How is sight processed?

Answer 1

Dear mommy2,
The image activates transmission in the retinal cell, which passes chemical information to a nerve cell in back of the eye. The nerve cell has a connection with another nerve, and it connects to another one in the visual cortex in back of the brain. The messages from the right eye go to the left brain and vice versa, no one knows why (but the anatomy shows how: the nerve tracks actually cross each other going to their destinations). All of the information passed is by chemicals (neurotransmitters). At the visual cortex, which nerves fire apparently is important in what you 'see'.

Answer 2

An image is received on the photoreceptor neurons of the retina, stimulating them to signal. From this point on there are a number of relay circuits, from neuron to neuron, as the signal passes from the retina, through the optic nerve, on to the midbrain (in the lateral geniculate nucleus) and the structures known as the colliculus, then on to the visual cortex, a specific region of the brain. Astonishingly enough, the neurons that are located in the visual cortex show selective sensitivity to the orientation of light and its relative intensity. Some neurons in visual cortex do not respond to light unless it is coming from a moving image, some only respond to light that is oriented in a specific pattern. From all of this we get the perception of visual input.

As was mentioned by one of the other answers, the visual output from a given retina is actually split as it goes to the brain. The signal seen by the half of the retina closer to your nose, actually goes through circuits that cross-over from one side of the brain to the other. The signals from the half of the retina that is closest to your temples actually transmits to the brain on the same side of the head. More fun facts, Siamese cats and some albino animals do not show this type of crossing over.

Answer 3

A PUPIL IN YOUR EYE HELPS U SEE EVERYTHING