Tract
Function
Origin
Crossed
Termination
Corticospinal
Voluntary (skilled) movement
Motor (some sensory) cerebral cortex
Majority cross (lateral corticospinal tract) as pyramidal decussation (in medulla)
Intermediate gray and ventral horn
Rubrospinal
Facilitates flexor and inhibits extensor muscle groups
Red nucleus
Yes; ventral tegmental decussation (in midbrain)
Intermediate gray and ventral horn
Medullary reticulospinal
Facilitates/inhibits muscle groups
Medullary reticular formation
Some cross (others remain uncrossed)
Intermediate gray and ventral horn
Pontine reticulospinal
Facilitates/inhibits muscle groups
Pontine reticular formation
No
Ventral horn
Lateral vestibulospinal
Facilitates antigravity muscles
Lateral vestibular nucleus
No
Ventral horn
Tectospinal
Reflex postural movements in response to visual, auditory, and somatosensory stimuli
Superior colliculus
Yes; dorsal tegmental decussation (in midbrain)
Ventral horn of cervical segments
Medial vestibulospinal (in MLF)
Coordinates head and eye movements
Medial vestibular nucleus
Some cross (others remain uncrossed)
Ventral horn of cervical segments
Raphespinal
Pain inhibition
Raphe nuclei
No
Dorsal horn
Descending autonomic fibers
Modulates autonomic nervous system functions
Hypothalamus and brain stem nuclei
No
Intermediate gray