Ch 6 Carlson

Front 1

Sensory transduction

Back 1

the process by which sensory information is “transferred” into changes in the cells’ membrane potential

Front 2

Color is perceived by 3 dimensions

Back 2

Hue
Brightness
Saturation

Front 3

3 Types of Eye Movements

Back 3

Vergence:
Saccadic:
Pursuit

Front 4

Vergence

Back 4

cooperative movements that keep both eyes fixed on the same target

Front 5

Saccadic:

Back 5

rapid, jerky movement of the eyes
--used in scanning

Front 6

Pursuit

Back 6

movement made to maintain an image of a moving object on the fovea

Front 7

Cornea

Back 7

outer layer, transparent, admits light

Front 8

Sclera

Back 8

paque, does not permit entry of light

Front 9

Iris

Back 9

pigmented ring of muscles behind the cornea

Front 10

pupil

Back 10

opening in the iris, regulates the amount of light that enters (changes size)

Front 11

Lens

Back 11

immediately behind iris, series of transparent layers
--Ciliary muscles: contraction alters shape of lens
--Accomodation – changes in lens shape permit the eye to focus images of near or distant objects on the retina

Front 12

Vitreous Humor

Back 12

clear, gelatinous substance that fills the main part of the eye. Gives the eye it’s shape.

Front 13

Iris contraction contributions to...

Back 13

Dialation; opens to allow for maximum light

Front 14

retina

Back 14

neural tissue and photoreceptive cells that line the back of the eye. Part where the light ray hits. When it hits the retina, vision is initiated.

Front 15

Visual acuity

Back 15

the ability to see detail in objects

Front 16

Photoreceptors

Back 16

rods and cons

Front 17

Fovea

Back 17

central region of the retina

Front 18

Optic Disk

Back 18

where axons conveying visual info gather together and leave the eye through the optic nerve

Front 19

Blind Spot

Back 19

produced by the optic disk because no receptors are located there

Front 20

the shape of the lens based on distance .....

Back 20

far away: the lens gets flat
Close: ciliary muscle contracts, lens gets curved

Front 21

Visual accommodation

Back 21

the process of adjusting the lens; gives us visual acuity

Front 22

cones

Back 22

1. Approximately 6 million; provide the most information about the environment. Day time vision
2. Prevalent in central retina; found in the fovea. Responsible for color vision
3. Sensitive to moderate-to-high levels of light
4. Information about hue (discriminates between different wavelengths)
5. Excellent acuity. Do not detect motion . Pretty sensitive to light.

Front 23

rods

Back 23

1. Approximately 120 million; used in dimly lit environment (more sensitive to light)
2. Prevalent in peripheral retina; not found in the fovea
3. Sensitive to low levels of light
4. Only monochromatic information
5. Poor acuity . Do detect motion

Front 24

light passage through the eye..

Back 24

1. Cornea
2. pupil
3. lens
4. vitreous humor
5. retina ... vision is iniated

Front 25

vision definition

Back 25

lihtwave into a neural message

Front 26

Rods and the cones are called_______ and are located in the _________

Back 26

photoreceptors; retna

Front 27

Cones located in the _______ of the retna

Back 27

in the phobia (center of the Retna). there are no rods here

Front 28

Rods see_________ and Cones see ______

Back 28

Rods: black white and grey
Cones: color; hues

Front 29

Anatomy of the Retina

Back 29

Photoreceptor layer
Bipolar Cell Layer
Ganglion Cell Layer:
Horizontal cells
Amacrine cells

Front 30

optic disk

Back 30

where the axons come together to form the optic nerve; there are no rods or cones here. Blind spot

Front 31

Photoreceptor layer

Back 31

back of retina; rods and cones; forms connections with bipolar cells. Deepest layer of the retina

Front 32

Bipolar cell layer

Back 32

connects the photoreceptor and ganglion cell layers; forms synapses with ganglion cells. The axon’s meet and form the optic nerve.

Front 33

Ganglion Cell Layer

Back 33

axons travel through optic nerves and carry visual information to the brain.

Front 34

Horizontal cells:

Back 34

interconnect adjacent photoreceptors and outer processes of bipolar cells

Front 35

Amacrine cells

Back 35

interconnect adjacent ganglion cells and inner processes of bipolar cells

Front 36

Photopigments

Back 36

a protein dye bonded to retinal, a substance derived from Vitamin A
-- Responsible for transduction of visual information
-- 3 in cones; 1 in rods

Front 37

2 parts of photopigments

Back 37

opsin + retinal

Front 38

Rhodopsin

Back 38

particular opsin found in rods. When light hits rhodopsin, the light breaks it into opsin and retinal.

Front 39

NT released by vision

Back 39

glutamate

Front 40

Glutamate in vision system is ___________

Back 40

inhibitory

Front 41

In vision hyperpolarization reduces the __________

Back 41

release of glutamate

Front 42

Light does _______ to the photopigments

Back 42

Bleaches it. Takes it from pink to a very pale yellow;

Front 43

Retino-geniculate-cortical pathway

Back 43

visual neural pathway
eye to the cortex

Front 44

Axons of the retinal ganglion cells

Back 44

bring information to the brain, ascend through optic nerves, to the dorsal lateral geniculate nucleus in the thalamus

Front 45

6 Layers of the Dorsal LGN

Back 45

--Magnocellular layers = inner 2 layers, large cell bodies
Transmits information necessary for perception of form, movement, depth, and small differences in brightness. It’s colorblind. Does not detect fine detail.
---Parvocellular layers = outer 4 layers, small cell size
Transmits information necessary for perception of color and fine details. Color vision. Newer part of the geniculate nucleus. Detects fine detail. High spatial resolution

Front 46

association cortexs

Back 46

processes the meaning

Front 47

Receptive field

Back 47

the portion of the visual field in which presentation of visual stimuli will produce an alteration in the firing rate of a particular neuron

Front 48

Two streams of visual analysis

Back 48

Dorsal stream
Ventral stream

Front 49

Dorsal Stream

Back 49

recognizes where the object is located and whether it is moving
Terminates in posterior parietal lobe
----Receives mostly magnocellular input

Front 50

Ventral Stream

Back 50

recognizes what an object is and what color it has
Terminates at inferior temporal cortex
Receives approximately equal input from magnocellular and parvocellular/koniocellular systems

Front 51

Subarea V4

Back 51

(extrastriate cortex) = analysis of form and color
Damage to V4 = color constancy disruption

Front 52

TEO

Back 52

(inferior temporal cortex) = color vision
Damage to TEO = severe color vision impairment/color perception

Front 53

V8

Back 53

(inferior temporal cortex) = color perception AND memories of colors of particular objects
Damage to V8 = cerebral achromatopsia (inability to discriminate among different hues; “vision without color”)

Front 54

striate cortex

Back 54

contains neurons that are sensitive to to orientation and spatial frequency
---send information to the extrastriate cortex

Front 55

extrastriate cortex subregions

Back 55

These subregions analyze the info and send it along the ventral stream toward the temporal neocortex

Front 56

Inferior temporal cortex (ventral stream)

Back 56

Recognition of visual patterns and identification of particular objects
Analyses of form and color are put together and perceptions of 3D objects and backgrounds are achieved

Front 57

2 major regions of inferior temporal cortex

Back 57

posterior area (TE) and anterior area (TEO)

TE and TEO participate in the recognition of objects – rather than the analysis of specific features

Damage = severe deficits in visual discrimination

Front 58

Visual Agnosia

Back 58

deficits in visual perception in the absence of blindness

Front 59

Apperceptive visual agnosia

Back 59

failure to perceive objects; still able to read and recognize objects by touch

*****Damage to ventral stream

Front 60

Associative visual agnosia

Back 60

inability to identify objects that are perceived visually; form of the perceived object can be drawn or matched with similar objects

Difficulty transferring visual information to verbal mechanisms

****Cause = disruption of connections between the ventral stream and the brain’s verbal mechanisms

Front 61

Prosopagnosia

Back 61

failure to recognize particular people by the sight of their faces; can recognize that they are looking at a face, but cannot say whose face it is
usually recognize people by their voice
***damage to Fusiform face area (FFA):

Front 62

Fusiform face area (FFA):

Back 62

involved in perception of faces and other complex objects that require expertise to recognize

Front 63

V5 (medial temporal, MT):

Back 63

movement

***Damage to V5 = severely disrupts ability to perceive moving stimuli

Front 64

MST (medial superior temporal)

Back 64

complex patterns of movement (radial, circular, and spiral motion)

Front 65

MSTd (dorsolateral MST)

Back 65

analysis of optic flow
Information about the relative distance of objects from the observer and of the relative direction of movement

Front 66

Perception of Motion (V5)

Back 66

Bilateral damage to area of brain that includes V5 = akinetopsia (inability to perceive movement)

Front 67

Optic Flow (MT+)

Back 67

Lesion = perceive motion but cannot perceive heading from optic flow

Front 68

Form from Motion

Back 68

perception of movement can help us perceive 3D forms
Lesion = no perception of form from motion

Front 69

Biological Motion

Back 69

(Extrastriate Body Area) neurons activated by sight of human body parts

Front 70

Balint’s Syndrome:

Back 70

bilateral damage to the dorsal stream. In your parietal occipital region ; 3 major symptoms.

1) Optic ataxia: deficit in reaching for objects under visual guidance

2) Ocular apraxia: deficit of visual scanning. They cannot scan a room and get all the objects in it.
3) Simultanagnosia: difficulty in perceiving more than one object at a time.

Front 71

Extrastriate cortex

Back 71

region of the visual association cortex that surrounds the striate cortex
--Receives fibers from striate cortex and superior colliculi
--Projects to the inferior temporal cortex