Week 3- Brainstem Systems Flashcards
The inability to voluntarily look R or L with a preserved ability to tract an object in an H test suggests what…
Something is wrong with the FEFs
Parieto-occipital controls pursuit and does not involve PPRF, FEFs control saccades
MLF deficits would have problems in voluntrary and pursuit movements
ptosis from CN III palsy is due to inactivation of ______ which means ______ is unopposed
levator palpebrae superiosis
orbicularis oculi
The superior oblique is innervated by the ipsilateral or the contralateral trochlear nucleus? What about the lateral rectus?
IV is contralateral
VI ipsilateral
Features of tuberculous meningitis…
exudate in the subarachnoid space
hydrocephalus
cerebral edema
arteritis
NOT intranuclear inclusions
what infxn would you see perivascular lymphocytic cuffing?
rabies…NOT prion disease
What is the action of the superior oblique
depresses an adducted eye
intorts an abducted eye
Damage to which cranial nerves could produce diplopia?
III, IV, VI
Does a positive romberg indicate dorsal column problems or cerebellar problems?
Dorsal column. A person with cerebellar deficits will sway regardless of whether their eyes are open or not.
Do oligodendrocyte process envelope both myelinate and unmyelinated nerve processes?
NOPPPPPE. Only one of them, according to the quiz.
But schwann cells do both
The abducens nucleus in the floor of which ventricle?
The 4th….
What do the semi-circular canals and the saccule and utricle sense? What are the sensory bodies of each? Is the impulse a depolarization or a hyperpolarization?
SCC: angular accelaration, cristae ampullae
utricule/saccule: linear acceleration, macula
depolarization, but note that there is a resting discharge that is enhanced with bending of the kinocilia
Where are the vestibular nuclei?
In the pons
Contraction of the ciliary muscles does what to the lens?
allows it round
What is the uvea?
the uvea is the pigmented layer of the eye
iris
ciliary body
choroid
Photodetection association with (increased/decreased) cGMP?
decreased
What does lateral inhibition in the retina create?
centre-surround receptive field effect. Created by amacrine
What are the two types of cells in the retinal ganglion? How do they compare in terms of receptive field, spatial resolution? What is color opponency
Magnocellular: lg field, low resolution
Parvocellular: small field, high resolution, color opponency
Color opponency is when the parvocellular neuron compares the different signals it gets from cones to determine what the color actually is
In addition to the LGN, where else does optic information go?
- superchiasmatic nucleus (sleep/wake) (anterior hypothalamus)
- pretectal nuclei in midbrain (pupil reflex)
Is being diagnosed at <40 y.o suggestive of a more or less favorable outcome than being diagnosed at an older age?
More…because your more likely to have relapsing-remitting MS than if you are diagnosed when you’re older. Being female is also better
What are the dorsal and ventral pathways for?
Dorsal “where”: motion perception, saccadic targeting (makes sense because the parito-occipital is responsible for saccades)
Ventral: “what”, color, form, object, face
3 types of volitional saccades? How is the path for volition and reflexive saccades different?
memory
predictive
antisaccade
Reflexive goes through the superior colliculus
What is the name of the centre that controls accomodation?
Supraoculomotor area (rostral midbrain)
PPRF: saccades
vertical gaze centre (in pretectal area)
Would you see diplopia with a supranuclear lesion?
No!
What is the difference between saccades and pursuit?
pursuit allows us to follow slowly moving objects and is initiate in the parieto-occipital region. saccades allow us to follow quickly moving objects and is initiated in the FEFs and goes through the PPRF
What type of agent causes: brain abscess, empyema, meningitis, encephalitis, septic thrombophlebitis?
