Chapter 6: Vision Flashcards
(152 cards)
1
Q
Sensation/Perception involves cells of the nervous system that are specialized to detect stimuli from the environment.
A
Sensation
2
Q
Sensation/Perception is the conscious experience and interpretation of information from the sense
A
Perception
3
Q
The _________ in the eye detect visible light.
A
photoreceptors
4
Q
For humans, visible light is a narrow band of the spectrum of ________________ ________
A
electromagnetic radiation
5
Q
What are the three dimensions of light?
A
Hue, brightness, saturation
6
Q
Hue depends on the _______ of light
A
wavelength
7
Q
Brightness depends on the _______ of light
A
intensity
8
Q
Saturation depends on the ________ _____ of light
A
relative purity
9
Q
The longer end of the visible light spectrum is _____.
A
red
10
Q
The shorter end of the visible light spectrum is ______.
A
purple
11
Q
We receive information about the environment from _______ ________.
A
Sensory receptors
12
Q
Stimuli are detected by sensory receptors in the process known as ________ __________.
A
sensory transduction
13
Q
The image must be focused on the _____ in order for us to see.
A
retina
14
Q
_____ regulate the amount of light entering the eye.
A
Pupils
15
Q
The ____ is responsible for accommodation.
A
lens
16
Q
The ______ bends the light so that it hits the retina.
A
cornea
17
Q
The retina contains two kinds of photoreceptors that detect light: _______ and ______
A
rods; cones
18
Q
Three cellular layers of the retina (from deep to shallow):
A
Photoreceptive
Bipolar
Ganglion cell
19
Q
True or false: There are more cones than rods in the retina
A
False, there are around 120million rods and only 6million cones
20
Q
Rods/cones work under low intensity light
A
Rods
21
Q
Rods/cones are responsible for acuity and color vision
A
Cones
22
Q
The fovea contains only rods/cones
A
cones
23
Q
The ______ ____ at the back of the eye has no receptors, causing a blind spot.
A
optic disk
24
Q
Transduction
A
The process by which energy from the environment is converted to a change in membrane potential in a neuron.
25
The first step in visual perception is ______.
Transduction
26
___________ are responsible for transduction of light energy into changes in membrane potential
Photopigments
27
Molecules that make up a photopigment:
Opsin
Retinal
28
When photoreceptors experience darkness, they depolarize/hyperpolarize
depolarize
29
When photoreceptors experience light, they depolarize/hyperpolarize
hyperpolarize
30
The ON center bipolar cells are depolarized/hyperpolarized by glutamate
hyperpolarized
31
The OFF center bipolar cells are depolarized/hyperpolarized by glutamate
depolarized
32
The ON/OFF center bipolar cells synapse with the ________ and influence the rate of firing; they do not fire themselves.
ganglion cells
33
The place where a visual stimulus must be located to produce a response in a neuron is the _____________ ____.
receptive field
34
The location of a receptive field of a particular neuron depends on the location of the ___________ that provide it with visual information.
photoreceptors
35
At the fovea/periphery of the retina, many individual receptors converge on a single ganglion cell.
periphery
36
Why is our foveal vision very acutes while our peripheral vision is less precise?
Because the receptor-to-axon ratio is small in the fovea (1:1, e.g.) and large in the peripheral (6:1, e.g.)
37
Three types of eye movements:
Vergence
Saccadic
Pursuit
38
Describe vergence eye movements
cooperative movements that keep both eyes fixed on the same target
39
Describe saccadic eye movements
Shifting your gaze abruptly from one point to another
40
Describe pursuit eye movements
Eye moves smoothly as it focuses on a moving object
41
At the back of each eye, axons of the retinal ganglion cells bundle together to form the _______ ______.
optic nerve
42
The optic nerves convey information from the retina to the _________ of the thalamus.
Dorsal lateral geniculate nucleus (LGN)
43
The optic nerves join together at the base of the brain to form the X-shaped _______ ______.
Optic chiasm
44
Where do the axons from ganglion cells serving the nasal sides of the retina go?
They cross through the optic chiasm and ascend to the LGN on the opposite side of the brain
45
Where do the axons from ganglion cells serving the temporal sides of the retina go?
They remain on the same side of the brain.
46
True or False: Because the axons from the nasal halves of the retinas cross to the other side of the brain, each hemisphere receives information from the contralateral half of the visual scene.
True -- the right hemisphere receives info from the left half of the visual field and vice versa.
47
The phenomenon in which cortical regions involved in conscious perception of visual stimuli are damaged, but other visual pathways that are not involved in conscious perception are intact.
Blindsight
48
The journey of information from light detection in the retina to the experience of complex visual scenes occurs along the ______ _______.
visual pathway
49
The visual pathway:
Photoreceptors of retina --> bipolar and retinal ganglion cells --> optic nerves --> LGN --> Primary visual cortex (V1) --> Visual association cortex (V2) --> may continue on to V3, V4, V5
50
The neurons in the LGN send their axons through ______ _______ to the V1.
optic radiations
51
The primary visual cortex is also called the _____ cortex.
striate
52
The visual association cortex (V2) is also called the ________ cortex.
extrastriate
53
Blindsight occurs when the cortical regions involved in ______ _________ are damaged but other pathways remain intact.
conscious perception
54
The LGN contains _ layers of neurons
6
55
Layers 1, 4, and 6 of the LGN receive input from the ipsilateral/contralateral eye
contralateral
56
Layers 2, 3, and 5 of the LGN receive input from the ipsilateral/contralateral eye
ipsilateral
57
The inner two layers of the LGN (1 and 2) are called the ________ layers.
magnocellular
58
The outer four layers of the LGN are called the ________ layers
parvocellular
59
A third set of neurons in the LGN called the __________ ________ are found below each of the magnocellular and parvocellular layers.
Koniocellular sublayers
60
Hubel and Wiesel discovered that neurons in the visual cortex did not simply respond to spots of light; they selectively respond to specific _______ of the visual world
features/contours
61
The ______ cortex performs additional processing of information from the LGN and transmits it to the extrastriate cortex
striate
62
A large portion of the striate cortex is devoted to the analysis of info from the ______.
Fovea, the smallest part of the visual field
63
The striate cortex consists of _ layers arranged in bands perpendicular/parallel to the surface.
6; parallel
64
The _th layer of the striate cortex is divided into four sublayers.
4th
65
In the striate cortex, info from color-sensitive ganglion cells is transmitted, through the parvocellular and koniocellular layers of the LGN, to special cells grouped together in _______ ______ _____.
cytochrome oxidase blobs
66
CO blobs are found in layers _, _, _, and _ of the striate cortex.
2,3,5,6
67
The distribution of CO-rich neurons in the extrastriate cortex consists of three kinds of stripes:
Thick, pale, thin
68
Neurons in CO blobs of striate cortex project to ___ stripes
Thin
69
Neurons outside the CO blobs in the interblob areas project to ______ stripes and _____ stripes of the extrastriate cortex
thick; pale
70
Neurons in the thin stripes receive information concerning _____.
Color
71
Neurons in the thick and pale stripes receive information about ________, ____ ______, ______, and ____ _____.
orientation, spatial frequency, movement, retinal disparity
72
The striate cortex is divided into around 2,500 ______ containing about 150,000 neurons
modules
73
True or false: Each module of the striate cortex is devoted to the analysis of various features contained in one very small portion of the visual field.
True
74
The input from the koniocellular sublayers of the LGN is received by sublayers __ and __ in the striate cortex.
2,3
75
Magnocellular input is received by sublayer ____ of the striate cortex.
4C-alpha
76
Parvocellular input is received by sublayer ____ of the striate cortex
4C-beta
77
The modules of the striate cortex contain _ segments, each surrounding a ___ _____.
2; CO blob
78
Neurons located within the CO blobs of the striate cortex are sensitive to _____ and their receptive fields are _________.
color; monocular
79
In the interblob regions of the striate cortex, neurons show sensitivity to ________, _______, and _______ _______, not color (usually).
orientation, movement, binocular disparity
80
True or false: The striate cortex is necessary for visual perception, including the perception of objects and of entire visual scenes
FALSE, loser. Each of the 1000s of modules of the striate cortex only see a tiny part of the visual field. It's the extrastriate cortex's job to combine this information into entire visual scenes. Let's go.
81
The primate extrastriate cortex consists of _ additional regions labeled _-_, each of which contain neurons that respond to particular features.
4; V2-V5
82
True or false: the extrastriate cortex receives information from "lower" regions and then passes this info to "higher" regions for further analysis
True; all hail the hierarchy
83
Visual processing in the extrastriate cortex divides into two pathways:
Dorsal Stream
Ventral Stream
84
The ventral stream of the extrastriate cortex begins with neurons in the _____ and ____ stripes of area V2, continues forward to area ___, and then projects to a variety of subareas of the _______ _______ ______.
pale; thin; V4; inferior temporal cortex
85
The dorsal stream of the extrastriate cortex begins with the neurons in the____ stripes of area V2 and ascends into regions of the ________ ________ ______.
Thick; posterior parietal cortex
86
The dorsal stream of the extrastriate cortex processes where object is _____ and the ____ and _____ of movement
Located; speed; direction
87
The ventral stream of the extrastriate cortex processes _________ and its _____
what an object is and its colors
88
The _____________ region is specifically activated by photographs, silhouettes, or stick drawings of human bodies or body parts.
Extrastriate body area
89
Research by Melvyn Goodale and colleagues indicates that the primary function of the dorsal stream of the visual cortex is to
provide feedback to guide actions
90
When light strikes a molecule of photopigment, the membrane potential undergoes a depolarization/hyperpolarization, which in turn ________.
hyperpolarization; reduces release of an inhibitory neurotransmitter onto the bipolar cell
91
Disparity-sensitive neurons in the ______________ stream respond to large, extended visual surfaces.
Dorsal
92
ON cells are excited/inhibited by light falling in the central field (center) and excited/inhibited by light falling in the surrounding field (surround)
excited;inhibited
93
OFF cells are excited by light falling in the center/surround and inhibited by light falling in the center/surround
surround; center
94
ON/OFF ganglion cells are briefly excited when light is turned ______
On or off.
95
Rod bipolar cells are all of the __ ganglion cell type.
ON
96
In trichromatic coding, the eye detects different colors because _______.
it contains three types of receptors, each sensitive to a single hue (red, green, blue).
97
Genetic defects in color vision result from anomalies in 1+ of the three types of _____.
cones
98
People with protanopia often confuse the colors red and green because ___________.
their red cones are filled with green cone opsin.
99
People with deuteranopia confuse the colors red and green because _____.
their green cones are filled with red cone opsin.
100
Those with ________ and ________ confuse red and green.
protanopia; deuteranopia
101
Those with tritanopia see the world in _____ and ______ because _____.
reds and greens; their retina lacks a blue cone
102
Those with monochromatic vision lack ______ altogether.
cones
103
The retina contains two kinds of color-sensitive ganglion cells: ____-_______ and _____-____.
red-green; yellow-blue
104
The other ganglion cells in the retina are ______ detectors. They encode relative brightness in the center and surround, not color.
black-and-white
105
Red light excites red cones, which causes the excitation/inhibition of red-green cells.
excitation
106
Green light excites green cones, which causes the excitation/inhibition of red-green cells
inhibition
107
Yellow light excites red and green cones equally, which causes the excitation/inhibition of yellow-blue cells.
excitation
108
Blue light excites/inhibits the activity of yellow-blue cells.
inhibits
109
Why can't we perceive a reddish green or a bluish yellow?!
An axon that signals red, green, yellow, or blue, can either increase or decrease its rate of firing; it cannot do both at the same time. In order to perceive a reddish green, the red-green ganglion cell would have to fire slowly and rapidly at the same time.
110
Complementary colors are those that make ____ when added together.
White
111
What causes negative afterimages?
When a ganglion cells is excited or inhibited for a prolonged period of time, they later show a rebound effect, firing faster or slower than normal.
112
In the striate cortex, the parvocellular system receives information only from what color cones?
Red and green
113
In the striate cortex, the koniocellular system receives information from what color cones?
Blue
114
Cells in the ______ system show high spatial resolution and low temporal resolution, providing information about fine details.
Parvocellular
115
True or false: The koniocellular system provides information about fine details.
False, it does not.
116
True or false: The neurons in the magnocellular system are color-blind.
True, just like that Counting Crows song. : )
117
The dorsal/ventral stream receives input mostly from the magnocellular system.
dorsal
118
The dorsal/ventral stream receives approximately equal input from the magnocellular and the parvocellular/koniocellular systems.
Ventral
119
Our visual system will compensate for the source of the light by simultaneously comparing the color composition of each point in the visual field with the average color of the entire scene.
Color constancy
120
Lesions of a restricted region of the human extrastriate cortex can cause loss of color vision without the disruption of visual acuity, called _______ ________.
Cerebral achromatopsia
121
Sharp edges contain high/low spatial frequencies.
high
122
Large areas of light and dark are represented by high/low spatial frequencies
low
123
The recognition of visual patterns and identification of particular objects takes place in the ______ ______ cortex.
inferior temporal
124
The inferior temporal cortex consists of two major regions:
TEO (posterior)
TE (anterior)
125
Visual agnosia is caused by damage to parts of the _________ ______ that contribute to the ______ _____.
extrastriate cortex; ventral stream
126
The size of the ________ ____ also grows as the V1-V5 hierarchy is ascended.
receptive fields
127
The inferior temporal cortex is located at the end of the _____ stream.
ventral
128
The receptive fields of neurons in area TE are the smallest/largest of them all.
largest
129
What is the function of the inferior temporal cortex?
Form, color, 3-D perception
130
Those with visual agnosia are usually unable to _____________, although _______.
identify common items by sight, although visual acuity remains
131
The _____ _____ _____ is a relatively large region of the ventral stream of the visual association cortex that responds to a wide variety of objects and shapes.
Lateral occipital complex (LOC)
132
Prosopagnosia
inability to recognize particular faces
133
The fusiform face area is devoted to ____ recognition and is located on the base of the _____ lobe.
facial; temporal
134
The _________ ___ ____, located in the limbic cortex, is activated by the sights of scenes and backgrounds.
parahippocampal place area (PPA)
135
True or false: Because of the extensive experience we have of seeing people's faces, we can become expert at recognizing them.
True
136
Binocular vision provides a vivid perception of depth through the process of stereoscopic vision, or _______.
stereopsis
137
Most neurons in the striate cortex are monocular/binocular and respond to _____ ______.
binocular; retinal disparity
138
Disparity-sensitive neurons are found in the ventral/dorsal stream
dorsal
139
Retinal disparity
a stimulus that produces images on slightly different parts of the retina of each eye.
140
The disparity-sensitive neurons found in the dorsal stream (which is involved in spatial perception) respond to _____, _____ visual surfaces.
large, extended
141
The _______ lobe is involved in spatial and somatosensory perception, and it receives visual, auditory, somatosensory, and vestibular information to perform these tasks.
parietal
142
The dorsal stream of the extrastriate cortex terminates in the _____ ______ cortex.
Posterior parietal
143
5 regions within the intraparietal sulcus (IPS):
AIP
LIP
VIP
CIP
MIP
144
Parts of the IPS involved in visual attention and control of saccadic eye movements
LIP
VIP
145
Parts of the IPS involved in visual control of reaching and pointing
VIP
MIP
146
Parts of the IPS involved in visual control of grasping and manipulating hand movements
AIP
147
Parts of the IPS involved in perception of depth from stereopsis
CIP
148
True or false: Most neurons in the striate cortex are sensitive to orientation.
True
149
True or false: In the striate cortex, if a line or edge is positioned in the cell's receptive field and rotated around its center, the cell will respond only when the line is in a particular orientation.
True
150
Area __ of the extrastriate cortex (area MT, for medial
temporal) contains neurons that respond to movement
V5
151
Area ___ receives information about movement from V5, which helps to analyze optic flow.
MST (medial superior temporal)
152
Bilateral damage to area V5 produces an inability to perceive movement
akinetopsia
