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.