Visual Processing by the Retina

VISUAL PERCEPTION BEGINS in the retina and occurs in two stages. Light entering the cornea is projected onto the back of the eye, where it is converted into an electrical signal by a specialized sensory organ, the retina. These signals are then sent through the optic nerve to higher centers in the brain for further processing necessary for perception. In this chapter we describe the neural processing of visual signals in the retina. The next three chapters explain, in cell-physiological terms, how processing in higher centers underlies the perception of form, motion, and color.