9: VISION Flashcards
1
Q
STIMULUS of VISUAL SYSTEM
A
LIGHT
2
Q
narrow band on light spectrum of electromagnetic radiation w wavelength btwn 380-760 mm
A
VISIBLE LIGHT TO HUMANS
3
Q
Bees can detect ____ on the spectrum of electromagnetic radiation
A
UV RADIATION
4
Q
3 DIMENSIONS THAT DETERMINE PERCEIVED COLOUR OF LIGHT
A
- HUE
- SATURATION
- BRIGHTNESS
5
Q
dimension of light determined by WAVELENGTH
A
HUE
6
Q
dimension of light that = relative PURITY of light
A
SATURATION
7
Q
dimension of light that = INTENSITY of light
A
BRIGHTNESS
8
Q
relative constant appearance of colours of objects viewed under varying lighting conditions
A
COLORU CONSTANCY
9
Q
SHORTER wavelengths = ___ freq
LONGER wavelengths = ___ freq
A
HIGHER; LOWER
10
Q
specialized neuron that detects participate category of physical events
A
SENSORY RECEPTORS
11
Q
neural tissue + photoreceptive cells located on inner surface of back of eye
A
RETINA
12
Q
opaque white outer layer of most of eye that does NOT let light into eye
A
SCLERA
13
Q
transparent outer layer at front of eye
A
CORNEA
14
Q
opening in IRIS that regulates amt of light that enters eye (based on its size)
A
PUPIL
15
Q
pigmented ring of muscles behind CORNEA
A
IRIS
16
Q
series of transparent/onionlike layers behind IRIS that changes shape from contractions of CILIARY MUSCLES that permit eye to focus images of near/distant objects on RETINA
A
LENS
17
Q
RETINA + OPTIC NERVES = in ___ (CNS or PNS)
A
CNS
18
Q
changes in thickness of LENS that focuses images of near/distant objects on RETINA
A
ACCOMMODATION
19
Q
receptor cells of RETINA that transduce PHOTIC ENERGY into ELECTRICAL POTENTIALS
A
PHOTORECEPTORS
20
Q
2 TYPES OF PHOTORECEPTOR CELLS
A
- RODS
- CONES
21
Q
- most prevalent in CENTRAL RETINA (found in FOVEA)
- sensitive to MODERATE-HIGH levels of light
- for DAYTIME/COLOUR vision
- provide info abt HUE
- provide EXCELLENT acuity
A
RODS
22
Q
- most prevalent in PERIPHERAL RETINA (NOT in FOVEA)
- sensitive to LOW levels of light
- for NIGHT vision
- provide only MONOCHROMATIC info (B+W)
- provide POOR acuity
A
CONES
23
Q
RODS + CONES contain ___ that provide input to ___ + ___ CELLS
A
PHOTOPIGMENTS; BIPOLAR + HORIZONTAL
24
Q
protein dye bonded to RETINAL (substance derived from vitamin A) which = responsible for TRANSDUCTION of visual info
A
PHOTOPIGMENTS
25
PHOTORECEPTORS + BIPOLAR CELLS ___ (do/do not) produce ACTION POTENTIALS
DO NOT
26
idea that a bunch of cells at back of eye converge into smaller + smaller number of cells that process what we're looking at
CONVERGENCE
27
2 MAIN CELLULAR LAYERS OF RETINA
1. PHOTORECEPTIVE LAYER
2. BIPOLAR LAYER
3. GANGLION CELL LAYER
28
central region of RETINA w GREATEST VISUAL ACUITY
FOVEA
29
how well a person can FOCUS on an object
VISUAL ACUITY
30
Which type of PHOTORECEPTOR = found in FOVEA
CONES
31
point where fibres of GANGLION CELLS that form OPTIC NERVE exit RETINA
OPTIC DISK
32
what part of RETINA = responsible for BLINDSPOT?
OPTIC DISK
33
cells in MIDDLE layer of RETINA that convey info from PHOTORECEPTORS to GANGLION CELLS
BIPOLAR CELLS
34
cells that:
- receive info from BIPOLAR CELLS
- their axons give rise to OPTIC NERVE
- carry visual info to rest of brain
GANGLION CELLS
35
cells that interconnect adjacent PHOTORECEPTORS + outer processes of BIPOLAR CELLS
HORIZONTAL CELLS
36
cells that interconnect adjacent GANGLION CELLS + inner processes of BIPOLAR CELLS
AMACRINE CELLS
37
part of visual field that individuals neuron sees
RECEPTIVE FIELD
38
RECEPTIVE FIELD = portion of visual field in which presentation of visual stimuli will produce an ___ in ___ ___ of particular neuron
ALTERATION; FIRING RATE
39
What does LOCATION of RECEPTIVE FIELD of a neuron depend on?
LOCATION OF PHOTORECEPTORS that provide visual info
40
vision that involves seeing w only 1 eye at a time
MONOCULAR VISION
41
vision that involves seeing w BOTH eyes at same time
BINOCULAR VISION
42
pathway of visual processing from RETINA → LATERAL GENICULATE NUCLEUS → STRIATE/EXTRASTRIATE CORTICAL REGIONS
VISUAL PATHWAY
43
RETINA → OPTIC NERVE → OPTIC CHIASM → OPTIC TRACT → DORSAL LAT GENICULATE NUCLEUS → OPTIC RADIATIONS → STRIATE VISUAL CORTEX
ORDER OF VISUAL PATHWAY
44
bundles of axons from retinal GANGLION CELLS that exit eye + convey info to LATERAL GENICULATE NUCLEUS
OPTIC NERVE
45
point where OPTIC NERVES join together to form an X-SHAPE after which some nerves stay on same side + others cross over to opposite side of brain
OPTIC CHIASM
46
axons from GANG CELLS serving INNER (NASAL) halves of RETINA _________ where as axons from OUTER halves of RETINA _________
cross thru OPTIC CHIASM + ascend to DORSAL LAT GENIC NUCLEUS on OPPOSITE side of brain; remain on SAME side of brain
47
group of cell bodies that receives inputs from RETINA + projects them to PRIMARY VISUAL CORTEX
DORSAL LATERAL GENICULATE NUCLEUS (LGN)
48
neurons in LGN send axons thru ____ _____ to PRIMARY VISUAL CORTEX
OPTIC RADIATIONS
49
How many layers does LGN have?
6
50
cortex that sends visual info to VISUAL ASSOCIATION CORTEX
V1/PRIMARY VISUAL CORTEX/STRIATE CORTEX
51
second cortical area for vision processing that receives fibres from STRIATE CORTEX + form SUPERIOR COLLICULI + projects to INFERIOR TEMPORAL CORTEX
V2/VISUAL ASSOCIATION CORTEX/EXTRASTRIATE CORTEX
52
layers _/_/_ of LGN receive input from CONTRALAT eye
1/4/6
53
layers _/_/_ of LGN receive input from IPSILAT eye
2/3/5
54
2 TYPES OF LAYERS/PROJECTIONS OF LGN
1. MAGNOCELLULAR LAYERS (M PATHWAYS)
2. PARVOCELLULAR LAYERS (P PATHWAYS)
55
- LARGE gang cells
- INNER 2 layers of neurons of LGN
- colour INSENSITIVE
- LARGE receptive field
- HIGH contrast sensitivity
ATTRIBUTES OF MAGNOCELLULAR LAYERS
56
- SMALL gang cells
- OUTER 4 layers of neurons of LGN
- colour SENSITIVE
- SMALL receptive field
- LOW contrast sensitivity
ATTRIBUTES OF PARVOCELLULAR LAYERS
57
SPATIAL RES: transmits info necessary for perception of FORM/MVMT/DEPTH/SMOL DIFFS IN BRIGHTNESS to V1
TEMPORAL RES: FAST + TRANSIENT response
SPATIAL + TEMPORAL RESOLUTION OF MAGNOCELLULAR LAYERS
58
SPATIAL RES: transmits info necessary for perception of COLOUR/FINE DETAILS to V1
TEMPORAL RES: SLOW + SUSTAINED response
SPATIAL + TEMPORAL RESOLUTION OF PARVOCELLULAR LAYERS
59
What is the 1st cortical region involved in combining visual info from several sources?
STRIATE CORTEX
60
Which type of cells encode info abt relative amts of light falling on CENTER/SURROUND regions of their RECEPTIVE FIELDS?
GANGLION CELLS
61
organization in which neurons w receptive fields CLOSE TOGETHER in visual space have cell bodies CLOSE TOGETHER in cortex
RETINOTOPIC ORGANIZATION OF STRIATE VISUAL CORTEX
62
cells that initiate signals to GANG CELLS that = important in perceiving LIGHT/DARK
ON/OFF BIPOLAR CELLS
63
mammalian GANG CELLS have receptive field that consists of ___/___
CENTER/SURROUND
64
3 TYPES OF GANG CELLS
1. ON CELLS
2. OFF CELLS
3. ON/OFF CELLS
65
type of GANG CELL EXCITED by light falling on CENTRE + INHIBITED by light falling in SURROUND (signal INCR in illumination)
ON CELLS
66
type of GANG CELL EXCITED by light falling in SURROUND + INHIBITED by light falling on CENTRE (signal DECR in illumination)
OFF CELLS
67
type of GANG CELLS that = briefly EXCITED when light = turned ON/OFF
ON/OFF CELLS
68
idea that diff types of cells = TUNED to respond to diff aspects of visual info
TUNING
69
2 COLOUR THEORIES
1. TRICHROMATIC (3 COLOUR) THEORY
2. OPPONENT-COLOUR SYSTEM THEORY
70
colour theory that suggests that eye can detect diff colours bc it contains 3 TYPES OF CONES each sensitive to a single hue
TRICHROMATIC (3 COLOUR) THEORY
71
3 DIFF COLOURS OF CONES IN TRICHROM THEORY
BLUE/GREEN/RED
72
colour theory that suggests that colour might be represented in visual system as OPPONENT COLOURS
OPPONENT-COLOUR SYSTEM THEORY
73
type of cells involved in OPPONENT-COLOUR SYSTEM THEORY that respond specifically to PAIRS of primary colours
GANGLION CELLS
74
2 KINDS OF COLOUR-SENSITIVE GANG CELLS
1. RED-GREEN
2. YELLOW-BLUE
75
- when part of receptive field = illuminated w colour shown → cell's firing rate INCR
- when part of receptive field = illuminated w complementary colour → cell's firing rate DECR
CENTER-SURROUND ORGANIZATION OF COLOUR-SENSITIVE GANG CELLS
76
- axon that signals red/green or yellow/blue can either INCR/DECR its rate of firing but CANNOT do both at same time
- REDDISH GREEN would have to be signalled by GANAG CELL firing SLOWLY/RAPIDLY at same time which = IMPOSSIBLE
REASON WHY WE CANNOT PERCEIVE REDDISH GREEN COLOURA
77
order of info abt relative amts of light falling on CENTER/SURROUND that = transferred from GANG CELLS
LGN → STRIATE CORTEX → EXTRASTRIATE CORTEX
78
How many layers does the STRIATE CORTEX have?
6
79
at which layer of STRIATE CORTEX is input from MAGNO/PARVOCELLULAR systems processed?
4TH LAYER
80
idea that brain would weigh over 30K lbs if whole visual field had as many neurons dedicated to it as are dedicated to FOVEA
DISPROPORTIONATE REPRESENTATION OF FOVEA
81
cells in STRIATE CORTEX = sensitive to specific ____
ORIENTATIONS
82
relative width of bands in SINE-WAVE GRATING measured in cycles per degree of visual angle
SPATIAL FREQUENCY
83
cells in STRIATE CORTEX = tuned to specific ___ ___
SPATIAL FREQS
84
series of straight parallel bands varying continuously in brightness according to a sine-wave function along a ling perpendicular to their lengths
SINE-WAVE GRATING
85
image that = DEFICIENT in HIGH freq info = ____/____
FUZZY/OUT OF FOCUS
86
most important info = contained in ___ SPATIAL FREQS
LOW
87
when LOW FREQ info = REMOVED: ____ of images = HARD to perceive
SHAPES
88
when HIGH FREQ info = REMOVED: ___ ___ of images = ELIMINATED
SHARP EDGES
89
GENDER of a person in an image can be determined from ___ freq images but determining IDENTITY of a person in an image requires ___ freq images
LOW; HIGH
90
1. V4
2. MIDDLE TEMPORAL AREA (MT)
3. FUSIFORM FACE AREA (FFA)
4. PARAHIPPOCAMPAL PLACE AREA (PPA)
5. INFERIOR TEMPORAL CORTEX (IT)
5 MODULES IN VISUAL SYSTEM
91
module sensitive to COLOUR
V4
92
module sensitive to MOTION
MIDDLE TEMPORAL AREA (MT)
93
module sensitive to FACE PERCEPTION
FUSIFORM FACE AREA (FFA)
94
module sensitive to PLACE RECOGNITION
PARAHIPPOCAMPAL PLACE AREA (PPA)
95
module sensitive to OBJECT RECOGNITION
INFERIOR TEMPORAL CORTEX (IT)
