Term
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Definition
Cause: bilateral corticobulbar tract lesion
Sx: 1. Dysphagia, dysarthria (Nuc. ambiguus) 2. Tongue paresis 3. Loss of emotional control Common causes: ALS, MS, infarcts |
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Term
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Definition
Cause: infarct Concept: CN V, VII, XII receive direct input from cortex thru IC posterior limb Sx: 1. contra hemiplegia (corticospinal) 2. contra lower face hemiplegia (VII)
3. contra tongue paresis (deviates contra)(XII) Note: V is bilateral, so unless lesion is also, there will be few sx assoc. with V (mastication) |
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Term
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Definition
Cause: periph. CN VII lesion Sx: 1. Ipsi facial hemiparesis (upper + lower) Common cause: viral/inflammatory (idiopathic) |
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Term
Decerebrate posturing/rigidity |
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Definition
Cause: BS transsection caudal to Red nucleus Sx: 1. Arms=extended 2. Legs=extended 3. Muscle tone increased Explanation: lateral reticulospinal is cut off from desc. cortical (+) (it itself is (-)), while medial RST still receives spinal afferents, so it excites postural muscles (extensors)
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Term
Decorticate posturing/rigidity |
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Definition
Cause: loss of desc. cortical input to Red Nuc.; IC post. limb or cortical lesion
Compare: lesion more rostral than in decerebrate Sx: 1. Arms=flexed, legs=extended Why: rubrospinal (cerebellum-->red nuc.) intact, while corticospinal not intact Think: what about corticobulbar tract in this case?
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Term
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Definition
Cause: unilateral Red Nuc. lesion Sx: 1. Contralateral intentional tremor (cerebellar input gone) 2. Postural sx: "UMN" lesion rubrospinal tract 3. Ipsi CN III palsy (emerge from BS at this level) Note: if Occulomotor nuc. lesioned, palsy would be contra |
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Term
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Definition
Cause: lateral spinal cord hemisection Sx: 1. Ipsi loss of fine touch below section (DcML system)
2. Contra loss of pain/temp. by 2 segments below lesion (ALS system)
3. UMN loss: IPSI spastic paralysis (below lesion), Babinski sign 4. LMN loss: flaccid paralysis (local), atrophy, fasciculations |
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Term
Medial Medullary Syndrome |
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Definition
Cause: medial BS infarct (vertebral, PICA) Sx: 1. Contra arm, leg hemiplegia (CSTs) 2. Ipsi tongue flaccid paralysis, atrophy (LMN) 3. Contra loss of fine touch (DcML system) What about tectospinal tract (head, eye mvmt coordination)?
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Term
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Definition
Cause: infarct in lateral midbrain (cerebral peduncles) BV: PCA Sx: 1. Contra hemiplegia: lower face, tongue, limbs (CST) 2. Ipsi CN III palsy (nerve root in IPF) |
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Term
Lesion to posterior limb of the Internal Capsule |
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Definition
Sx: contralateral hemiplegia (complete) |
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Term
Compare: Lateral CST vs. Anterior CST |
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Definition
LCST: 90%
Input: M-I, S-I, PMA Decuss: pyramids All levels, distal limb fine ctrl (contra) ACST: 10% Input: M-I, SMA (bimanual tasks, involves callosum) Decuss: Ant. white commissure (in SC) Only until upper Th, ctrl of bilateral axial & girdle muscles
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Term
Give Brodmann % sx:
1. M-I lesion 2. PMA lesion 3. SMA 4. S-I, post. paretal lobule |
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Definition
1. Contra hemiplegia, loss of fine ctrl (4) 2. Complex movements are slower (6) 3. (Unilateral) Can't do bimanual tasks (6; in longitudinal sulcus in frontal lobe) 4. Polymodal integration deficits, somatic deficits (3, 1, 2; 5, 7) |
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Term
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Definition
Fxn: excites PROXIMAL limb flexors Start: Red Nuc. Input to Red Nuc.: cortex (ipsi), cerebellum (contra, IPNs) Decuss: ventral teg Lateral funiculus (desc.), only cervical Note: implicated in Decorticate rigidity, Benedikt's |
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Term
Medial vs. Lateral Vestibulospinal Tracts
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Definition
MVST: Fxn: VOR (INHIBITS neck mm.)
Fxn: eye movement coordination Start: Medial & Inferior vestibular nuclei
Ascend: MLF (VOR, +) bilateral
Descend: bilateral Terminate: Rexed VII, VIII (only Cervical)
LVST: Fxn: Balance, posture (EXCITES neck, prox limb extensors) All levels, Rexed VII, VIII |
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Term
MVST lesions vs. LVST lesions *VSTs are opposite orientation to geniculate inputs |
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Definition
1. Impaired VOR (common sign of MS) 2. INO (damaged MLF) LVST: 1. Vestibular n. or nuclei=fall toward lesion Lateral Medullary Syndrome (Wallenberg) Cause: PICA, vertebral infarct
Sx: IPSI 1. Vertigo, nausea, nystagmus (vestibular nuclei) 2. Horner's 3. Dysphagia, dysarthria (Nuc. ambiguus) 4. Loss of pain/temp to face (Spinal tract of CN V) Sx: CONTRA 1. Loss of pain/temp. from body (ALS) |
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Term
Tectospinal, corticotectal tracts |
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Definition
Fxn: 1. Reflexive head+eye movements (CC: medial medullary syndrome)
2. Facilitates upward gaze (CC: Parinaud's) Start: Sup. Colliculi Decuss: dorsal teg cervical only, descends in MLF (w/ MVST) |
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Term
Parinaud's Syndrome (Dorsal Midbrain Syndrome) |
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Definition
Cause: pineal gland tumors, hydrocephalus Sx: 1. impaired upgaze 2. large, irregular pupils (accommodate, but no light-reflex) 3. eyelid abnormalities 4. convergence-retraction nystagmus (means convergence impaired) Accommodation controlled by higher centers! |
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Term
Lateral vs. Medial Reticulospinal tract |
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Definition
INPUTs: Vermis
LRST (medulla): inhibits axial muscles Inhibition depends on cortical input (CC: decerebrate) Rexed VII, VIII (IX=excitatory fxns), all levels MRST (pons): excites axial extensor muscles Rexed VII-IX, all levels
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Term
Posture, balance tracts (3) |
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Definition
1. Ant CST (+), to upper Thoracic 2. Lat VST (+), all levels
3. Lat RST (-), Med RST (+), all levels
Posture=extensors +, proximal, axial
Skilled movement=flexors +, distal Balance=vestibular involvement
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Term
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Definition
1. MVST (+ eye mm., - neck mm.) 2. TST (+ reflexive eye-neck movements, upgaze) |
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