Psyc 304 Chap 4 Visual System

Front 1

some animals can see in dim light, but ____ animal can see in complete darkness

Back 1

no

Front 2

light

Back 2

waves of electromagnetic energy that are between 380 and 760 nanometers in length

Front 3

infrared waves

Back 3

seen by rattlesnakes: too long for humans to see

Front 4

wavelength is to colour as intensity is to ________

Back 4

brightness

Front 5

sensitivity

Back 5

the ability to detect the presence of light

Front 6

acuity

Back 6

the ability to see the details of objects

Front 7

depth of focus

Back 7

a greater range of depths kept in focus on the retinas. (greater when the pupils are constricted

Front 8

when the level of illumination is too low to adequately activate the receptors, the pupils dilate to let in more light sacrificing

Back 8

acuity and depth of focus

Front 9

ciliary muscles

Back 9

adjusts the ligaments that hold the lens in place and helps it remain cylindrical

Front 10

whats the benefit? drawback of having both eyes on the same side of our head?

Back 10

-helps create visual depth 3D
-can't see everywhere without moving head

Front 11

binocular disparity

Back 11

the difference in the position of the image on the 2 retinas
-greater for close objects than for distant objects
-this makes it possible to construct a 3D image from 2D retinal images

Front 12

lateral communication

Back 12

communication across the major channels of sensory input

Front 13

In what way is the retina inside out?

Back 13

light reaches the receptor layer after passing though the 4 layers

Front 14

what are the two problems with the inside outness of the retina?

Back 14

incoming light is distorted by all of the retinal tissue
-the bundle of axons need to leave the eye, creating a blindspot

Front 15

fovea

Back 15

indentation about .33 cm at the center of the retina is the area of the retina that is speciallized for high acuity

Front 16

completion

Back 16

the way your visual system uses provide by the receptors around the blind spot to fill in the gaps in your retinal images

Front 17

surface interpolation

Back 17

the process by which we perceive surfaces. The visual system extracts info from around the edges and from it infers the appearance of large surfaces

Front 18

cones

Back 18

cone shaped receptors in the retina

Front 19

rods

Back 19

rod shaped receptors in the receptors

Front 20

duplexity theory of vision

Back 20

the theory that cones and rods mediate different types of vision: phototopic (cone) and scotoptopic (rod)

Front 21

phototopic vision

Back 21

predominates in good lighting and provides high acuity colour perceptions of the world

Front 22

scototopic vision

Back 22

when there is not enough light to excite the cones
-lacks the detail and the colour of phototopic

Front 23

phototopic spectral sensitivity curve

Back 23

relative brightness of different wavelengths of light shone over the fovea

Front 24

scototpic spectral sensitivity curve

Back 24

can be determined by asking subjects to judge the relative brightness of different waelengths of light shone on the periphery of the retina at an intensity too low to activate the cones that are located there.

Front 25

purkinje effect

Back 25

how bright yellows and reds look at compared to blue, and how grey they look in the darkness compared to the blue ones

Front 26

visual field

Back 26

the entire area that you can see at a particular moment

Front 27

it is because of ____ _____ that the world does not vanish mementarily when we blink

Back 27

temporal integration

Front 28

involuntary fixational eye movements: 3 and purpose

Back 28

tremors, drifts and saccades
if we fixated to perfectly our world would fade and dissapear because visual neurons respond to change
-

Front 29

visual transduction

Back 29

the conversion of light to neural signals by the visual receptors

Front 30

fixational eye movements

Back 30

enable us to see during fixation by keeping the images moving on the retina

Front 31

rhodospin

Back 31

red pigment in the rods that when exposed to lightm is bleached and loose its ability to absorb light and when returns to dark goes back to normal

Front 32

the degree to which rhodopsin absords _____ and is ______, predicts how humans see under the same condition

Back 32

light, bleached

Front 33

Rhodospin is a _______ coupled receptor that responds to light rather than to neurotransmitter molecules

Back 33

Gprotien

Front 34

when rods are in ______ their sodium channels are partially open, thus keeping the rods slightly depolarized and allowing a steady flow of excitatory glutamate neurotransmitter molecues to emanate from them

Back 34

darkness

Front 35

when rods are bleached or lightened, the sodium channels ________, hyperpolarizing the rods and reducing the release of glutamate

Back 35

close

Front 36

the transduction of light by rods exemplifies an important point: signals are often transmitted through neural systems by _______

Back 36

inhibition

Front 37

all signals from the left visual field reach the right primary visual cortex eiher ipsilatrally from the temporal hemiretina of the right eye or contralaterally via the optic chiasm from the ______ _____ of the left eye

Back 37

nasal heriretina

Front 38

retinotopic

Back 38

each lvel of the system is organized like a map of the retina.
-2 stimuli presented to adjacent areas of the retina excite adjacent neurons at all levels of the system.

Front 39

parvocellular layers

Back 39

they are composed of neurons with small cell bodies
-responsive to coloursfine pattern, and slow or stationary objects
-cones provide most imput
-

Front 40

magnocellurlar laters

Back 40

comosed of neurons with large cell bodies
-rods provide most imput

Front 41

the most important features of any visual display because the define the extent and position of objects

Back 41

edge perception

Front 42

on center cells

Back 42

respond to lights shone in the central region of the receptive field and to lights in the periphery with inhibition
this is followed by an "off" firing when the light is turned off

Front 43

off center cells

Back 43

opposite of on center
respond with inhbition and off firing responses to light shone in the middle of the receptive cells, and on to lights in the periphery

Front 44

the best way to increase firing rates of off and on center cells is too

Back 44

increase the contrast between the center and perphiery of the receptive field

Front 45

there are more complex cells than ___ cells

Back 45

simple

Front 46

how do complex cells differ from simple cells? 3pnts

Back 46

1 larger receptive fields
2 is not possible to divide the cepetive fields of complex cells into on or off because it responds to a particular straight edge stimulus of a particualar orientation regardless of its position in the receptive field
3 binocular (respond to either eye) not monocolur

Front 47

the correct word for colour

Back 47

hue

Front 48

black is an

Back 48

absence of light

Front 49

white is

Back 49

-roughly equal proportions of a wide range of wave lengths
-

Front 50

grey is

Back 50

the same wave lengths that make up white but at lower intensity

Front 51

component theory

Back 51

3 different type sof colour receptors (cones) each with different spectral sensitivity. colour is encoded by raioof activity in the cones

Front 52

opponent process theory

Back 52

2 clasess of cells for encoding colour and anotehr for encoding birghtness
-ie red would signal green by hanging its activity in the oter direction

Front 53

complementary colours

Back 53

produce white or gray when combined in equal measures

Front 54

trichromats

Back 54

most primates
-possess three color vision photopigments

Front 55

dichromats

Back 55

possessing 2 colour vision photopigments
-have difficulty seeing light at the red end
-lack photo pigment sensitive to long wave lengths

Front 56

colour constancy

Back 56

tendency for an object to stay the same color despite major changes in the wavelengths of light that it reflects
ie. blue shirt is still blue under flourescents or natural light
-maintainted as long as object is not in isolation

Front 57

retinex theory

Back 57

colour is determined by reflectance; the proportion of light of different wavelenghts that a surface reflects

Front 58

dual opponent colour cells

Back 58

in monkey visual cortex respond with vigorous on firing when the center of their ciruclar receptive field is illuminated with one wavelength

Front 59

cytochrome oxidase

Back 59

their distribution inthe primary visual cortex can be visualized if one stains slices of tissue with stains that have an affinity for this enzyme

Front 60

secondary visual cortex

Back 60

are those that receive most of their input from the primary visual corext

Front 61

visual association cortex

Back 61

those that receive input from areas of secondary visual cortex as a well as from the secondary areas of other sensory systems

Front 62

prestriate cortex

Back 62

band of tissue in the occipital lobe that surrounds the primary visual cortex

Front 63

inferotemporal cortex

Back 63

-inferotemporal lobe
-

Front 64

scotoma

Back 64

results from damage to an area of the primary visual cortex
an area of blindness

Front 65

hemianospic

Back 65

having a scotoma covering half of the visual field
-

Front 66

blindsight

Back 66

the ability of patients to respond to visual stimulus in their scotomas even though they are not aware of the stimuli
-basically, think they are jsut guessing