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Neuroscience > visual motor systems > Flashcards

visual motor systems Flashcards

1
Q

frontal eye field is a

A

PRE-MOTOR area, and is brodman areas 6 and 8 (depends on textbook)

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2
Q

frontal eye fields receive target location from__ and project to___

A
  • visual association cortex

- project to horizontal and vertical gaze centers of superior colliculus

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3
Q

3 types of eye movemtnts that direct targets to the fovea?

A
  • SACCADES=> rapid mvmt toward new targets (conjugate)
  • SMOOTH PURSUIT=>slower mvmts that follow moving targets (conjugate)
  • VERGENCE=> mvmts that adjust the eyes toward near and far objects (disconjugate)
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4
Q

vestibulo-ocular reflex fxn

A

compensate for ACCELLERATION

aka–to keep things on your fovea –“foveation”

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5
Q

optokinetic reflex fxn

A

compensates for mvmt of the entire visual field

aka–holds images STEADY during sustained head rotation

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6
Q

pupillary light reflex fxn

A

maintains retinal illumination (4 neuron chain with ciliary ganglion and SHORT ciliary nerves)

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7
Q

blink reflex fxn

A

protects the eye

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8
Q

M1 (area 4)

A

random mvmts

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9
Q

SM (area 6)

A

planned mvmts

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10
Q

nuclei in the pons that have to do with visual system

A
  • PPRF,
  • abducens,
  • MLF
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11
Q

nuclei in the midbrain that have to do with the visual system

A
  • MLF,
  • occulomotor nucleus,
  • trochlear nucleus,
  • nuclei of Cajal and riMLF (vertical eye mvmts)
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12
Q

two kinds of eye movement pathways

A
  • nuclear and infranuclear pathways ==> brainstem nuclei and peripheral parts of CNIII, IV, VI
  • supranuclear pathways ==> brainstem and forebrain circuits
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13
Q

what are frontal eye fields for in eye movements

A
  • remembered movements,
  • scanning for areas of interest
  • suppressing uninteresting things
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14
Q

superior colliculus involvement in eye movements

A
  • reflexive ORIENTATING. this spot has a map of your visual field so that if you see something interesting, your eye can accurately direct the fovea to that location
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15
Q

what are the only two muscles that do NOT pull the eye at a WEIRD angle

A
  • lateral rectus

- medial rectus

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16
Q

what muscles and CN do you use for STRAIGHT and UPWARD gaze

A
  • superior oblique (CN IV)

- superior rectus (CN III)

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17
Q

Hering’s law

A

during conjugate eye mvmts, the YOKED muscle pair receives EQUAL innervation so the eyes move TOGETHER

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18
Q

course of CNIII

A
  • lateral wall of cavernous sinus (topmost nerve)
  • receives nn from carotid plexus and V1
  • enters s. orbital fissure THRU annulus
  • DIVIDES to sup. and inf.
19
Q

course of CNIV

A
  • lateral wall of cavernous sinus below CNIII
  • crosses III, enters s. orbital fissure THRU annulus
  • has communications with CAVERNOUS plexus and V1
20
Q

course of abducens nerve

A
  • WITHIN cavernous sinus, lateral and inferior to ICA
  • enters s. orbital fissure THRU annulus
  • has communications with CAVERNOUS plexus and V1
21
Q

horizontal gaze center

A

frontal eye fields and superior colliculus.

BUT. thats NOT the only function of these two things. they can do all the mvmts

22
Q

three kinds of neurons in PPRF

A

excitatory burst => to abducens nucleus
inhibitory burst => to other abducens nucleus
omnipause neurons => allow your eyes to pause

23
Q

visual deficit if you have demeylination in ventral pons

A

ipsilateral abducens nerve palsy

24
Q

superior tarsal muscle
Innervation?
syndrome?

A

sypathetic fibers
horners syndrome. if the lesion is in the spinal cord or the superiro cervical ganglion, its full blown. if its after the ganglion, you ususally don’t have anhydrosis

25
Q

internuclear neurons

A

for CONJUGATE eye movement for MLF

26
Q

lesion of R abducens NERVE

A

R abducens nerve palsy. (ONLY R eye can’t look R)

27
Q

lesion of R abducens NUCLEAR lesion

A

R lateral gaze palsy (the nucleus projects to TWO places, so NEITHER eye can go R)

28
Q

lesion of R PPRF

A

PPRF is abducens nucleus. R lateral gaze palsy

29
Q

lesion of L MLF

A

L internuclear ophthalmoplegia (can look L, but when you look R, the R eye gets nystagmus, and L eye can’t do it)
affects VI and contralateral III

30
Q

lesion of L MLF plus the L abducens nucleus

A

you wipe out 1 and a half eye movements. “one and a half syndrome” (you can only look R in the R eye, but you get nystagmus in it)

31
Q

vertical gaze centers

A

midbrain, close to occulomotor nucleus (riMLF and Cajal)

32
Q

what parts of cerebellum are involved in these eye movements

A

fastigial nucleus, flocculus

33
Q

if you have a pineal tumor, it presses on DORSAL MIDBRAIN. what will you see? (haha or not see)

A
  • impaired vertical gaze
  • large irregular pupils that don’t respond to light
  • eyelid abnormalities
  • impaired convergence
34
Q

frontal eye fields project to?

A
  • horizontal gaze center,
  • superior colliculus
  • vertical gaze center
35
Q

superior colliculus UPPER layer info

A

input from the visual system for visual space

aka “WHERE is the info coming from”

36
Q

superior colliculus LOWER layers

A

receive info FROM upper layers. the lower part does the MOTOR movements, and project to GAZE centers

37
Q

smooth pursuit firing pattern?

A

its GRADED. aka you do NOT have bursts. its GRADUAL

38
Q

smooth pursuit input from?

A

CBellum more than superior colliculus

**remember that vestibuloCBellum goes thru juxtarestofirm body to vestibular nuclei and then to the motor nuclei

39
Q

NEAR response triad?

A
  • eyes CONVERGE via action of medial recti
  • lens ROUNDS UP increasing refractive power
  • pupil CONSTRICTS (meiosis)
40
Q

where does VERGENCE come from

A

MIDBRAIN!!!

  • supraoculomotor area (SOA)
  • not well known, but it obviously has to involve CNIII
41
Q

occulomotor channel

A

supplementary eye fields

  • VA,
  • MD
42
Q

lesion of parietal cortex affecting vision

A

related to SPATIAL information

  • problems with where stream… SUPRAMARGINAL and ANGULAR gyri
  • problems with saccades
  • problems reaching for things in space
  • “Simultagnosia” problems multitasking eye objects
43
Q

what do NBME exams like to do

A

put in stupid charts of nerve impulses for things like nystgmus

44
Q

always remember what about nystagmus

A

ALWAYS named for the FAST phase

Neuroscience (23 decks)

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