Week 3- Brainstem Systems

Question 1

The inability to voluntarily look R or L with a preserved ability to tract an object in an H test suggests what…

Answer 1

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

Question 2

ptosis from CN III palsy is due to inactivation of ______ which means ______ is unopposed

Answer 2

levator palpebrae superiosis

orbicularis oculi

Question 3

The superior oblique is innervated by the ipsilateral or the contralateral trochlear nucleus? What about the lateral rectus?

Answer 3

IV is contralateral

VI ipsilateral

Question 4

Features of tuberculous meningitis…

Answer 4

exudate in the subarachnoid space

hydrocephalus

cerebral edema

arteritis

NOT intranuclear inclusions

Question 5

what infxn would you see perivascular lymphocytic cuffing?

Answer 5

rabies…NOT prion disease

Question 6

What is the action of the superior oblique

Answer 6

depresses an adducted eye

intorts an abducted eye

Question 7

Damage to which cranial nerves could produce diplopia?

Answer 7

III, IV, VI

Question 8

Does a positive romberg indicate dorsal column problems or cerebellar problems?

Answer 8

Dorsal column. A person with cerebellar deficits will sway regardless of whether their eyes are open or not.

Question 9

Do oligodendrocyte process envelope both myelinate and unmyelinated nerve processes?

Answer 9

NOPPPPPE. Only one of them, according to the quiz.

But schwann cells do both

Question 10

The abducens nucleus in the floor of which ventricle?

Answer 10

The 4th….

Question 11

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?

Answer 11

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

Question 12

Where are the vestibular nuclei?

Answer 12

In the pons

Question 13

Contraction of the ciliary muscles does what to the lens?

Answer 13

allows it round

Question 14

What is the uvea?

Answer 14

the uvea is the pigmented layer of the eye

iris

ciliary body

choroid

Question 15

Photodetection association with (increased/decreased) cGMP?

Answer 15

decreased

Question 16

What does lateral inhibition in the retina create?

Answer 16

centre-surround receptive field effect. Created by amacrine

Question 17

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

Answer 17

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

Question 18

In addition to the LGN, where else does optic information go?

Answer 18

• superchiasmatic nucleus (sleep/wake) (anterior hypothalamus)
• pretectal nuclei in midbrain (pupil reflex)

Question 19

Is being diagnosed at <40 y.o suggestive of a more or less favorable outcome than being diagnosed at an older age?

Answer 19

More…because your more likely to have relapsing-remitting MS than if you are diagnosed when you’re older. Being female is also better

Question 20

What are the dorsal and ventral pathways for?

Answer 20

Dorsal “where”: motion perception, saccadic targeting (makes sense because the parito-occipital is responsible for saccades)

Ventral: “what”, color, form, object, face

Question 21

3 types of volitional saccades? How is the path for volition and reflexive saccades different?

Answer 21

memory

predictive

antisaccade

Reflexive goes through the superior colliculus

Question 22

What is the name of the centre that controls accomodation?

Answer 22

Supraoculomotor area (rostral midbrain)

PPRF: saccades

vertical gaze centre (in pretectal area)

Question 23

Would you see diplopia with a supranuclear lesion?

Answer 23

No!

Question 24

What is the difference between saccades and pursuit?

Answer 24

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

Question 25

What type of agent causes: brain abscess, empyema, meningitis, encephalitis, septic thrombophlebitis?