Color Vision Exam 1

Where are S cones located?

0.5 degrees from foveal center, form ring around fovea

What is the prevalence of protanomaly? Inheritance?

1% men and 0.03% women, x linked

What the term for a person who only has rods? What do they see?

Achromat or rod , grey

What is the term used for a patient who is truly color blind?

Achromat or rod monochromat

What law states that if equal radiation (hue) is added to both sides of a metameric color match, they will match?

Additive Grassman's Law of Metamers

What are the three Grassman's Laws of Metamers?

Additive Scalar, Associative

In opponent theory, which cones are fed into brightness sensation?

All 3 types!

What is saturation discrimination?

Amount of wavelength you can add to white before being able to discriminate that it's not white

Which mode of color is referring to the color perceived not being associated with an object but due to paths of light scatter? Example: sky

Aperture color

What law states that if 2 color are a metameric match, they can be used interchangeably in a color match?

Associative Grassman's Law of Metamers

What is the inheritance of tritanopia? What is the prevalence in men? Women?

Autosomal dominant, 1:13,000 men=women

In the opponent theory, what channel gives luminance (brightness)?

B-W

Is half toning (when talking about color printers) additive or subtractive?

BOTH actually

What is found int he koniocellular pathway found interposed between the 6 layers of the LGN?

BY color opponency, color and shape/form discrimination

What does the luminance function on a graph look like for a normal color individual? Deutan? Protan?

Bell shaped curve with max at 555nm Deutan slightly toward longer wavelengths Protan slightly toward shorter wavelengths

_______(Above/Below) the spectral locus represents all colors we can see.

Below

Red filter+green filter+white light....what is transmitted?

Black

What is in the center of CIE diagram based on color subtraction?

Black instead of white

When the B-Y opponent color channel is stimulated with short wavelengths, what color will be perceived?

Blue

What is the term used for a patient who only has rods and short wavelength cones functional? What do they see?

Blue cone monochromat They see blue and have normal night vision

What colors do tritanopes confuse?

Blue with blue/green and white with yellow

What is the color and pigment associated with short-wavelength sensitive cones?

Blue, cyanolabe

What is the attribute of light-source color by which emitted light is ordered continuously from light to dark in correlation with its intensity?

Brightness

What do McAdam's Ellipses demonstrate?

Each ellipse represents areas you wouldn't notice a hue or saturation difference- the larger the ellipse, the larger the discrimination threshold (AKA some wavelengths you can change slightly and notice-smaller ellipses-but some you have to change more to notice a difference- these would be the larger ellipses)

What behavior is the prefrontal cortex involved with?

Decision making

What signs and symptoms do rod monochromats and blue cone monochromats have?

Decreased VAs, photophobia, nystagmus, abnormal luminance function

On a CIE diagram, what does the triangle (gamut) denote?

Denotes colors made with a specific device like a computer screen or printer

In Trichromatic theory, absorption is ____________(dependent/independent) of wavelength, whereas neural effect is __________(dependent/independent) of wavelength.

Dependent, independent

When retinal BP cells are excited they are __________(hyperpolarized/depolarized).

Depolarized

For a color deficient individual (deutan and protan) which wavelengths appear less saturated (AKA where are their neutral points?)

Deutan- 498 Protan- 492

What is the term for a person missing middle wavelength cones?

Deuteranopia

What is the term for a person who only has 2 types of cones?

Dichromat

How can color constancy break down?

Difference in background color/perceptions

Are diffuse BP cells involved in color vision? What about cone BP cells?

Diffuse-no Cone-yes

Which mode of color is due to light distributing color onto an object?

Direct illumination

What type of neurons are in the striate cortex?

Double opponent neurons

What are the types of cells found in the primary visual cortex related to color vision?

Equiluminant cells and VI blob cells (VI interblob cells as well but not color sensitive)

What do equiluminant cells determine?

Equiluminant color gratings

What is another name for colorimetric purity?

Excitation purity

On a CIE diagram, if you mix unequal parts, how do you find your resultant wavelength?

Draw line connecting and resultant mixture is point closer to the wavelength with greater proportion

On a CIE diagram, if you mix equal parts, how do you find your resultant wavelength?

Draw line connecting the two- midpoint is answer

What is the term that means color deficient?

Dyschromatopsia

On a CIE diagram, how is saturation (colorimetric purity) quantified?

Excitation purity: a/a+b where a is distance to W and b is distance to spectral locus

Brightness is _________(independent/dependent) on due and saturation.

Independent

Two color with ientical wavelengths (monochromatic light)

Isomers

On a CIE diagram, what is the spectral locus and where is it located?

It is where colors are in purest form and located at the periphery of the graph

What does Abney's law state about luminance?

Its additive, there's a luminance channel only

What is known as the "relay station" in the visual pathway?

LGN

Parasol ganglion cells are involved in ________(large/small) receptive fields.

Large

Which layers of the LGN are dedicated to the magnocellular (luminance not color vision) visual pathway?

Layers 1 and 2

Which layers of the LGN are dedicated to the parvocellular visual pathway?

Layers 3-6

Are lighter or darker colors more likely to be a metameric match? Another way to ask this question: is it harder to detect between light or dark colors?

Light colors like taupe, mauve, lilac, tan, greys have a higher liklihood of metameric match

Name 3 examples of color addition

Light superimposition Pointillism TV/computer monitor

When referring to the Munsell Color System, what does value refer to?

Lightness/darkness- tube down the middle

What dichromats are missing long wavelength cones? What color can they not see? What colors will they confuse?

Protanope, cannot see red, will confuse R and G at wavelengths greater than 545nm

Which dichromats have the shortest visual spectrum?

Protanopes

Which dichromats should we worry about driving?

Protanopes and deuteranope

What is found in the parvocellular visual pathway in layers 3-6 of the LGN?

RG color opponency and maybe BY opponency as well

What is a yellow box on a computer monitor actually created by? What is this an example of?

Red and green pixels, color addition

What is the lilac chaser illusion? What does this demonstrate?

Red dots-->see cyan afterimage, this demonstrates a negative color

What is the Purkinje shift?

Red will look darker than blue in the dark to a dark adapted individual because cones are most sensitive at 555 and rods are most sensitive at 505- longer wavelengths are seen as darker

What is the color and pigment associated with long-wavelength sensitive cones?

Red, erythrolabe

What colors do protanopes and deuteranopes easily confuse?

Red, yellow and green Blue and purple

What are the three modes of color? Which is the most common?

Surface color (most common), aperture color, direct illumination

T or F: retinal ganglion cells are opponent cells?

TRUE

On a CIE diagram, how do you find the complementary color/wavelength?

Take a ruler and make a line from the point to the white and continue that toward toward the spectral locus on either side

On a CIE diagram, how do you find the dominant wavelength?

Take a ruler and make a line from the point to the white point then continue that line toward its spectral locus, intersection is the answer

What theory states that there are 3 things (PR) in the eye that help perceive colors?

Trichromatic theory

What are the two parts of the combined zone (stage) theory?

Trichromatic theory and opponent theory

What is the difference between areas of best color discrimination in dichromats vs trichromats?

Trichromats have 2 areas- 490 and 580, whereas dichromats only have 1 area protanopes: 495nm; deuteranopes: 502nm; Tritanopes: 570nm

What is the most rare dichromat?

Tritanopia

T or F: Although physically all wavelengths are equal energy, visual system perceives wavelengths at different energy levels.

True

T or F: Deuteranopes are similar to protanopes in that they both do not have wavelength discrimination above 545nm

True

T or F: Subjective complaints of color vision can not be used to diagnose protanopes because they are variable and similar to deuteranopes.

True

T or F: percent of light absorbed by photoreceptors varies with wavelength

True

T or F: LGN contains opponent neurons?

True **similar to RGCs

All primary colors for subtraction contain how many colors?

Two

Do we use 1931 or 1976 CIE diagrams?

Use 1931 even though 1976 is slightly more accurate

Where do VI color cells project to?

V2- thin stripes related to hue

What are the targets for konio LGN axons?

VI blob cells

What is the wavelength discrimination like in a patient who is an anomalous trichromat?

Variable- Y or U shaped

What is the prevalence of tritanomaly? Inheritance?

Very rare, very rare

Where does the LGN transfer its info?

Visual cortex

What does the wavelength discrimination graph look like?

W

How is hue quantified?

Wavelength

On a CIE diagram, what is represented at the spectral locus?

Wavelength

What three things does cone hyperpolarization depend on?

Wavelength of light, absorbance of PR, length of time of stimulation

What are the four physical properties of light?

Wavelength, chromatic/colorimetric purity, luminance, chromaticity

When referring to the Munsell Color System, what does hue refer to?

Wavelength- circuit around the "tube"

What is the basis of the Opponent theory?

We don't see R and G at the same time and don't see B and Y at the same time

Is the photopic luminance function different for an protanope? AKA do they perceive brightness differently?

Yes, significantly- peak luminosity at 540nm (555nm in color normals)

What law deals with perceived color of a surface?

Abney's Law of Additivity

What is the color confusion like for a protanomalous patient? Deuteranomous patient?

Abnormal color match- add excess red Abnormal color match- add excess green

Where are M and L cones concentrated? What is the ratio?

Foveal center, ratio of 1:1-1:16 for color normal

What does chromatic purity (saturation) mean?

Freedom from dilution with white

When is colorimetric purity=1?

If the spectral color is pure AKA no white added

In what retinal layer do the axons of retinal ganglion cells travel?

NFL

Does a tritanope's photopic luminance function differ from a color normal individual?

NO

Does chromaticness take brightness into account?

NO

Is Mie scattering wavelength dependent?

NO

Is the photopic luminance function significantly different for a deuteranope compared to a color normal individual?

NO, a little bit greater than 555nm

Do dichromats have reduced VAs?

No

Does each photoreceptor determine color?

No because majority of wavelengths cause more than 1 cone to be stimulated

Does opponent theory deal with color mixing?

No! This is a neural response, red and green are opponents and combine into intermediate channel which serves as the opponent channel for short wavelengths (yellow opposes blue)

What equation is used to quantify saturation (AKA colorimetric purity)?

P=L/L+Lw

Midget ganglion cells are involved in the _________(magnocellular/parvocellular) pathway.

Parvocellular

What pathway do VI blob cells process?

Parvocellular (color perception, color discrimination, learning/memory of color objects

Where is white represented on a CIE diagram?

Planckian locus- different standard illuminants in middle white area are connected by a line

What is the photopic luminance function like for a protanomalous patient?

Possible different, maybe 540

Does a tritanopes saturation differ front a color normal individual?

Pretty similar- 570nm will appear white

Midget ganglion cells are involved in _______ (large/small) receptive fields

Small

Retinal BP cells are arranged in an on-center/off-center pattern, what is this called?

Spatial antagonism

Where are double opponent neurons found?

Striate cortex (V1)(primary visual cortex)

Do color printers use color addition or subtraction?

Subtraction

Do paints use color subtraction or addition?

Subtraction

Do filters use color addition or subtraction? What is an example of this?

Subtraction, anaglyph glasses

Which mode of color is referring to an object absorbing or reflecting a certain wavelength? Example: an apple is red

Surface color

Yellow filter+cyan filter+white light...what is transmitted?

(Red+green)-(green+blue)=green

What is the ratio of PR:midget BP cell in the central retina? Why is this important?

1:1, this gives great detail (high resolution)

What is the prevalence of rod monochromacy? What is the inheritance?

1:30,000 Autosomal recessive

What percent of color deficient patients are unaware of their deficiency?

20-33%

What is the max absorption for short wavelengths?

420nm

Where do you need a negative amount of red?

450-550 region

Where are color normal individuals most sensitive? How many cone types are stimulated at each of these points?

490 (all 3 stimulated) and 580nm (2 types stimulated)

What are the most sensitive wavelengths? What does this mean?

490 and 580, this means that the smallest changes in wavelength will result in a noticeable color change

Where do protanopes have the best wavelength discrimination?

495nm

What is the prevalence of deuteranomaly? Inheritance?

5% men and 0.35% women, x linked

At what wavelength do deuteranopes have best discrimination?

502nm

What is the max absorption for medium wavelengths?

530nm

Protanopes have no discrimination above what wavelength

545- intensity based after that

Where is photopic at max? Scotopic?

550nm, 500nm

What is the cones luminosity peak?

555nm

What is the max absorption for long wavelengths?

560nm

What is a tritanopes best wavelength discrimination?

570nm

For a color normal individual, what wavelength looks less saturated (AKA what is the neutral point)? What colors are more and less saturated?

570nm...red and violet more saturated and yellow less saturated

What chromosome are S cones found on?

7

What is the prevalence of color deficiency in males? In females?

8% caucasian males, .4% females

What is the prevalence of blue cone monochromacy? What is the inheritance?

<1:100,000, x-linked

What does damage near the calcarine sulcus cause?

Cerebral achromatopsia

What is another term for saturation?

Chromatic purity

How do you quantify chromaticness?

Chromaticity=wavelength+ colorimetric purity (Because chromaticness= hue+saturation)

Hue+saturation

Chromaticness

What is the Munsell Color System used for? What are the three different assessments?

Classifying colors- hue, chroma scale, value

Color mixing by addition of energy at certain wavelengths

Color addition

If you shine two colors on a projection screen and they add, what is this an example of?

Color addition via light superimposition

If you view a painting that is actually created using a series of dots (visible up close) but from far away just looks like a painting, what is this an example of?

Color addition via pointillism

What is the Benzold-Brukcke Effect? What 3 wavelengths do not change hue with increased luminance?

Color appearance phenomenon: Hue shift with luminance Red or green light makes things look yellowish Blue/green or violet light makes things look more blue *this is a nonlinear process in the visual system after cone absorption (neurological response) 478, 503, 578-unique hues and invariant wavelength

Color mixing by the sutraction of energy at specific wavelengths

Color subtraction

What is the Hunt effect?

Colorfulness increases with luminance

How is saturation quantified?

Colorimetric purity- Munsell system, CIE chromaticity diagram

What PRs are used in bright light conditions?

Cones

What is the Stevens effect?

Contrast increases with luminance

T or F: Without cerebral functioning, we can have color vision?

FALSE

T or F: retinal BP cells are opponent cells?

FALSE

True or false: There are only rods in the periphery, no cones

FALSE, there are cones in the periphery just a less amount

T or F: dichromats only have trouble seeing saturated colors, but see unsaturated colors just fine.

FALSE- difficulty seeing saturated and unsaturated colors

True or False, you can make a CIE diagram for color addition but not color subtraction?

FALSE; you can make a CIE diagram for both addition and subtraction

T or F: All stimuli with colorimetric purity=1 will look equally saturated.

False

T or F: Hue can be used to accurately determine color deficiency or how a person perceives color

False

T or F: anomalous trichromats always behave like someone who is a deuteranope, tritanope, or protanope, depending on what wavelength they are deficient in.

False, they can behave like someone who is not color deficient

What is the anterior inferior temporal cortex involved with?

Final color processing area; color and decisions

What part of the temporal cortex is related to color processing?

Globs in the posterior inferior temporal cortex

Yellow filter+white light...what is transmitted, what is absorbed?

Green and red transmitted, blue absorbed

What is the color and pigment associated with medium-wavelength sensitive cones?

Green, chlorolabe

What's an anomalous trichromat?

Has all three types of cones but one type may not function as well or may not be present in typical numbers

What is wavelength discrimination?

How much you have to change a wavelength to notice a change in color

Which psychological property of light is a synonym to color and allows them to be classed?

Hue

What is the Abney effect? What happens to the lines on the CIE graph?

Hue change with colorimetric purity (saturation) Add white and hue changes When saturation decreased, lines on the graph are curved

What are the four psychological properties of light?

Hue, saturation, brightness, chromaticness

When retinal BP cells are inhibited they are _________ (hyperpolarized/depolarized).

Hyperpolarizeed

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I LOVE YOU

What system and law were put in place to quantify Grassman's Laws of Metamers?

Linear System, Additive Law of R+B+G=1

How is brightness quantified?

Luminance- flicker photometry, abney's law, Munsell color system

H1 horizontal cells receive input from which kind of cones?

M and L

Midget BP cells get responses from which types of cones?

M and L

Midget ganglion cells carry responses from which types of cones?

M and L

Which two types of cones are genetically similar? What chromosome are they found on?

M and L, X chromosome

Color is determined by the _________ and _________ of stimulation of the L, M, and S cones.

Magnitude and ratio

Parasol ganglion cells are involved in the ________(magnocellular/parvocellular) pathway.

Magnocellular

Colors tht appear to look alike, but do not have same spectral reflectance curve

Metamers

What does midget ganglion cells synapse with? What is the ratio of this relationship?

Midget BP cells, can be 1:1 (great detail)

What are the three types of retinal BP cells?

Midget, diffuse, cone

What are the three types of retinal ganglion cells?

Midget, parasol, small bistratified (Konio)

What is the term for a person who only has one type of cone? What do they see?

Monochromat, one color

On a CIE diagram, what do the outermost numbers represent?

Monochromatic light

In regard to saturation (colorimetric purity), in the continuum of 0-1, where are monochromatic lights found? What about pastels? What about the reference white?

Monochromatic lights- close to 1 Pastels- close to 0 Reference white- 0

Are VI blob cells monocular or binocular? Do they provide large or small details? Are they color sensitive?

Monocular, color sensitive, small details

What does color constancy mean?

Most colors remain constant despite changes in illumination, etc. Example: a yellow shirt will look yellow indoors and outdoors.

Can monochromats make wavelength based discriminations? Can dichromats?

No, yes

On a CIE diagram, what is the line at the bottom that contains no numbers? Why are there no numbers associated?

Non-spectral purples have no numbers associated because they do not have specific wavelengths because they are made through color mixes

Are parasol retinal ganglion cells involved in color?

Not really

What is the photopic luminance function like for a deuteranomalous patient?

Not significantly different from color normal

Where do horizontal cell hyperpolarize?

OPL

What are the three contributors to acquired color vision deficiency?

Ocular-thinning of NFL (glaucoma) Neurological- MS, stroke Toxicity- environmental, drugs

Small bistratified ganglion cells (konio) carry _______(on/off) center _________(S/M/L) cone responses.

On center S cone responses

Red filter+white light...what is transmitted?

Only red

What theory states that there are different channels that play against each other and together make sensation?

Opponent theory

What is the [long] pathway of the retinal ganglion cells?

Optic disc-chiasm (decussation)-optic tract-LGN (4 nuclei)

What are the two types of retinal cells that contribute to the physiology of color vision?

Retinal bipolar cells and retinal ganglion cells

What PRs are used in dark conditions?

Rods

What PRs are used in twilight conditions?

Rods and cones

What cones are the minority, S, M, or L?

S

H2 horizontal cells receive input from which kind of cones?

S but M and L too

When referring to the Munsell Color System, what does chroma scale refer to?

Saturation/colorimetric purity- pizza slice

What law states that if both sides of a metameric match are changed by an intensity of the same proportional amount, they will still match?

Scalar Grassman's Law of Metamers

What cones is a tritanope missing? What color can't they see?

Short wavelength, blue

Do shorter or longer wavelength scatter more? What is this called?

Shorter, Rayleigh scattering

What does Abney's Law of Additivity state?

The total luminance composed of a mixture of wavelengths is equal to the sum of the luminance of its monochromatic components.

Where is the Koniocellular pathway found in the LGN?

Thin layers interposed between 6 other layers

Red+Green+Blue=?

White

When the B-Y opponent color channel is stimulated equally (ML=S), what color will be perceived?

White

On a CIE diagram, what is in the center? The further a color is from the center, what happens to it?

White center. The further a color is from the white center, the more saturated it is.

What do you do when you have a super sexy boyfriend that you want to make love to?

Write a cheesy note in quizlet to remind him that you're thinking of him. I love you handsome. :)

What is the inheritance of deuteranopia? What is the prevalence in men? Women?

X linked recessive, 1% men and 0.01% women

What is the inheritance of protanopia? What is the percentage of men that have it? Women?

X linked recessive, 1% men and 0.01% women

Is saturation significantly different for a deuteranope compared to a color normal individual?

YES, significantly, 498 appears white

When the B-Y opponent color channel is stimulated with long and medium wavelengths, what color will be perceived?

Yellow

What are the exceptions to the Abney effect?

Yellow and non-spectral bluish-purples

Do rod monochromats and blue cone monochromats have decreased VAs?

Yes

Is saturation wavelength dependent?

Yes

If there is only 1 type of cone present, is it difficult to discriminate on the basis of wavelength?

Yes (could discriminate based on intensity and percent absorbance)

Do we have color vision in the periphery? Do we in mesotopic light levels?

Yes and yes

Is saturation different for protanopes?

Yes, significantly- 492nm appear white (less saturated than normal)

Is color perception stable with age?

Yes- should perceive colors differently with age but we don't because we are used to our environment so brain takes over