AP Psych Chapter 5: Vision
Farsightedness
A condition in which far away objects are seen more clearly than nearly objects because nearby objects focus in front of the retina
Nearsightedness
A condition in which nearby objects are seen more clearly than distant objects because distant objects focus in front of the retina
Lateral Geniculate Nucleus
A relay center in the thalamus for the visual pathway. Receives major sensory input from the retina. The main connection of the optic nerve to the occipital lobe. From here light travels to the visual cortex. Inside the thalamus. From here it travels to the visual cortex.
Bipolar cells
Act to transmit signals from photoreceptors to the ganglion cells.
Optic nerve
Carries information to the brain
Blind spot
Created where the optic nerve leaves the eye and there are no receptor cells
Optic Chiasm
Formed at the point below the brain where the two optic nerves cross over each other. Before light passes through the LGN.
Monochromats
Have either no functioning cones or only one functioning cone type and respond to light the same way a black and white movie does. Sees different shades of grey.
Pupil
Light passes through here after the cornea. It is a small adjustable opening
MAI
Movement after image. Caused by adaptation of motion. Specific detectors that are tuned to the direction of movement of the stimuli being viewed.
Feature detectors
Neurons that receive information and respond to a scene's specific figures. To edges, lines, angles, and movements.
Dichromats
One malfunctioning cone system. Either lack the ability to see the difference between green and red or less commonly between blue and yellow.
Sensory adaptation
Our diminishing sensitivity to an unchanging stimulus
Color Constancy
Perceiving familiar objects as having consistent color, even if changing illumination alters the lighting
The electromagnetic spectrum
Ranges from imperceptibly short waves of gamma rays, to the narrow band that we see as visible light, to the long waves of radio transmission
Cones
Sensory neurons that are less sensitive to light than rods. They require bright light. They are specialized to see color, they are detail sensitive, and they are located on the fovea of the retina. Photoreceptors.
Rods
Sensory neurons that are very sensitive to light and are needed to see in dim conditions. Photoreceptors. They fire less frequently over time resulting in sensory adaptation. They are numerous and detect black, white, and grey. Located around the periphery of the retina
Intensity
The amount of energy in light waves determined by a wave's amplitude or height
Hue
The color we experience from a light wave
Light's wavelength
The distance from one wave peak to the next determines its hue
Retina
The eyeball's light-sensitive surface on which the rays focus. Multilayered tissue.
Cornea
The part of the eye where light initially enters. It protects the eye and bends light to provide focus.
Sensory transduction
The process by which our sensory systems convert stimulus energy into neural messages
Parallel Processing
The processing of several aspects of a problem simultaneously; the brain's natural mode of information processing for many functions, including vision.
Young-Helmholtz trichromatic theory
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.
Fovea
The retina's area of central focus. Cones are located here.
Acuity
The sharpness of vision
Lens
This is behind the pupil and it focuses the incoming rays into an image on the eye's light-sensitive back surface. It changes its curvature in a process called accommodation
Iris
This regulates the size of the pupil. It is a colored muscle surrounding the pupil. It adjusts light intake by dilating and constricting in response to light intensity and even to inner emotions.
Ganglion cells
Transmit image-forming and non image-forming visual information from the retina in the form of action potential regions of the brain such as the thalamus, hypothalamus, etc. Axons from ganglion cells converge to form the optic nerve.
Opponent processing theory
Two processes that work opposite of one another. For example: Red creates a green after image and blue creates a yellow after image.
Illusory contours
Visual illusions that evoke the perception of an edge. To fill in missing info.
Blindsight
When people experience blindness in part of their field of vision due to a lost portion of their brain's visual cortex.