates various involuntary motor activities and assists in balance.|