Upper Motor Neuron

Question 1

UMN vs LMN

Answer 1

cell bodies in cerebral cortex or brain stem, axons descend in white matter to synapse in grey matter w/ local circuit neurons or LMN
involved with the initiation, maintainence and planning of voluntary movements rather than the production
regulation of muscle tone, control of posture and basic navigational movements

Question 2

Corticospinal

Answer 2

cerebral cortex -> internal capsule -> crus cerebri -> pons -> medulla -> lat. tract -> ventral horn of cervical and upper thoracic seg
MUSCULATURE OF BODY

Question 3

Corticobulbar

Answer 3

primary motor cortex -> brainstem -> motor nuclei of cranial nerves
MUSCULATURE OF THE HEAD

Question 4

Vestibulospinal

Answer 4

vestibular nuclei -> spinal cord
ipsilateral innervation
medial and lateral tracts (MVST and LVST)
BALANCE & POSTURE

Question 5

Ruprospinal

Answer 5

red nucleus -> decussate -> spinal cord

contralateral innervation

Question 6

Reticulospinal

Answer 6

Medial: pons (voluntary) -> increase in MUSCLE TONE
Lateral: medulla (involuntary) -> decrease in MUSCLE TONE
Ipsilateral innervation

Question 7

Tectospinal

Answer 7

superior colliculus -> cervical levels of spinal cord

Contralateral innervation

Question 8

Damage to UMN

Answer 8

Paresis: delay or absence of protraction of limb
Hypertonia: loss of inhib. to GMN = increased firing causes shortening
Spasticity: when muscle is stretched increase Type Ia firing and excessive contraction, increase in muscle tone WHEN MOVING
Hyperreflexia: LMN released from inhibition, sim to spasticity