Neuro.block 3 Visual

Front 1

Beyond the immediate area of the circle of Willis, the optic tract is usually supplied by the the _

Back 1

anterior choroidal artery.

Front 2

The lateral geniculate nucleus itself is primarily supplied by the _, a branch of the posterior cerebral artery.

Back 2

lateral posterior choroidal artery

Front 3

The optic radiation or geniculocalcarine tract project between the _ and _

Back 3

lateral geniculate nucleus and primary visual cortex

Front 4

The projection for the upper half of the visual field is called _, it travels forward and over the _.

The lower half of the visual field projection goes directly _, over the _

Back 4

Meyer's loop, the inferior horn of the lateral ventricle.

directly posteriorly over the atrium of the lateral ventricle.

Front 5

Meyer's loop projections are subject to lesions of what artery?

Those more medially placed fibers are sensitive to lesions of what artery?

Back 5

Middle cerebral artery

Posterior Cerebral artery

Front 6

Beyond the geniculocalcarine tract, most of visual cortex is supplied by the _ artery

Back 6

posterior cerebral artery.

Front 7

Localized damage in the retina can produce visual field deficits that are _

Back 7

inverted and switched left to right.

Front 8

Glaucoma typically arises from disruption of the __

Back 8

production or drainage of aqueous humor in the anterior chamber, and may result in increased intraocular pressure.

This pressure is transferred to the back of they eye where the optic disc is sensitive to damage

Front 9

Retinal separation occurs between the _ and _, typically at the periphery of the retina.

Back 9

pigment epithelium and photoreceptor layer

Front 10

Retinal detachment is perceived as _, _ and _ in one eye.

Back 10

bright flashes, increases in floating bodies, and a partial loss of vision,

Front 11

The _ is the region of highest visual acuity

Back 11

fovea

Front 12

_ form is the most common type of macular degeneration.

Back 12

dry form.

may be due to hereditary factors, cardiovascular disease, light exposure, and nutritional causes

Front 13

Transient blindness on the affected side that is seen as a window shade going down over the eye describes what condition?

Back 13

amaurosis fugax

Front 14

The right half of the visual field in (right,left,each) eye gets routed to the left hemisphere

Back 14

each

And the left half of the visual field in each eye gets routed to the right.

Front 15

Visual deficits in both eyes suggest...

Back 15

a lesion of the visual system either in the optic chiasm or beyond it toward the CNS.

*A possible exception is very proximal lesions of the optic nerve can involve optic nerve axons from the chiasm that arise from nasal retina of the contralateral eye.

Front 16

Lesions of the center of the optic chiasm disrupt the axons crossing from the _
This produces (bilateral/ipsilateral/contralateral) deficits in the _ visual field or _

Back 16

nasal retina.

bilateral

temporal

bitemporal hemianopia

Front 17

A lesion of the _ artery, affecting the optic tract produces homonymous hemianopia, which is where axons from the _retina of the contralateral eye and the _ retina of the ipsilateral eye are interrupted

Back 17

anterior choroid artery

nasal from the contralateral

temporal from the ipsilateral

Front 18

The inferior visual field projects to the _ retina, and the _ bank (of the calcarine sulcus).

Back 18

superior retina and superior bank

this is opposite for superior visual field

Front 19

Lesions of meyer's loop, with is the most common visual complication of _ artery strokes, produces _

Back 19

middle cerebral artery;

superior homonymous quadrantanopia

Front 20

Lesions that include primary visual cortex will produce _

Back 20

contralateral hemianopsia with macular sparing.

Front 21

With homonymous hemianopia, the closer the defect is to the chiasm the more _the left and right visual fields maps will be; the more posterior the lesion (toward occipital lobe) the more _the visual field defect.

Back 21

dissimilar , congruous

Front 22

TheThe eye consists of 2 fluid filled chambers, the area in front of the lens, that is filled with _and a chamber behind the lens, that is filled with _

Back 22

aqueous humor

vitreous humor

Front 23

Regarding lens accomodation, the lens becomes more _ shaped when viewing an object that is close than 20 ft, this action is achieved by the _ muscle.

The loss of the accomodation reflex with age is called _

Back 23

round

ciliary

presbyopia

Front 24

If the eye is too short (or squat), it results in _.

If the eye is too oblong, it results in _

Back 24

hyperopia, or far sightedness

myopia, or near-sightedness

Front 25

The inner layer of the eyeball is the _. This is where light is absorbed and transduced into an electrical signal

Back 25

retina

Front 26

Transduction is accomplished by photoreceptors on the _ layer of the eye.

Back 26

most posterior

Front 27

Rods are sensitive to _, and are located in the _ region of the retina. Rods contain photo-pigment containing _.

Back 27

dim light (night vision, scotopic vision) - they can not differentiate color.

Located in the non foveal region of the retina, and contain rhodopsin (Vit A)

Front 28

Cones or rods are more sensitive to light

Cones or rods are more prevalent in the eye

Back 28

rods

rods

Front 29

Cones are mostly found in the _ region

Back 29

foveal

The fovea is the region of the eye with the highest visual acuity

Front 30

At the center of the fovea is the _, a 100 um wide area with specialized cones called _ and corresponding bipolar cells and ganglion cells

Back 30

foveola; midget cones

Front 31

Cones have different pigments, _ which are sensitive to different frequencies of light.

Back 31

iodopsins,

Front 32

In the dark, rods are depolarized to -40mV, and they release _ to 2nd order cells

Back 32

glutamate

Front 33

Under illumination, when photoreceptor glutamate ↓, on-bipolar cells are _

Back 33

disinhibited.

Front 34

Horizontal cells are (inhibitory/excitatory)

Back 34

inhibitory...they release GABA

Front 35

If the subject is in the dark, half the bipolar cells will be firing vigorously, those are the (on/off)center, (on/off) surround

Back 35

Off center, on surround

Front 36

Lateral inhibition mediated by horizontal cells is part of the mechanism responsible for _

Back 36

Mach lines (seeing the edge in light vs dark)

Front 37

_ and _ cells synapse on ganglion cells.

Back 37

Bipolar and amacrine cells

Front 38

_ cells are the only retinal cells that have voltage gated sodium channels, and the only cell type that generates action potentials.

Back 38

Retinal ganglion

Front 39

Largest RGC population are the _ cells

Back 39

alpha cells (physiologic Y or M)

they receive Input from peripheral rods. I.e. involved in scotopic vision
they are Large cells with large receptive fields

Front 40

beta RGC have input from _, _ receptive fields, and are used for _ vision

Back 40

cones; small; high resolution vision

Front 41

Retinal ganglion cell axons within the retina are unmyelinated until they pass through the _, after which they become myelinated in the optic nerve

Back 41

sclera

Front 42

Retinal ganglion cells primarily contact the _ of the thalamus

Back 42

lateral geniculate nucleus of the thalamus

Front 43

Layers 1 & 2 of the lateral geniculate are called the _ layers, receive input from _ type RGCs with receptive fields that receive input primarily from _ .

Back 43

magnocellular
large alpha (Y)
rods

Front 44

Layers 3-6 (aka _ ) receive input from _type RGCs with receptive fields that receive input from _and process _

Back 44

parvocellular layers;
smaller, beta (X)
cones
high acuity color visions.

Front 45

As part of the distribution of visual fields, axons in the temporal retina are distributed to the (ipsilateral/contralateral) lateral geniculate nucleus in layers _,_, and _

Back 45

ipsilateral

2, 3, and 5.

Front 46

As part of the distribution of visual fields, axons in the nasal retina are distributed to the (ipsilateral/contralateral) lateral geniculate on layers _,_ and _

Back 46

contralateral

1, 4, and 6.

Front 47

The neurons of the lateral geniculate project to the ipsilateral visual cortex as a bundle of axons, the _

Back 47

optic radiations (geniculocalcarine tract).

Front 48

The optic radiations have two primary bundles: one that projects to the _and the other, Meyer’s Loop, going to the _

Back 48

superior bank of the calcarine sulcus,

inferior bank of the calcarine sulcus

Front 49

Meyer's loop runs downward and backward over the _ on it's way to the inferior bank of the calcarine sulcus. The inferior banks represent the (superior/inferior) visual fields

Back 49

lateral ventricle

superior

Front 50

Regarding the retinotopic map; Peripheral fields are located _, Central vision -the macula and fovea –are represented more _

Back 50

rostrally

caudally toward the occipital pole.

Front 51

Due to a white band called the band of Gennari, primary visual cortex is referred to as _

Back 51

Striate cortex.

Front 52

Regarding the retinotopic map of the LGN, peripheral fields are located _, while central vision (macula and fovea) is represented _

Back 52

rostrally

caudally

Front 53

There are blob zones dispersed within the ocular dominance and orientation columns that process only _. These are prominent in what layers?

Back 53

color information.

layers II and III (Not IV)

Front 54

The M stream arises from the _ areas of the LGN, carrying information from RGCs with _ receptive fields. The route for this stream is...

Back 54

magnocellular areas; large receptive fields.

V3 sub region of 18 -> middle temporal area (MT V5) -> Posterior parietal (7a)

Front 55

_ appears responsible for processing “where” objects are in the visual field, including position, motion, to some extent depth, and other spatial information.

Back 55

Magnocellular stream

Front 56

The P stream receives information from the _ areas of the LGN, it is the "_" stream, and processes _ and _

Back 56

Parvocellular
"what"
color and shape

Front 57

The pathway for the P stream is...

Back 57

Outputs from V2 to V4 subregion of area 19, to the inferior temporal region, and then areas 20, 21, and 37

Front 58

The _ is primarily involved in depth perception.

Back 58

parvocelluar stream