Vision

10. the theory that opposing retinal processes (red-green, yellow-blue, white-black) enable color vision. For example, some cells are stimulated by green and inhibited by red; others are stimulated by red and inhibited by green.
11. the light-sensitive inner surface of the eye, containing the receptor rods and cones plus layers of neurons that begin the processing of visual information.
12. the transparent structure behind the pupil that changes shape to help focus images on the retina.
14. retinal receptors that detect black, white, and gray; necessary for peripheral and twilight vision, when cones don’t respond.
15. the dimension of color that is determined by the wavelength of light; what we know as the color names blue, green, and so forth.
16. nerve cells in the brain that respond to specific features of the stimulus, such as shape, angle, or movement.
17. the distance from the peak of one light or sound wave to the peak of the next. Electromagnetic wavelengths vary from the short blips of cosmic rays to the long pulses of radio transmission.

1. the point at which the optic nerve leaves the eye, creating a “blind” spot because no receptor cells are located there.
2. the central focal point in the retina, around which the eye’s cones cluster.
3. a ring of muscle tissue that forms the colored portion of the eye around the pupil and controls the size of the pupil opening.
4. the adjustable opening in the center of the eye through which light enters.
5. the amount of energy in a light or sound wave, which we perceive as brightness or loudness, as determined by the wave’s amplitude.
6. the nerve that carries neural impulses from the eye to the brain.
7. retinal receptor cells that are concentrated near the center of the retina and that function in daylight or in well-lit conditions. The cones detect fine detail and give rise to color sensations.
8. the process by which the eye’s lens changes shape to focus near or far objects on the retina.
9. the processing of many aspects of a problem simultaneously; the brain’s natural mode of information processing for many functions, including vision. Contrasts with the step-by-step (serial) processing of most computers and of conscious problem solving.
13. the theory that the retina contains three different color receptors—one most sensitive to red, one to green, one to blue—which, when stimulated in combination, can produce the perception of any color.