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
You're a rockstar my love! I miss you and can't wait to cuddle all weekend.
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