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Neuroanatomy Lab III (final)

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Signs of basal ganglia lesions
1) chorea
2) Athetosis
3) Bradykinesia
4) Rigidity
5) tremor at rest
6) hemiballismus
cardinal cerebellar signs
1) ataxia
2) nystagmus
3) intention tremor
Projection directions for the cerebellar peduncles
1) Superior: mostly output
2) Middle: exlusively input (from contralateral pons)
3) Inferior: mostly input (from spinal cord and brainstem)
What output nucleus is in the vermis? What does it control? What peduncle does it leave thru?
Fastigial
Posture/balance
inferior cerebellar peduncle
What output nucleus is in the spinocerebellum (lateral to vermis)? What function does it control? What cerebellar peduncle for output?
Interposed
Limb movememnt
superior
What output nucleus in the cerebrocerebellum? what function? Whcih peduncle does it leave in?
Dentate
motor planning
superior cerebellar peduncle
What deep nucleus in the vestibulocerebellum? what function?
vestibular. function is balance, eye movement control
what do you call cerebellar aferents from the inferior olivary nucleus
climbing fibers
What do you call all other cerebellar aferrents ?
mossy fibers
Summarize limb movement refinement tract
1) Proprioceptive info from limb travels up Dorsal Spinocerebellar tract (DSCT)
2) enters ipsilateral cerebellum via inferior peduncle (I think)
3) goes to spinocerebellar interposed nucleus (medial)
4) one branch of interposed nucleus output leaves via the superior cerebellar peduncle to go to CONTRAlateral VL of thalamus. Synapes and goes on to the motor cortex. Motor cortex sends signal via CST, which decussates in caudal medulla
5) another branch of interposed nucleus output leaves interposed nucleus and goes to contralateral red nucleus. Red nucleus sends motor fibers out that decussate immediately in the midbrain.
Describe motor planning pathway
1) Corticopontine path from one side synapses on ipsilateral pontine nucleus
2) pontine nucleus projects into contralateral pons via MCP
3) Purkinje fibers synapse on dentate nucleus in cerebrocerebellum (lateral)
4) dentate nucleus sends out afferents via SCP to a) contralateral motor cortex via VL of thalamus, and b) contralateral red nucleus. Both of these then send out descend motor control, again to contralateral from them.
Describe vestibulocerebellar paths
1) vestibular nerve sends fibers to flocculonodular lobe AND VERMIS. SOME of them go by way of the vestibular nucleus
2) Flocculonodular node sends fibers to Vestibular nucleus, some by way of the fastigial nucleus.
3) fastigial nucleus sends fibers to Reticulospinal tract
4) vestibular nucleus sends fibers to Lat and Med Vestibulospinal tracts. (MVST joins with MLF)
By which cerebellar peduncle to afferents from the vestibulocerebellar path enter?
ICP
(remember, some CN VIII fibers go straight to flocculonodulra node. some go by way of vestibular nucleus.

in any event, everything at this point is ipsilateral)
More on vestibulocerebellar output pathway
1) Efferents leave flocculonodular node thru the ICP!!!!
2) Some go straight to vestibular nucleus, and then descend thru vestibulospinal tract (some also ascend via MLF'
3) Some go to fastigial nucleus
4) from fastigial, there is BILATERAL input to vestibular nucleus, from where they descend
5) there is also input to the midline RETICULAR FORMATION, from where fibers descend in the reticulospinal tract
name a result of damamge to ICP
intention tremor
(youo are losing output to cerebral motor cortex)
Name result of damage to MCP
gait ataxia
If you damage pontine nucleus on one side, on which side is the pathology: same or contral
contralateral
(goes from pointine nuc to contral cerebellum via MCP, purkinjes go to Dentate, leaves via SCP, goes to contral motor cortesx and red nuc, to CONTrA (cross back again) body
Name deficit from ICP lesion?
ataxia (Hit the dorsal spinocerebellar tract coming in from spine into SCP)

Also hit inferior olive climbing fibers: deficit in adapting to changing environment

nystagmus: hit input and output to vestibular nuclei
What is the general funcion of the inferior olivary nucleus
adaptation to changing environment

receives inptu fromm cortex, red nucleus, spinal cord

sends climbing fibers to cerebellum via CONTRALATERAL ICP

climbing fibers: 1:1 fiber:purkinje:deep nucleus ratio
what damage do you associate with ataxia?
damage to any of the three peduncle paths
what damage do you associate with nystagmus?
damage to vestibulocerebellar path
what damage do you associate with intention tremor?
dorsal spinocerebellar tract (DSCT-limb movement refinement) and any descending pathways
what are the exceptions to ipsilateral deficit/lesion pattern in cerebellar tracts?
Pontine nucleus damage-->contralateral dficit

Inferior olivary nucleus damage --> contralateral deficit
which CN are all sensory?
1, 2, 7
Which CN are all motor
3, 4, 6, 11, 12
which CN are mixed motor/sensoryq
5, 7, 9, 10
Where does spinal trigem nuc get input from
V: sensation from face and cornea and anterior 2/3 tongue

IX: sensation from posterior 1/3 tongue

VII, IX, X: sensation from ear

V, X: senation from meninges
What nerves input to spinal trigem nuc
V, VII, IX, X
whhy is corneal reflex bilateral?
Because sensation carried by V afferents back to nuc of 5 the projects bilaterally from 5 nuc to the facial nuclei
what sensations does solitary nucleus get?
TASTE (special sensation) from ant. tongue (VII) and posterior tongue (IX) and epiglottis (X)

VISCERAL SENSATION: from pharyx (IX, X), carotid body/sinus (IX), larnyx (X), thorax and abdomen (X)
In sum, which nerves send fibers to solitary nucleus?
VII, IX, X
What does nucleus ambiguus do? Via which CN?
Motor to pharynx/larynx
IX, X, XI
Describe gag reflex?
Sensory input from IX to the solitary nucleus.

Motor output via nucleus ambiguus (IX, X, XI)
What does dorsal vagal motor nucleus do?
sends X parasymp preganglionics to gut, lung, heart
name four output directions from the vestibular nucleus
1) to cerebellum via ICP
2) to EOM rostrally via MLF
3) to cortex (?) via VP of thalamus
4) to vestibulospinal tract
describe voluntary and involuntary control of lateral gaze
VOLUNTARY
1) FEF to contralateral PPRF
2) PPRF to nuc VI
3) Nuc VI to ipsilateral LR and (via MLF) contralateral nuc III.
4) nuc III to that side's MR

INVOLUNTARY
1) vestibular nucleus BILATERALLY to both nuc VI
2) Each nuc VI to its side's LR and (Via MLF) contralateral nuc III-->MR.
what is the dorsal cochlear nucleus involved in?
sound identification
Describe the auditory path
1) cochlear nerve to cochlear nucleus (dorsal and ventral)
2) Dorsal cochlear nucleus to CONTRAlateral Lateral lemniscus nuclues, then up to that side's inferior colliculus --> medial geniculate --> primary auditory cortex

3) Ventral cochlear nucleus to BOTH SON complexes, which project to their sides' lateral lemniscus nucleus, inferior colliculus, Medial geniculate body, primary auditory cortex.
function of ventral cochlear nucleus
sound localization
Functions of SON
MEDIAL: compares timing of inputs to each ear
LATERAL: compares intensity of inputs to each ear
Which bodies are tonotopically organized?
nuc of lateral lemniscus
inferior colliculus
medial geniculate body
primary auditory cortex

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