color vision

Where in the eye does transduction take place?

 In the retina. Transduction: taking in the energy and taking into action potential. 

All of the axons in the ganglion cell (nerve) -->

Come together in the back of the eye and form the optic nerve which turns around and exits the eye.

true or false blind in one eye optic nerve exits the retina?

true

What happens when the information gets to the visual context?

Feature detector- responsible for fire action potential when certain features are present. 

When all these patterns are put together, they are the building blocks of visual recognition.  

The blind spots are on each eye because the image is being projected at the optic nerve

give example:

example: car disappear are the blind spot

Movement detector?

Neurons exist out of the cortex → sensitive.

- movement aftereffect

- waterfall illusion

• one it stop —> experience movement in another direction.

Opponent process pairs

two neurons working together to detect.

How can we demonstrate that movement detectors exist in the brain and not in the retina?

The movement detectors are in the brain and not in the eye.

• One eye closed and one eye open to the waterfall effect, when switching eyes; the close eye still experiences.

Intraocular transfer:

Look at movement in one eye and experience the illusion in the other eye.  

Wavelength

1 nanometer (mn) = 1 billionth of a meter.

The psychological reality of color: Are the leaves truly green?

Color is not part of the object itself, it reflects the wavelength of color.

happen in visual system.

Purity

subtractive color mixing: mixing occurs outside the retina.

example: paint (blue + yellow = green)

Additive color mixing (inside of the retina)

ex: Mixing in your photoreceptors.

Physiological Basis

a. Trichromatic theory

b. Opponent process theory

c. Retinex Theory

Trichromatic theory —> in the cone

explain COLOR VISON AT THE level of retina cell

Red cone: long wavelength/see red

Green cone: intermediate (medium) wavelength/see green

Blue cone: short wavelength and see it as blue

Opponent process theory

Explain color vision at the level of ganglion cell (take place)

red/green ganglion cell- red excited action potential/green inhibited dec a.p

yellow /blue ganglion cell- yellow excite a.p/blue inhibited a.p

Retinex Theory

Explains color vision at the level of the cerebral cortex.

• The simplest term is that the cortex makes a judgment call not just judging by color wavelengths