Summary (UMNs, positioning, etc.) from RF notes Flashcards
control of muscle activity, whether by reflex activity, postural shifts, or voluntary movement activty, are based on integrity of…
both the UMN and LMN components
systems that modulate the activity of the UMNs, such as the cerebellum and basal ganglia
lateral corticospinal pathway
- cell bodies in areas…
- terminate in…
cell bodies in areas 8, 6, 4, 3, 1, 2, 5
terminate in lateral part of contralateral ventral horn; dorsal horn (from 3, 1, 2, 5)
lateral corticospinal pathway
- function
- fibers ending in the dorsal horn are involved in…
voluntary motor activity of proximal and distal limb musculature
fractionated (fine) motor activity
fibers ending in the dorsal horn are involved in feedback and modulation of incoming sensory signals specific to ongoing motor activity
anterior (medial) corticospinal pathway
- cell body location
- terminate in…
- function
cell bodies in areas 4, 6
terminate in medial part of contra ventral horn
voluntary activity of axial musculature
rubrospinal pathway
- cell bodies in…
- terminate in…
- function
cell bodies in Red Nucleus
terminate in lateral part of contra ventral horn
-primarily cervical region
voluntary fractionated activity of distal UE musculature
-primarily flexors of the digits
tectospinal pathway
- cell body location
- terminate in…
- function
cell bodies in superior colliculus
terminate in the medial part of contra ventral horn
-primarily cervical region
coordination of neck movements with eye movements, reflexive turning toward stimulus
lateral vestibulospinal pathway
- cell body location
- terminate in…
- function
cell bodies primarily in lateral vestibular nucleus
terminate in ipsilateral ventral horns of all levels, but heavier in lower thoracic through sacral levels
facilitory to extensor LMNs as response to head movement
medial vestibulospinal pathway
- cell body location
- terminate in…
- function
cell bodies in medial and inferior vestibular nuclei
terminate bilaterally in ventral horn of cervical and upper thoracic cord
facilitory to ipsilateral LMNs of neck
inhibitory to contra LMNs of neck
facilitory to extensors of upper extremities
lateral (medullary) reticulospinal pathway
- cell body location
- terminate in…
- function
cell bodies in medullary reticular formation
-terminate in lateral part of ventral horn on interneurons effecting bilateral segmental LMNs
functions primarily to facilitate flexor LMNs and thus decrease the activity of extensor LMNs
medial (pontine) reticulospinal pathway
- cell body location
- terminate in…
- function
cell bodies in pontine reticular formation
terminate in medial part of ventral horn on interneurons effecting bilateral segmental LMNs
-primarily in the cervical region
facilitates extensors of the UE bilaterally
function of brainstem pathways
help in maintaining static and reactive posture through
- vestibular input
- ascending sensory information that is entering the reticular formation
- cerebellar influence via the red nucleus, vestibular nuclei, and reticular formation
brainstem influence is mediated by…
activity on both the alph and gamma motor neurons, mostly be interneuronal connections
the main pathway necessary to generate volitional movement is the…
lateral corticospinal tract
lateral corticospinal tract
- receives info from…
- under the modulatory influence of…
area 6
-premotor and supplementary motor cortical regions
area 4
-primary motor cortex
under modulatory influence of cerebellum and basal ganglia
what pathway runs parallel to the lateral corticospinal tract
-where does it travel
corticoreticulospinal pathway
area 6 to pontine and medullary reticular nuclei
what functions dies area 6 serve?
direct corticospinal fibers
direct input to area 4
indirect corticoreticulospinal fibers
anticipatory postural responses are prepared through…
corticospinal projections from the supplementary motor cortex
influence from the corticospinal projections from the supplementary motor cortex onto the reticulospinal pathways is important for…
regulating the excitability of these pathways
decerebrate and decorticate posture are an example of changes in…
descending control over motor activity
decerebrate posture
-occurs when…
occurs when brainstem pathways are disconnected from the cortex by a midbrain lesion caudal to the red nucleus
decerebrate posture
-lateral vestibulospinal tract function
maintains tonic activity over extensors of the upper and lower extremities
decerebrate posture
- reticulospinal tracts are…
- why is this important?
devoid of influence from cortex due to lesion
lets the vestibulospinal pathways maintain their activity without antagonistic activity of the reticulospinal paths
decerebrate posture
-what else is lost
flexor influence from rubrospinal tract is lost
decerebrate posture
-what is the resultant posture
extension of both upper and lower extremities
decorticate posture
-occurs when…
occurs when lesion is above the level of the red nucleus
decorticate posture
-what causes the posturing
rubrospinal influence on UE flexors causes flexor posture in UE
extensor tone is still dominant in LE
decorticate posture
-what is the resultant posture
flexion at the elbow in UE
extension of the LE
