Vision Flashcards
Unit 3
The most sensitive to wavelengths of energy called visible spectrum:
Human Photoreceptors
The distance from the peak of one wave to the peak of the next wave and corresponds to the perceptual term ‘hue’ or color.
Wavelengths
Short Wavelength:
Bluish color
Medium Wavelength:
Greenish color
Long Wavelength:
Reddish color
Corresponds to perceptual term brightness and is measured by the height of the wave:
Amplitude/Intensity
Large amp./intensity:
Bright color
Small amp./intensity:
Dull color
A specialised, transparent portion of the sclera through which light enters, allowing us to focus light more sharply:
Cornea
What protects the eye?
Cornea
Pigmented muscle that gives the eye its color and regulates the amount of light:
Iris
Dark hole in the center of the iris that reduces glare; the size of the opening depends on the amount:
Pupil
Reacts to bend the rays of light so that the light is properly focused on the rear of the eye; this focuses light by changing its own:
Lens
Layers of cells containing photoreceptors, rodes, and cones that transduce light energy to electrochemical energy:
Retina
Operates like film in a camera:
Retina
Area in the center of the retina where vision is shaped:
Fovea
The point of central focus:
Fovea
Bundle of ganglion axons that lead out of the eye toward the brain carring info about light:
Optic Nerve to Visual Cortex
Location on the retina where the optic nerve leaves the eye on its way to the brain:
Blind Spot
The process by which the eye’s lens changes shape to help focus near or far objects on the retina:
Accommodation
Too much curvature of the lens:
Nearsighted Vision
Too little curvature of the lens:
Farsighted Vision
The light rays from distant objects focus in the middle of the retina, so when their image reaches the fovea, the rays are spreading out, blurring the image:
Nearsighted Vision
The light rays from nearby objects come into focus behind the fovea, resulting in blurred images:
Farsighted Vision
Irregularity in the shape of the cornea or lens causing distorted/blurred images on the fovea:
Astigmatism
Located in the retina’s periphery:
Rods
These receive light energy in low light but are unable to detect colors and function in night vision:
Rods
Located in the middle of the retina:
Cones
Detect color in brighter light and function in the daytime:
Cones
Both rods and cones synapse with ___ cells which come together to form ____ cells:
Bipolar; Ganglion
Ganglion cells come together to form your ____:
Optic Nerve
Junction of the two optic nerves where fibers from nasal sides of the two retinas cross:
Optic Chiasm
Point at which approx. 2/3 of the fibers that make up the optic nerve cross over the midline of the brain:
Optic Chiasm
Located in the occipital lobe of both hemispheres which contain he many specialized cells for visual perception:
Visual Cortex
Activation of neurons in the cortex that respond to specific features of the stimulus (shape, angle, movement, etc):
Feature Detectors
Processing of several aspects of the stimulus simultaneously. The brain divides a visual scene into subdivisions such as color, depth, form, movement, etc:
Parallel Processing
Who won a Nobel prize for the Parallel Processing research?
David Hubel and Torsten Wiesel
A. Three different types of photoreceptors are sensitive to different ranges of wavelengths; ___, ____, and ____ cones:
Red, blue, green
B. Each color you see results from a specific ____ of activation among the three types of receptors:
Ratio
What color results from stimulation of red and green cones?
Yellow
C. The Trichromatic Theory is used to explain ______:
Colorblindness
The most common colorblindess is caused by a malfunction in the ___ cone system:
Green
Which theory are questions A, B, and C relating to?
Young-Helmholtz Trichromatic Theory
Created the Opponent Process Theory:
Edward Hering
Suggests that receptor cells are linked in pairs, working in opposition to each other:
Opponent Process Theory
In the _____, some neurons are turned on by red but off by green:
Thalamus
List each colors’ opposite:
Red and ____
Blue and ____
White and ____
Green, Yellow, Black
Color of an object remains the same under different illuminations. However, when the context changes, the color of an object may look different:
Color Constancy
