Tract | Location of Upper Motor Neurons | Destination | Site of Crossover | Action |
CORTICOSPINAL Corticobulbar | Primary Motor Cortex (pyramidal cells) | Cranial Nerves III – XII | Brainstem | Conscious Motor control of skeletal muscles |
Anterior (ventral) corticospinal | Primary Motor Cortex (pyramidal cells) | Lower motor neurons of anterior grey horns of spinal cord | Level of lower motor neuron | Conscious Motor control of skeletal muscles |
Lateral corticospina | Primary Motor Cortex (pyramidal cells) | Lower motor neurons of anterior grey horns of spinal cord | Pyramids of medulla oblongata | Conscious Motor control of skeletal muscles |
MEDIAL Vestibulospinal | Vestibular nucleus (at pontomedullary junction) | Lower motor neurons of anterior grey horn of spinal cord | NONE | Subconscious regulation of balance and muscle tone |
Tectospinal | Tectum (the superioir and colliculi of midbrain) | Lower motor neurons of anterior grey horn of spinal cord (cervical region only) | Brainstem | Subconscious regulation of muscles in head, neck and upper limb in response to auditory and visual stimuli |
Reticulospinal | Reticular Formation of pons and medulla | Lower motor neurons of anterior grey horn of spinal cord | NONE | Subconscious regulation of reflexes |
LATERAL Rubrospianl | Red nuclei of the modbrain | Lower motor neurons of anterior grey horn of spinal cord | Brainstem (midbrain) | Subconcious regulation of limb muscle tone and movement |
