Brainstem Centers that influence motor activity Flashcards
What is the pathway of the rubrospinal pathway ?
Red Nucleus> decussates in teh anterior tegmentum (ventral part of brainstem)> descend in the Lateral Funiculus (with the lateral CST). This will provide a functional feedback loop for cerebrellum actions. > Spinal cord
What is the main focus of the RST ?
Influencing motor control of distal limbs mainly forelimbs.
What are the large cells from the redu nucleus called
Magnocellular
Where is the injury in decorticate posturing ?
The brainstem is transected rostral to the superior colliculus
With decorticate posturing which control centers have input to the LMNs
NO cortical input
Cerebellar input to the red nucleus is intact
Rubrospinal tract is intact
How do patients with decorticate lesions present ?
Patients exhibit upper limbs flexed at the elbow and lower limbs extended.
How do patients with decerebrate lesions present ?
Patients exhibit upper limbs as well as lower limbs extended.
What is midbrain syndrome
Unilateral lesion of the red nucleus. Also results in oculomotor ipsilateral nerve palsy since they are passing through the red nucleus to get to the eyes.
Physical sign is controlateral tremor.
What is the Tectospinal tract TST
Motor pathway from the superior colliculus to motor neurons controlling neck muscles
What is the function of the Tectospinal tract
To coordinate reflexive turning movements of the head and eyes.
It facilitates the upward gaze.
Pathway of Tectospinal Tract
Retina/visual cortex> motor neurons controlling neck> terminates on accessory nucleus
How often is lesion of the Tectospinal tract seen ?
It is virtually unseen
Where does the Tectospinal Tract decussate ?
It decussates immediately on the level with the superior colliculus . It then travels in the anterior funiculus but only gets to the cervical spinal level
What is Parinaud’s Syndrome
Inability to look up (loss of upward gaze) as a result of superior colliculi and posterior commissure damage.
What are some common causes of Parinaud’s Syndrome
Pineal gland tumor, hydrocephalis resulting from aqueductal stenosis.
Where does the Vestibular Nuclei get its input
Vestibulo nerve
Flocculus of the Cerebellum
Describe the lateral vestibulo spinal tract
The cell bodies are in the vestibular nuclei.
The projections are to anterior funiculus within ipsilateral spinal cord levels
What is the function of the Lateral Vestibulo Spinal Tract
Innervates extensor antigravity muscles, mainly in the trunk and lower limbs to maintain balance and posture.
Where does the lateral vestibulo spinal originate
In the Pons. The Lateral Vestibular nucleus is in the pons
Which part of the ear is information coming from
It is coming from the vestibule of the inner ear, of the vestibular component of the VC, projecting to the vestibular nuclei.
Where is the vestibular nuclei
It is in the lateral brainstem. It is in the caudal pons and the rostral medulla.
Patient presentation if there is a LVST lesion
patient will fall to the lesioned side
Possible causes of LVST lesion
Vertebral artery occlusion
PICA occlusion
These are the vessels that are associated with the medulla below the basilar artery
LVST lesion Patient symptoms
Loss of speech, swallowing, gag reflex, pain and temperature from the face on that side. Also vertigo and nausea. On the body: contralateral pain and temperature.
