Vision

Question 1

specialized to absorb one kind of energy and transduce it into an electrochemical pattern in the brain.

Answer 1

receptor

Question 2

how fast a neuron is firing

Answer 2

frequency of a response

Question 3

defined as waves of electromagnetic energy between 400 and 700 nanometers (billionths of a meter) in length.

Answer 3

LIGHT

Question 4

Indicates perception of color

Answer 4

WAVELENGTH

Question 5

PIndicates perception of brightness

Answer 5

INTENSITY

Question 6

Regulates the amount of light passing through.
Controls the size of the pupil.
Donut-shaped bands of contractile tissue.
Gives our eyes their color.

Answer 6

Iris

Question 7

The hole in the iris where light enters.
Adjusts in response to changes in illumination.

Answer 7

Pupil

Question 8

The ability to detect the presence of dimly lit objects.

Answer 8

Sensitivity

Question 9

Ability to see the details of an object.

Answer 9

Acuity

Question 10

Focuses incoming light on the retina.
Transparent, behind the pupil.

Answer 10

Lens

Question 11

Increases the ability of the lens to refract (bend) light and thus brings close objects into sharp focus.

Answer 11

Ciliary muscles

Question 12

The process of adjusting the configuration of the lenses to bring images into focus on the retina.

Answer 12

Accommodation

Question 13

Clear, dome-shaped covering of the eyes.
Surface of the eyes.
Responsible for refraction of light.

Answer 13

Cornea

Question 14

Tough white outer layer of the eyeball.

Answer 14

Sclera

Question 15

Contains photoreceptors; lines the interior of the eye.
Converts light to neural signals and conducts them to the CNS for processing.

Answer 15

Retina

Question 16

Detects and converts light to neurosignals.

Answer 16

Photoreceptors

Question 17

Two kinds of photoreceptors

Answer 17

Rods and cones

Question 18

Responsible for vision in low light (120 million in an eye).
Light sensitive.
At the periphery of the retina.
High sensitivity, low acuity

Answer 18

Rods

Question 19

Responsible for color vision (6 million in an eye).
Color sensitive.
Densely packed at Fovea.
Low sensitivity, high acuity

Answer 19

Cones

Question 20

the image falling on each retina is sharper and there is a greater depth of focus.

Answer 20

CONSTRICTION

Question 21

let in more light, thereby sacrificing acuity and depth of focus.

Answer 21

DILATION

Question 22

the difference in the position of the same image on the two retinas—is greater for close objects than for distant objects.

Answer 22

BINOCULAR DISPARITY

Question 23

The theory that cones and rods mediate different kinds of vision.

Answer 23

Duplexity Theory

Question 24

Cone-mediated vision.
Predominates in good lighting and provides high acuity (finely detailed)

Answer 24

Photopic vision

Question 25

Rod-mediated vision. Lacks both the detail and the color of photopic vision.

Answer 25

Scotopic vision

Question 26

Indentation at the center of the retina. Central vision, specialized for high acuity vision. Packed with cones.

Answer 26

Fovea

Question 27

Types of neurons in the eyes

Answer 27

Photoreceptors Horizontal cells Bipolar cells Amacrine cells Ganglion cells

Question 28

Integrates signals from across the surface of the retina.

Answer 28

Horizontal cells

Question 29

Forms part of the straight pathway bet. the photoreceptors and the ganglion cells.

Answer 29

Bipolar cells

Question 30

Integrates signals across adjacent segments of the retina.

Answer 30

Amacrine cells

Question 31

Containing axons and dendrites that connect the ganglion, bipolar, and amacrine cells.

Answer 31

Ganglion cells

Question 32

Types of ganglion cells

Answer 32

Parvocellular neurons Magnocellular neurons Koniocellular neurons

Question 33

Small cell bodies and receptive fields Mostly in or near the fovea Detect visual details Respond to color Still objects Outer four layers.

Answer 33

Parvocellular neurons

Question 34

Larger cell bodies and receptive fields Distributed evenly throughout the retina Not color sensitive Respond strongly to moving stimuli Respond to large overall patterns but not to details Inner two layers.

Answer 34

Magnocellular neurons

Question 35

A ganglion cell with several functions. Axons terminate in several locations. Ventral layer.

Answer 35

Koniocellular neurons

Question 36

carries the image formed on the retina to the brain in the form of electrical signal.

Answer 36

Optic nerve

Question 37

The point at which the optic nerve leaves the eye and also where blood vessels enter and leave. Has no receptors, therefore, no vision is perceived at this spot.

Answer 37

Blindspot

Question 38

The "what" pathway. Specialized for identifying and recognizing objects. Temporal lobe is involved.

Answer 38

Ventral stream

Question 39

The "where" or "how" pathway Helps the motor system find and use objects. Parietal lobe is involved.

Answer 39

Dorsal stream

Question 40

Lobe for ventral stream

Answer 40

Temporal lobe

Question 41

Lobe for dorsal stream

Answer 41

Parietal lobe

Question 42

Visual pathway

Answer 42

Cornea > iris > pupil > lens > retina (receptors & bipolar cells > sends message to: ganglion cells > axons form: optic nerve) > optic chiasm > lateral geniculate nucleus > primary visual cortex > secondary visual cortex > temporal and parietal lobes

Question 43

the conversion of light to neural signals by the visual receptors.

Answer 43

VISUAL TRANSDUCTION

Question 44

photopigment found in rods.

Answer 44

RHODOPSIN

Question 45

Rods in the dark...

Answer 45

1. Rhodopsin molecules are inactive. 2. Sodium channels are kept open. 3. Sodium ions flow into the rods, partially depolarizing them. 4. Glutamate is released, depolarizing the membrane. 5. Glutamate acts as an inhibitor, making bipolar cells hyperpolarized = at rest = no action potential. 6. No signal at ganglion cells = no color vision.

Question 46

Rods in light...

Answer 46

1. Light bleaches rhodopsin molecules. 2. Sodium channels close. 3. Sodium ions cannot enter rods, and the rods become hyperpolarized. 4. Glutamate release is reduced. 5. No more inhibition of transmission to bipolar cells. 6. Bipolar cells can now release neurotransmitters to ganglion cells.

Question 47

According to this theory, there are three different kinds of color receptors (cones), each with a different spectral sensitivity, and the color of a particular stimulus is presumed to be encoded by the ratio of activity in the three kinds of receptors.

Answer 47

TRICHROMATIC THEORY

Question 48

Proponents of trichromatic theory

Answer 48

Thomas Young and Hermann von Helmholtz

Question 49

• suggested that there are two different classes of cells in the visual system for encoding color and another class for encoding brightness. • perceive color in terms of opposites because the brain has a mechanism that perceives color on a continuum from red to green, another from yellow to blue, and another from white to black.

Answer 49

OPPONENT-PROCESS THEORY

Question 50

Proposed the OPPONENT-PROCESS THEORY

Answer 50

Ewald Hering

Question 51

are pairs of colors (e.g., green light and red light) that produce white or gray when combined in equal measure.

Answer 51

COMPLEMENTARY COLORS

Question 52

• refers to the fact that the perceived color of an object is not a simple function of the wavelengths reflected by it. • ability to recognize colors despite changes in lighting.

Answer 52

COLOR CONSTANCY

Question 53

a visual agnosia for faces that can be acquired either during development (developmental prosopagnosia) or as a result of brain injury.

Answer 53

PROSOPAGNOSIA

Question 54

difficulties recognizing movement.

Answer 54

MOVEMENT AGNOSIA

Question 55

difficulties recognizing objects.

Answer 55

OBJECT AGNOSIA

Question 56

difficulties recognizing colors.

Answer 56

COLOR AGNOSIA

Question 57

• is a deficiency in the ability to see movement progress in a normal smooth fashion. • can be triggered by high doses of certain antidepressants.

Answer 57

AKINETOPSIA