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Block 5 Week 2 Dani > Von Bartheld- Vision II > Flashcards

Von Bartheld- Vision II Flashcards

1
Q

What is considered the “gateway to the cortex”?

A

lateral geniculate nucleus

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2
Q

What are the four CNS targets of retinal ganglion cells?

A

lateral geniculate nucleus (LGN)
pretectum
hypothalamus
superior colliculus

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3
Q

Why would retinal ganglion cells want to target the pretectum?

A

for the pupillary light reflex

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4
Q

Why would retinal ganglion cells want to target the hypothalamus?

A

for circadian rhythm

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5
Q

Why would retinal ganglion cells want to target the superior colliculus?

A

visual reflexes; eye and head movements

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6
Q

What is the major target of ganglion cell axons in the optic tract in the diencephalon?

A

the dorsal lateral geniculate nucleus of the thalamus

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7
Q

How do neurons of the dorsal lateral geniculate nucleus of the thalamus send their axons to the cerebral cortex?

A

via a part of the internal capsule called the optic radiation and then terminates in the primary visual cortex (V1) or striate cortex of the calcarine fissure in the occipital lobe

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8
Q

What happens if you damage your retinogeniculostriate pathway (primary visual pathway)?

A

serious visual impairment

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9
Q

What does the edinger wesphal nucleus carry?

A

preganglionic parasympathetics

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10
Q

Explain how you get constriction of pupils?

A

light->bilateral projections from retina go to pretectum (b/w thalamus and midbrain). Pretectal neurons project to edinger westphal nucleus in the midbrain->sends its parasympathetic preganglionics to ocuolomotor nerve (CN 3) to terminate on neurons in ciliary ganglion. Neurons of ciliary ganglion innervate the constrictor muscles of the iris which decreases diameter of pupil when activated….. SO when you shine a light in someones eye it constricts!

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11
Q

Why do you get bilateral constriction of pupils when you shine a light in someones eyes?

A

because your pretectal neurons send axons to BOTH Edinger westphal nuclei!

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12
Q

Where is the suprachiasmatic nucleus located and what does it do?

A

Base of diencephalon, circcadian rhythm

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13
Q

Where is the superior colliculus and what does it do?

A

midbrain, coordinates head and eye movements

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14
Q

Explain sympathetic control of pupil dilation

A

retina tells pretectum which tells the superior cervical ganglion to send postganglionc sympathetics up the internal carotid and into the short and long ciliary nerves to innervates dilator pupillae muscle

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15
Q

projections to the lateral geniculate nucleus arise from ganglion cells who specialize mediating what?

A

richness of visual perception (high acuity, color, motion)

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16
Q

Projections to the hypothalamus and prectum arise from ganglion cells that are only suited for detecting (blank)

A

luminance flux

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17
Q

Following damage of the visual cortex or lesions of the pathways to the visual cortex what will remain? what has been said to be associated with this?

A

the subcortical pathway

Blindsight!

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18
Q

What is blindsight?

A

it is when you cannot see because your visual cortex is damaged or you have a broken visual pathway BUT when given a visual stimuli, patients can guess what it is!!!

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19
Q

What is the binocular visual field?

A

FP until before peripheral vision

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20
Q

Mixing of the pathways (right and left eyes) does not happen until the level of the (blank). Are the fibers mixed at the LGN?

A

visual cortex

NO

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21
Q

Explain to me what binocular disparities are

A

each eye sees an object at a slightly different angle and are constantly compensating to make their focus equal. The disparities are interpreted as differences in depth and are fused.

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22
Q

What is this:
the perception of depth produced by the reception in the brain of visual stimuli from both eyes in combination; binocular vision.

A

stereopsis

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23
Q

Explain the course of the optic radiation to the visual (striate) cortex

A

axons carrying info about superior portion of visual field sweep around the lateal horn of ventricle in the temporal lobe (meyers loop) before reaching the occipital lobe. Those carring inferior portion of the visual field travel in the parietal lobe
I.e inferior retinal quadrants give you superior visual field.
superior retinal quadrants give you inferior visual field

24
Q

Tell me about the fovea and retinotopy

A

the fovea comprises one of the smallest areas of retinal surface area but makes up half the visual cortex.

25
Q

V1 is the primary visual cortex. What are the secondary (extrastriate cortices) cortices?

A

V2, V3, V4, VP, MT

26
Q

Is there only one retinotopic map?

A

no there are many

27
Q

Crossing of nasal retinal ganglion cell axons in the chiasm do what?

A

Projects the right visual field to the left side of the brain and the left visual field to the right side of the brain

28
Q

Several circular retinal ganglion cell receptive fields combine to form (blank) on individual neurons in cortex.

A

elongated fields

29
Q

How do we get a singular complete image to the cortex?

A

rods and cons create an image and send it to the retina which will send affarent fibers to synapse in the LGN which will go to the cortex which will create a simple field that unifies all the info

30
Q

Where do you find the lateral geniculate nucleus (gate keeper for vision)?

A

thalamus

31
Q

Neurons in visual cortex respond to distinct stimulus (blank). So what does this mean?

A

orientation

Means you will be able to process visual information coming at you from all different angles

32
Q

Neurons in your visual cortex respond greatest to what orientation?

A

edges and light and dark

33
Q

The complexity of a response increases as you move closer to the (blank).
SO.. which cells will have the simplest response? Which will have the most complex?

A

visual cortex
ganglion
hypercomplex

34
Q

The simple cells of the visual system (such as ganglion and geniculate) will see what kind of stuff? what about more complex cells?

A

circles/dots (blurry)

bars, edges (sharp)

35
Q

The complex cells of the visual system are sensitive to what?

A

movement, binocular vision, sharp edges, orientation

36
Q

There are distinct pathways of specific retinal ganglion cell types that travel through the (blank) to the visual cortex.

A

LGN

37
Q

There are distinct pathways of specific retinal ganglion cell types that travel through the LGN to the visual cortex. What are these three ganglion/ pathways?

A

Parvocellular
Magnocellular
Koniocellular

38
Q

What does the parvocellular nuclei provide?

A

spatial acuity and color

39
Q

What does the magnocellular nuclei provide?

A

rapid motion

40
Q

What does the konicellular nuclei provide?

A

short wave length cones (Blue light) !

41
Q

Right eye and left eye go to different (blank) within the visual cortex. Also you have what 2 other kinds of columns? In level four do you still have separate columns for the eyes or are the inputs still segregated?

A

columns
ipsilateral and contralateral
still segrated

42
Q

The contralateral and ipsilateral eye columns go to separates spots in layer 4 so you have what kind of vision of layer four?

A

4

mononoculear

43
Q

What is signif about layer 4?

A

you will for the first time ever, have both the right and left fibers in the same layer

44
Q

When do you get binocular vision?

A

when you leave 4

45
Q

Large visual defects are called (blank)

A

anopsias

46
Q

Smaller visual field deficits are called (blank)

A

scotomas

47
Q

What do you call it if you lose your peripheral vision?

A

bitemporal (heteronomous) hemianopsia

48
Q

What do you call it if you lose your left temporal and your right nasal field?

A

left homonomous hemianopsia

49
Q

What do you call it if you lose your left temporal superior and your right nasal superior?

A

left superior quadrantanopsia

50
Q

What do you call it when call it if you lose both the left temporal and the right nasal field but still have your macula?

A

Left homonomous hemianopsia with macular sparing

51
Q

What is maculopathy?

A

when you have a small black dot in the center

52
Q

What does it look like if you retinitis pigmentosa?

A

like you have a dark border around what you see

53
Q

What are 2 visual field testing techniques?

A

confrontation field testing (finger testing in each quadrant)
computerized plotting

54
Q

Where do you have blind spots in your eye?

A

at the optic disc!

55
Q

How do you remember the vision pathway for paraysmpathetics?

A

PREPE (preppy) Eddy is cilly “looking i.e for the visual pathway”
prectectum-> edinger westphal nucleus->pregangionic sympathetics -> CN3 -> ciliary -> constricter muscles

Block 5 Week 2 Dani (10 decks)

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