lab 6 - descending pathways Flashcards
Dorsolateral spinal cord pathways terminate and synapse where
lateral MNs and INs
what kind of movements do the Dorsolateral spinal cord pathways serve
single limb movement
Ventromedial spinal cord pathways- terminate and synapse where
on the medial MNs and INs
this info is shared to medial MN on the other sid eof the spinal cord
what kind of movement does the Ventromedial spinal cord pathways serve
axial and proximal limb girdle muscles
dorsolateral pathways
Corticospinal Tract
Rubrospinal Tract
Ventromedial pathways
Ventral CST
Vestibulospinal Tract
Tectospinal Tract
Reticulospinal Tract
Lateral Corticospinal tract (CST) orginates
Pre-central gyrus
Lateral Corticospinal tract (CST) terminates
Lateral MN & IN’s of ventral horn of spinal cord
CST role - info
serving limb muscles
enables fractionation of fingers/hand/UE
modulate sensory info.
where does CST cross and what crosses
Pyramidal decussation of lower medulla
90% of fibers cross to become Lateral CST in SC
10% of fibers do NOT cross (CST) what happen to them
stay ipsilateral to become the ventral corticospinal tract (VCST)
synpase onto medial MN and IN - serves bilateral axial/trunk muscles
Rubrospinal tract orginates
Arises from Red nucleus
Located in the midbrain
rubrospinal tract temrinates
Terminates on lateral MN’s and IN’s of the ventral horn at primarily cervical spinal levels
Rubrospinal tract primary action
to facilitate MN that innervate large muscle movements and fine motor control of UE, primarily serves cervical regions
Vestibulospinal tracts convey impulses from where
convey impulses from the labyrinth
Vestibulospinal tracts two tracts
medial and lateral
medial Vestibulospinal tracts orginates
Medial Vestibular nucleus
medial Vestibulospinal tracts terminates
Terminates on ipsilateral Medial MN’s and IN’s of ventral horn primarily at cervical levels
medial Vestibulospinal tracts function
Activates LMN associated with spinal accessory n: rotation/lifting of head and shoulder blade
movements appropriate for orientation of individual during altered posture and balance
lateral Vestibulospinal tracts orginates
Lateral Vestibular nucleus
lateral Vestibulospinal tracts terminates
Terminates on ipsilateral Medial MN’s and IN’s of ventral horn primarily at ALL spinal levels
lateral Vestibulospinal tracts function
important for maintenance of upright posture and balance via excitation of antigravity/extensor muscles
Vestibulospinal tracts cross
no
Tectospinal tract function
“believed” to direct head movements in response to visual stimuli
Tectospinal tract orginates
Superior colliculus in the midbrain
Tectospinal tract terminates
Terminates on contralateral Medial MN’s and IN’s of ventral horn primarily at cervical levels
Reticulospinal tract role
Coordinates trunk/prox muscle response during limb mvmt via balancing actions b/w extensors and flexors
Reticulospinal tract- lateral role
role in suppressing extensor activity
Reticulospinal tract - medial role
role in facilitating extensor activity
Reticulospinal tract - lateral orginates
neurons in the reticular formation of the medulla
Reticulospinal tract - lateral terminates
Terminates on Medial MN’s and IN’s of ventral horn at all levels of SC
Reticulospinal tract - lateral cross
no
Reticulospinal tract - medial role
role in facilitating extensor activity
Reticulospinal tract - orginates
cells and neurons in the reticular formation of the Pons
Reticulospinal tract - terminates
Terminates on Medial MN’s and IN’s of ventral horn at all levels of SC
Reticulospinal tract - crosses
no
Corticobulbar tract- what is it
any descending cranial nerve-related motor axons from cerebral cortex traveling to the respective contralateral nuclei – which in turn gives rise to the respective cranial nerve
Corticobulbar tract path
lateral aspect of motor cortex (pre-central gyrus) and association areas (pre-motor, etc…) to CN nuclei of contralateral brainstem
