I would presume that is has something to do with synapses and specific chemicals starting specific charges through the optical nerve's sub-components, and that this is somehow interpreted by the brain to configure an actual image; but in all honesty I have no idea.

The eye is obviously quite complex, and as I am not massively associated with all the terminology yet, I would be grateful for an answer in layman's terms.


closed as too broad by kmm, WYSIWYG Jan 17 '17 at 13:41

Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. Avoid asking multiple distinct questions at once. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

  • 1
    $\begingroup$ This is a very broad question. Even a seemingly simple thing as color code is quite complex at the neurophysiological level. Could you by any chance narrow down the question to a particular anatomical part of the visual system and a particular process (e.g. color vision or contrast) $\endgroup$ – AliceD Jan 16 '17 at 18:27
  • $\begingroup$ Yes, I thought that might be the case. Yes of course, colour vision would be the most useful. $\endgroup$ – rj60001 Jan 16 '17 at 19:01

Color vision in layman's terms:

The eyes contain a photosensitive layer much like a digital camera called the retina. In the center of this layer is a 3 mm-wide spot called the fovea that contains high densities of photosensitive cells, called the cones. Cones are photon hungry and operate only in bright light (photopic vision). They are called cones because of their conical shape. Rods are abundant in the periphery and mediate gray-scale night vision (scotopic vision).

The cones in the fovea are present in three types: red, green and blue cones - hence they convey color images much like digital pictures, namely as a bunch of pixels with a mixture of red, green and blue.

The cones in the retina are the first nerve cells (called neurons) in a long chain of neurons. The cones are hence called primary neurons. They connect to secondary neurons, namely the retinal ganglion cells (RGCs). These cells have long protrusions called axons. These axons bundle together to form the optic nerve. Each cone in the fovea connects to one RGC. The optic nerve extends from the retina to the brain. Information is sent through the optic nerve in the form of electrical pulses, just like a photosensitive chip operates in a camera. The information from the optic nerve eventually reaches the primary visual cortex in the brain, also referred to as V1 or striate cortex (Fig. 1).

In the visual cortex, there is a retinotopic map, meaning that a topographic representation exists in the brain that matches the retinal image. In other words, images are projected faithfully on the brain's surface as neuronal activity. The brain's job is to process these images further and generate conscious perceptions out of them; we see with the brain, not the eyes (a famous quote from Bach-y-Rita).

eye pic
Fig. 1. The visual system. source: IEEE

- Kolb et al., Webvision. The Organization of the Retina and Visual System. Utah University
- Purves et al., Neuroscience 2nd ed. Sunderland (MA): Sinauer Associates; 2001

  • 1
    $\begingroup$ Thank you so much! Really in depth answer, thanks again! $\endgroup$ – rj60001 Jan 16 '17 at 21:56
  • $\begingroup$ @rj60001 - no worries and happy to help :) also, feel free to ask additional questions on the visual system. I had to narrow down the scope of this question to make it answerable. $\endgroup$ – AliceD Jan 16 '17 at 22:01
  • 1
    $\begingroup$ Yes of course, if I am studying Synthetic Biology and researching on how that could be applied to the eye (as well as how theoretically digital cameras could be hooked up) so I am bound to come up with more questions. In which case I will ask here first. :) $\endgroup$ – rj60001 Jan 16 '17 at 22:13

Not the answer you're looking for? Browse other questions tagged or ask your own question.