Color vision
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Color vision. Outlines. What is color Retinal circuitry for color vision Several ways to label retinal cells. Color history: discovery of color. Isaac Newton. Color history: discovery of color. Reflection makes colors. Retina anatomy of human being. Outer nuclear layer.

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Color vision

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Color vision

Color vision


Color vision

Outlines

  • What is color

  • Retinal circuitry for color vision

  • Several ways to label retinal cells


Color vision

Color history: discovery of color

Isaac Newton


Color vision

Color history: discovery of color


Color vision

Reflection makes colors


Retina anatomy of human being

Retina anatomy of human being

Outer nuclear layer

Outer plexiform layer

Inner nuclear layer

Inner plexiform layer

Ganglion cell layer


Cone mosaic in human retina

Cone mosaic in human retina

Immunohist-ochemistry (IHC)

S-cone

L-cone

S-cone

M-cone

L-cone or M-cone


Color vision

Immunohist-ochemistry (IHC)


Trichromats vs dichromats

TrichromatsvsDichromats


Color vision

  • Strategy to see color

  • Principle of Univariance: any single photopigment is “colour blind”. Given proper combination of wavelength and intensity, and can trigger same response in M-cone.

  • Color-coding ganglion cells receive antagonistic input from cones: red-green; yellow-blue


Color vision

Color opponency mechanism

Red-greenopponent cells:

midget ganglion cells

Blue-yellowopponent cells:

small bistratified ganglion cells

1111

Review by Dacey, 2000


Color vision

Dichromats

Review of Masland, 2012


Color vision

S/M opponent ganglion cells in retina of guinea pig

a dichromatic mammal

Dye iontophoresis


Color vision

Dye iontophoresis

What is

?

To dye fill a cell:

visualize the cell via quick and rough nucleus staining

A microelectrode filled with fluorescent dye is placed carefully in contact with the soma

Break into the cell and apply current. “injecting fluorescent dye into the cell electronically”.

How big is 10μm? The width (diameter) of a human hair ranges from 0.017 to 0.181 mm.


Color vision

Movie showing iontophoresis of dye into retinal ganglion cell


Summary of cell labeling techniques

Summary of cell labeling techniques

Immunocytochemistry

Dye-filling

3. Genetic tags: GFP, YFP…


History of genetic tag gfp

History of genetic tag: GFP

2008 Nobel prize winners Osamu Shimomura, Martin Chalfie, and Roger Tsien,


Transgenic lines that mark rgc subtypes

Transgenic lines that mark RGC subtypes

Genetic tags: YFP


Color vision

The End

“Most of my knowledge came from self-study,” says Dr. Shimomura. “If you find an interesting subject, study it through to the finish. If you confront difficulties, overcome them. Don’t be discouraged. There are always difficulties in research.”


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