Motor Control 2 - Corticobulbar Tract Flashcards
what parts of cortex contribute to UMN
PSC
PMS
Pre MA
somatic motor association area
course of the corticobulbar tract
cortex gives out UMN
corona radiata
genu of internal capsule
brainstem
synapses with cranial nuclei
LMN to muscle
what is a supranuclear fibre
UMN
when passing through the internal capsule what is the difference between the corticobulbar and corticospinal tracts
bulbar in genu
spinal in post limb
oculomotor path
UMN synapses bilaterally
LMN are ipsilateral
trochlear path
UMN synapses bilaterally
LMN are contralateral
trigeminal path
UMN synapses bilaterally
LMN are ipsilateral
abducens path
UMN synapses bilaterally
LMN are ipsilateral
facial upper nucleus path
UMN synapses bilaterally
LMN are ipsilateral
facial lower nucleus path
UMN synapses unilaterally and contralaterally
LMN are ipsilateral
nucleus ambiguus path
UMN synapses bilaterally
LMN are ipsilateral
which CN are involved in the nucleus ambiguus
glossopharyngeal
vagus
cranial accessory
hypoglossal path
UMN synapses unilaterally and contralaterally
LMN are ipsilateral
spinal accessory path
UMN synapses bilaterally
LMN are ipsilateral to SCM and contralateral to trapezius
which CN are exceptions to the golden rule of the corticobulbar tract
trochlear
facial
hypoglossal
pseudobulbar palsy
this is a mild weakening of affected muscles when there is a UMN lesion in the corticobulbar tract everywhere except the lower facial and hypoglossal as these do not have bilateral synapsing of the UMN so don’t have contralateral backup - these suffer paralysis / overaction of contralateral muscles
UMN lesion in lower facial nucleus
this should supply the contralateral lower quadrant of face so get paralysis here
LMN lesion in lower facial nucleus
all facial muscles paralysed on ipsilateral side
UMN lesion in hypoglossal
the muscle on each side of the tongue push against each other to keep the tongue central - so when the UMN is injured the tongue deviates to contralateral side when stuck out as the UMN synapses unilaterally and contralaterally
LMN in hypoglossal
tongue deviates to the ipsilateral side as the LMN is ipsilateral to the nucleus and controls the ipsi muscle in the tongue
