Motor-descending Pathways Flashcards
What does the medial motor tracts control?
Postural and girdle control (unconscious)
What are the 4 medial motor tracts that regulate posture/gross movement?
Reticulospinal
Medial vestibulospinal
Lateral vestibulospinal
Medial corticospinal
What do the LMN in the reticulospinal tract do?
Postural and gross limb movement (bilaterally)
What are the actions of the Reticulospinal tract?
Active during walking
Anticipatory postural adjustments
Reaching movements
Neck reflexes (turning head to see something)
What do the LMN control in the medial vestibulospinal tract?
Neck and upper back muscles
What are the actions that occur in the medial vestibulospinal tract?
Medial information about head movement and position
Help maintain an erect posture
What do the LMN do in the lateral vestibulospinal tract?
Activate extensors and inhibit flexors
What are the actions of the lateral vestibulospinal tract?
Lateral info about gravity
Center of gravity
Response to destabilization
Help maintain an erect posture
What do the LMN control in the medial corticospinal tract (anterior corticospinal)?
Neck, shoulders, and trunk
Why is the medial corticospinal (anterior corticospinal) tract considered a pyramidal tract?
Because it descends through the pyramidal sections of the medulla
What do lateral motor tracts do?
Fractionated movement of face, neck, and distal limbs
What are the tracts associated with the lateral motor tracts?
Rubrospinal tract
Lateral corticospinal tract
What does the rubrospinal tract do?
Minor contribution to control of upper limb distal extensor muscles
What is the most clinically important descending motor pathway?
Lateral corticospinal tract
What does the lateral corticospinal tract do?
Controls movement of the extremities (pyramidal tract)
How do lesions work in the lateral corticospinal tract?
Lesion above pyramidal decussation = contralateral weakness
Lesion below the pyramidal decussation = ipsilateral weakness
What do the corticospinal brainstem tracts (corticobulbar) control?
LMN of the face, tongue, pharynx, SCM, and upper trap
What are the LMN of the lower portion of the face controlled by on the corticospinal brainstem tracts?
Contralateral neurons
What are the LMN of the upper portion of the face controlled by on the corticospinal brainstem tracts?
Bilaterally
What do the non specific motor tracts do?
Involved in excessive limbic activity in the emotional motor system (performance anxiety)
Where do the non specific UMN descend from?
Locus coeruleus and raphe nuclei
What do non specific UMN enhance?
Activity of interneurons and LMN
What are the two non specific motor tracts?
Ceruleospinal
Raphespinal
What is the function of the ceruleospinal tract?
Tonic facilitation of LMN
Releases norepinephrine
What is the function of the raphespinal tract?
Releases serotonin
