Spinal Tracts

Ascending tracts includes

DCML, ALS (spinothalamic, spinoreticular, spinomesenphalic, spinotectal), spinocerebellar

DCML

Discriminative touch

ALS

Pain and temp (lateral tract), crude touch (ventral tract)

Spinocerebellar

High accuracy: muscle and joints

Internal feedback: measures gray matter excitation in spinal cord

High accuracy pathways

Posterior spinocerebellar (LE), cuneocerebellar (UE)

Internal feedback pathways

Anterior spinocerebellar (LE), rostrospinocerebellar (UE)

Conscious relay

Transmits info about location and type of stimulus

• DCML, ALS

Divergent relay

Transmits info to many areas of cortex/brainstem, info used at conscious and unconscious levels

• ALS

Unconscious relay

Unconscious proprioception

• Spinocerebellar

Ascending tracts

Sensory

Descending tracts

Motor

Medial activation system location

Anterior funiculus

Medial activation system role

Postural control, proximal extension, muscle tone

Lateral activation system location

Lateral funiculus

Lateral activation system role

Fine movement, distal flexion

Corticospinal tract

Lateral activation system

UE/neck are more medial

Medial tract → ipsilateral

Lateral tract → contralateral

Vestibulospinal tract

Medial activation system - Proximal extensors, postural control

• Tonically active → always active at some point

Regulation of postural reflexes, coordination of head and body in space

Medial tract → neck extension, postural control → bilateral

Lateral tract → trunk extension, postural control → ipsilateral

Medial Reticulospinal tract

Medial activation system

Proximal extensor tone → ipsilateral

Lateral reticulospinal tract

Lateral activation system

Inhibits extension, helps with flexion but doesn’t specifically do flexion → bilateral

Rubrospinal tract

Lateral activation system

Distal flexion → contralateral

Lesion = intention tremors

Tectospinal tract

Medial activation system

Coordinate head and eye movement, spatial awareness

Extensors and postural control

Central cord lesion

Lose pain and temp bilaterally

Larger lesion: UE motor function can be impaired

Brown-Sequard lesion (Hemisection)

Lose ipsilateral discriminative touch and proprioception

Ipsilateral paralysis

Contralateral pain and temp

Anterior cord syndrome

Lose pain and temp bilaterally

Bilateral paralysis

Discriminative touch and proprioception are spared (DCML)