Brainstem centers that influence motor activity Flashcards
1
Q
Rubrospinal Tract
A
- function in non-human primates: contributes to control of forelimbs
- cell bodies in red nucles
- axons decussate in anterior tegmentum
- descend in lateral funiculus to cervical spinal cord
- Function in HUmans: provides feedback loop for cerebellum
2
Q
Decorticate Posturing/Rigidity
A
“Arms to the core” (corpse pose)
- cortical input to red nucleus is eliminated
- cerebellar input to red nucleus is intact
- rubrospinal tract is intact
- seen in patients with upper brainstem damage: upper limbs flexed at the elbow and lower limbs extended
3
Q
Bernedikt’s Syndrome
A
- unilateral lesion of red nucleus
- on side of lesion: oculomotor palsy
- contralateral tremor
4
Q
Tectospinal Tracts
A
- “SQUIRREL!!” turn head and eyes to look
- input to superior colliculi: visual cortex
- TST Description- motor pathway from superior colliculi to motor neurons controlling neck muscles
- Function:
- coordinate reflexive turning movements of head and eyes
- superior colliculus also facilitates upwards gaze
5
Q
Lateral Vestibulospinal Tract
A
- input to vestibular nuclei
- vestibular nerve
- cerebellum
- LVST Description::
- cell bodies in vestibular nuclei wihtin the brainstem
- projects ipsilaterally within anterior funiculus to ALL LEVELS of spinal cord
- LVST Function:
- innervates extensor (antigravity) muscles mainly in the trunk and lower limbs to maintain balance and posture
6
Q
Medial Vestibulospinal tract
A
- input to vestibular nuclei
- vestibular nerve
- cerebellum
- MVST Description:
- cell bodies in the vestibular nuclei within the brainstem
- projects bilaterally within the anterior funiculus to cervical spinal cord
7
Q
Medial Vestibulospinal Tract
A
- input to vestibular nuclei
- vestibular nerve
- cerebellum
- MVST Description:
- cell bodies in vestibular nuclei within brainstem
- projects bilaterally within anterior funiculus to cervical spinal cord
- MCST Function:
- adjusts head position in response to postural change
- coordinate eye movements with each other
- vestibuloocular reflex: coordinates eye movements to compensate for head mvoements
8
Q
MVST
A
coordinates eye movements with each other
- vestibular nuclei send sensory input regarding head movement to contralateral abducens nuclueus
- each abducens nucleus is in communication (via the MLF) with the contralateral oculomotor nucleus
- the eyes are yoked together resulting in conjugate horizontal gaze
9
Q
Internuclear Opthalmoplegia
A
lesions of medial longitudinal fasiculus between the nuclei of CN VI and CNIII
- impaired adduction ipsilateral to lesion
- horizontal nystagmus of abducting eye contralateral to lesion
10
Q
Lateral Medullary Syndrome
A
- causes: vertebral artery or PICA occulsions
- on side of lesion: *dysphagia, dysarthria, decreased gag reflex
- loss of pain and temp from the face
- vertigo, nausea, vomiting, nystagmus
- contralateral to lesion
- loss of pain and temp sensation from the body
11
Q
Reticulospinal Tracts
A
- input to reticular nuclei:cortex
- Medullary/Lateral RST
- Pontine/Medial RST
12
Q
Medullary/Lateral RST
A
- bilateral
- inhibits LMNs which inhibits extensor muscle contraction
- Mellow
13
Q
Pontine/Medial RST
A
- ipsilateral
- excites LMNs which stimulates extensor muscle contraction
- Pumped up
14
Q
Decerebrate Posturing/Rigidity
A
-cortex is no longer communicating with the reticular formation nuclei. normally the cortex excites the medullary pathway and inhibits the pontine pathway so in this injury they aren’t mellow and don’t have inhibition of being pumped up
15
Q
Lateral Motor Pathways
A
- Lateral Corticospinal Tract
- Rubrospinal Tract
