Brainstem Centers Flashcards
Cortical Structures that send input to the spinal coard are
primary motor cortex
prefrontal cortex
somatosensory and parietal association cortex
Subcortical structures that send input to the sp cd are:
basal ganglia
cerebellum
thalamus
Rubrospinal tract:
Many small __________ neurons in the red nucleus project to inferior olive
parvocells
Neurons in the rubrospinal tract decussate at the level of the
Midbrain at the ventral tegmental decussation
The rubrospinal tract begins in
the midbrain at the red nucleus… then decussates right away in the ventral tegmental decussation
Once the inferior olivary nucleus recieve the rubrospinal tract, it sends input to the :
cerebellum or the (olivo-cerebellar tract)
Info from olive to cerebellum from rubrospinal tract is to
modulate cerebellum activity ( participates in learning and memory fnx of cerebellum)
rubrospinal: from cerebellum info goes to _____ and send contralateral to red nucleus
thalamus
Red nucleus via olivary nucleus will provide feedback loop to cerebellum to allow for:
feedback loop to allow adaption of cerebellar circuits
~~ keeps movements non-jerky
Decorticate Posturing/Rigidity seen when
cortical input to red nucleus is eliminated while cerebellar to red nuclues and rubrospinal is intact
Decorticate posture:
Cortical input to red nucleus is:
Cerebellar input to red nucleus is:
Rubrospinal tract is:
ELIMATED
intact
intact
In Decorticate posture/Rigitidy we see
upper limbs flexed to core and extention of lower limbs
cortex can no longer communated with brain stem
Decorticate posture is due to damage in the:
upper midbrain
Lower midbrain damage–>
Decerebrate posturing
Symptoms of decerebrate syndrome/lower midbrain damage
Patient extends upper and lower limbs
patients extends upper and lower limbs… damage in
lower midbrain
Benedikts sydrome is:
unilateral lesion of red nuclues in the midbrain
Symptoms of benedikts syndrome
CN III injury: ipsilateral oculomotor palsy (eye deviates laterally, ptosis, pupil is fixed and dialated)
Contralateral tremor
CN III injury: ipsilateral oculomotor palsy (eye deviates laterally, ptosis, pupil is fixed and dialated)
Contralateral tremor
Benedikts syndrome or unilateral lesion of red nucleus
rubrospinal tract lesion usually occurs in conjunction with:
corticospinal tract lesions
Pathway that facilitates reflexive turning movments of the eyes and head and upward gazee
Tectospinal tract
_________fibers arise in retina, visual cortex and inferior paretal lobes to project to superior colliculus
Corticotectal fibers
Tectospinal fibers start in the ______ and decussate in the _______
superior colliculus
dorsal tegmentum
(in the midbrain)
Tectospinal fiberes end in the ipsi/contralateral cervicle spinal cord at the _________
Contralateral
CN XI nucleus with sternodcleomastoid
Additional fibers from superior colliculus (part of tectospinal) project here to control exraoccular upward gaze
pontime paramedian reticular fomration–>MLF
Pairnauads syndrome/Dorsal midbrain syndrome/Collicular syndrome
lesion in region of superior colliculi or posterior commisure leads to eye abnormalities
Lesion in the supeiror colliculi or posterior commisure leads to eye abnormalities
Collicular syndrome/Parinauds syndrome/Dorsal midbrain
Symptoms of Parinuads syndrome
(lesion of superor colliculi)
Loss of upward gaze
large, irregular pupils w/ light-near dissociation
-eyelid abnormalities (retract or ptosis)
convergance-retraction-nystagmus
(lesion of superor colliculi)
impaired visual gaze
large, irregular pupils w/ light-near dissociation (pupils don’t constrict with light but do with accomidations)
-eyelid abnormalities (retract or ptosis)
convergance-retraction-nystagmus
symptoms of parinurads syndrome
causes of Parinuads syndrome
Pineal tumor, hydrocephalus
Input to superior colliculi
visual cortex
Inputs to teh vestibular nuclei
vestibular nerve and cerebellum
Cell bodies in the vestibular nuclei w/in brainstem
Lateral vestibulospinal tract
Lateral vestibulospinal tract projects ipsi/contralateral within _________ to ALL levels of sp cd
Ipsilaterally
anterior folliculus
Lateral vestibulospinal tract functions
innervates extensor (antigravity) muscles in trunk/lower limbs for balance
Lesion of vestibular nerve or vestibular nucleus–>
stumbling and or falling toward SIDE of lesion
Causes of Lateral Medullary syndrome
occlusion of vertebral artery or PICA
Symptoms of Lateral Medullary Syndrome
Side of lesion: dysphagia, dysarthria, lower gag reflex, loss of pain and temp from face, vertigo, nausea and vomiting, nystagmus
Contralateral to lesion: loss of pain/temp from body
Side of lesion: dysphagia, dysarthria, lower gag reflex, loss of pain and temp from face, vertigo, nausea and vomiting, nystagmus
Contralateral to lesion: loss of pain/temp from body
Lateral medullary symtom
What cuases the dysphagia, dysarthria, and loss of gag reflex from lateral medullary sydnrome
nuclues ambiguis of CN XI and X on medulla
see a checkerboard pattern of loss of pain and temp from face (ipsilateral) and body (contralateral)
lateral medullary syndrome ( PICA or vertebral artery occulsion)
Input to medial vestibulospinal nucleus
vestibular nuclei and cerebellum
MVST description:
cell bodies in vestibular nuclie are w/in brainstem and projects to _______ within anterior funiclus to :
sp cd
and LMNs associated with spinal accessory nerve
projectes to cervical spinal cord and to LMNs associated with spinal accessory nerve
MVST
Functionof MVST
adjust head postion in response to posture change
coordiates eye movement with each other
Vestibuloccular reflex
what adjust head position in response to posture change, coordinates eye movment together and a VOR
medial vestibular tract
What other CNs do MVST project to through the MLF
CN III, IV, VI to coordiante eye movements with each other
Controls neck muscles
Medial VST
excites axial extensor ms (antigravity)
Lateral VST
Input to reticular nuclei is the
cortex
Medullary and Lateral RST is:
bilateral and INHIBITS LMNS to inhibit extensor msl contraction
what has bilateral innervation to inhibiti LMNS to prevent extensor msl contraction
Medullary and Lateral reticulospinal Tract (both reticulospinal tract)
Reticulospinal tracts are composed of scattered groups of neuron cell bodies and fibers that extend throughout the:
brainstem
REticulospinal tract input to reticular nuclei is
cortex
Reticulospinal tract from Medullary/lateral RST is:
bilaterall and inhibits LMNs to inhibit msl contration
Reticulospinal tract from Pontine/ medial RST:
ipsliateral and Excites LMNS–> stimulates extensor msl contraction
Why do we see symptoms we do on Decerebrate rigidity
midbrain transsection removes excitatory coritcal input to the INHIBITORY LRST which ascending input to MRST is intact
the faciliaroy influce of MRST is unopposed by inhibitor influence of LRST so we see extensor motor neurons.
