Vision and Visual Processing

These flashcards cover key concepts related to the chapter on vision, visual processing, and pathways in the visual system.

Retina

The receptive surface inside the eye that contains photoreceptors and other neurons.

Transduction

The conversion of one form of energy to another, such as from light to neuronal activity.

Cornea

The transparent outer layer of the eye, which is primarily responsible for forming the image on the retina.

Refraction

The bending of light rays by a change in the density of a medium.

Lens

A structure in the eye that helps focus an image on the retina.

Ciliary muscle

A muscle that controls the shape of the lens inside the eye.

Accommodation

The process by which the ciliary muscles adjust the lens to bring nearby objects into focus.

Myopia

Nearsightedness; difficulty seeing distant objects due to incorrect focus on the retina.

Photoreceptor

A neural cell in the retina that responds to light.

Rod

A type of photoreceptor cell most active at low levels of light.

Cone

Any of several classes of photoreceptor cells responsible for color vision.

Bipolar cell

An interneuron in the retina that receives information from rods and cones.

Ganglion cell

A cell in the retina whose axons form the optic nerve.

Optic nerve

The collection of ganglion cell axons that extends from the retina to the brain.

Horizontal cell

A special retinal cell that contacts both photoreceptors and bipolar cells.

Amacrine cell

A type of retinal cell that contacts both bipolar cells and ganglion cells.

Scotopic system

A visual system that operates in low levels of light and involves rods.

Photopic system

A visual system that operates in bright light and involves cones.

Rhodopsin

The photopigment in rods that responds to light.

Acuity

The sharpness of vision, which is best at the fovea.

Fovea

The central portion of the retina that has the highest density of photoreceptors.

Blind spot

The region of the retina that is devoid of photoreceptors due to the exit of the optic nerve.

Optic chiasm

The point where parts of the optic nerves cross the midline.

Lateral geniculate nucleus (LGN)

The part of the thalamus that receives visual information from the optic tract.

Extrastriate cortex

Visual cortex areas outside of the primary visual cortex (V1).

Spectral opponency

A characteristic of neurons that respond oppositely to different wavelengths of light.

Trichromatic hypothesis

The hypothesis that color perception is based on three types of cone receptors.

Opponent-process hypothesis

The theory that color perception depends on a system of opposing responses to different colors.

Dorsal stream

The visual processing stream responsible for spatial location and movement.

Ventral stream

The visual processing stream primarily responsible for recognizing objects and faces.

Blindsight

A condition in which individuals cannot consciously perceive visual cues but may still be able to make some visual discrimination.

Amblyopia

Reduced visual acuity that is not caused by optical or retinal impairments.