Explain how color vision works; that is, how are we able to perceive color, what neural processing happens tha

Question

Explain how color vision works; that is, how are we able to perceive color, what neural processing happens that enables us to experience the sensation of color?

Answer 1

The colour sensors consist of light sensitive receptors (cones). There are three types, each sensitive to different wavelengths. When enough photons (I think it may be a minimum12) hit a receptor, it activates a signal back along the nerve to the brain, which tells it that a receptor of that wavelength has been activated, and its intensity. All the visible colours are just mixtures of various intensities of the three different wavelengths.

Hope this helps.

Answer 2

Color vision is the capacity of an organism or machine to distinguish objects based on the wavelengths (or frequencies) of the light they reflect or emit. The nervous system derives color by comparing the responses to light from the several types of cone photoreceptors in the eye. These cone photoreceptors are sensitive to different portions of the visible spectrum. For humans, the visible spectrum ranges approximately from 380 to 750 nm, and there are normally three types of cones. The visible range and number of cone types differ between species.

A 'red' apple does not emit red light. Rather, it simply absorbs all the frequencies of visible light shining on it except for a group of frequencies that is perceived as red, which are reflected. An apple is perceived to be red only because the human eye can distinguish between different wavelengths. Three things are needed to see color: a light source, a detector (e.g. the eye) and a sample to view.

Color perception
Perception of color is achieved in mammals through color receptors containing pigments with different spectral sensitivities. In most primates closely related to humans there are three types of color receptors (known as cone cells). This confers trichromatic color vision, so these primates, like humans, are known as trichromats. Many other primates and other mammals are dichromats, and many mammals have little or no color vision.

In the human eye, the cones are maximally receptive to short, medium, and long wavelengths of light and are therefore usually called S-, M-, and L-cones. L-cones are often referred to as the red receptor, but while the perception of red depends on this receptor, microspectrophotometry has shown that its peak sensitivity is in the yellow region of the spectrum.

Cone cells in the human eye
Cone type/ Name Range / Peak sensitivity
S β (Blue) / 400..500 nm / 420 nm
M γ (Bluish-Green) / 450..630 nm / 534 nm
L ρ (Yellowish-Green) / 500..700 nm / 564 nm

The pigments present in the L- and M-cones are encoded on the X chromosome; defective encoding of these leads to the two most common forms of color blindness.

Answer 3

eyes cones/rods brain magic!