Question

What specific brain region is responsible for maintaining the perception of color. Give an example for what correct color constancy would look like. Why is it much harder to perceive color in the dark than in the light?

Answer 1

Using fMRI brain imaging, scientists found three main areas stimulated by colour: V1, an area in the ventral occipital lobe, specifically the lingual gyrus, which was designated as human V4, or hV4, and another area located anteriorly in the fusiform gyrus, designated as V4α.

Visual cortex. The visual cortex of the brain is that part of the cerebral cortex which processes visual information. It is located in the occipital lobe.

Human color vision relies on three photoreceptors that detect primary colors—red, green, and blue. However, some people lack red photoreceptors (they are “bichromates”) or have an additional photoreceptor that detects somewhere between red and green colors (“tetrachromates”). Obviously, having only 3 photoreceptors doesn’t limit our ability to distinguish other colors.

Each photoreceptor can absorb a rather broad range of wavelengths of light. To distinguish a specific color, the brain compares and quantitatively analyses the data from all three photoreceptors. And our brain does this remarkably successfully—some research indicates that we can distinguish colors that correspond to wavelength differences of just 1 nanometer.

This scheme works in largely the same way in most higher vertebrate animals that have color vision. Although the ability to distinguish between specific shades varies significantly between the species, with humans having one of the best color distinguishing abilities.

However, invertebrates that have developed color vision (and vision in general) completely independently from us demonstrate remarkably different approaches to color detection and processing. These animals can have a exceptionally large number of color receptors. The mantis shrimp, for instance, has 12 different types of photoreceptors.