Tracts overview

Question 1

Corticospinal Tract

Answer 1

• Dexterity and fine motor control
• origin: M1, pre-motor, SMA
• M1 UE is medial; M1 LE is lateral
• enters caudal 1/2 of posterior limb of internal capsule
• 85% of fingers cross in pyramidal decussation and becomes lateral corticospinal tract
• the rest doesnt cross and becomes anterior corticospinal tract

Question 2

tectospinal tract (medial pathway)

Answer 2

• crosses in midbrain right away
• involved in coordination of head, neck, and eye movement

Question 3

Vestibulospinal tracts (medial pathway)

Answer 3

• originates in vestibular nuclei
• input from CNVIII
• not directly influences by cortical input

Question 4

Medial Vestibulospinal tract

Answer 4

• descends bilaterally into cervical and high thoracic spinal cord
• head stabilization –> provides stable platform for eyes

Question 5

lateral vestibulospinal tract

Answer 5

• descends ipsilaterally to lumbosacral levels
• excites motor neurons that innervates paravertebral extensors and proximal limb extensors
• antigravity, postural role
• protective extension
• inhibits flexors

Question 6

Reticulospinal tract

Answer 6

• loops system: activates by ipsilateral descending cortical projections and ascending somatosensory systems
• role: may be involved in APAs; maintenance of posture and modulation of muscle tone (especially startle reflex)

Question 7

Medial reticulospinal tract

Answer 7

• ipsilateral
• excitatory effects (extensor)

Question 8

lateral reticulospinal tract

Answer 8

• bilateral
• inhibitory effects on extensor musculature

Question 9

rubrospinal tract (lateral pathway)

Answer 9

-excitatory influence to proximal limb flexors
- UE innervation only

Question 10

Spinothalamic tract

Answer 10

• lateral ST tract: pain and temp
• anterior ST tract: crude touch

Question 11

spinoparabrachial tract

Answer 11

• affective aspect of pain
• activates descending analgesic system

Question 12

spinohypothalamic tract

Answer 12

regulation of neuroendocrine and cardiovascular responses to pain

Question 13

spinocerebellar tracts

Answer 13

• convey pro-reception information from muscle spindles, Golgi tendon organs, and touch and pressure receptors to cerebellum for control of voluntary movements

Question 14

dorsal spinocerebellar tract

Answer 14

• ascends to ipsilateral inferior cerebellar peduncle

Question 15

ventrospinocerebellar tract

Answer 15

ascends to contralateral and ipsilateral superior cerebellar peduncle