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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Outlines

  • What is color

  • Retinal circuitry for color vision

  • Several ways to label retinal cells





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



Trichromats vs dichromats
TrichromatsvsDichromats


  • 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 opponency mechanism

Red-greenopponent cells:

midget ganglion cells

Blue-yellowopponent cells:

small bistratified ganglion cells

1111

Review by Dacey, 2000


Dichromats

Review of Masland, 2012


S/M opponent ganglion cells in retina of guinea pig

a dichromatic mammal

Dye iontophoresis


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.


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,



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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