Term
| Problem of perception (3) |
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Definition
1. stimuli are ambiguous (many different stim. can cause same retinal image)
2. brain must make guesses to interpret
3. indirect because it requires information processing |
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Term
| Levels of understanding perception (3 names) |
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Definition
1. ecological/computational
2.psychological
3. physiological |
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Term
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Definition
-level of understanding perception
what is GOAL of perception, and what properties of the stimulus allow the problem to be solved?
ex: moving retinal picture shows we are moving |
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Term
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Definition
level of understanding perception
what processes underlie our perception, and what representations they lead to. |
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Term
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Definition
level of understanding perception
how the processes and representations are realized by the nervous system |
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Term
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Definition
| studying perceptual deficits in patients with brain damage |
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Term
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Definition
| examine which parts of the brain are active during a perceptual task by measuring blood flow |
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Term
| electrical potentials (measure) |
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Definition
| examine brain responses to stimuli by measuring electrical responses on scalp |
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Term
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Definition
| measure responses of individual cells by recording their electrical signals |
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Term
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Definition
| study perception by imaging brain activity |
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Term
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Definition
-cell body (machinery to keep cell functioning)
-dendrites - fibers that RECEIVE info
-axon- fiber to SEND info
-synapse- where neurons meet |
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Term
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Definition
| signal through electrical activity controlled by the flow of charged ions across the cell membrane, leading to charge differences. |
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Term
| electric potentials (3 types) |
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Definition
-resting potential
-graded potential
-action potential |
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Term
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Definition
| baseline charge difference when cell is at rest |
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Term
| graded potential (def +2 types) |
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Definition
passive charge difference in response to stimulation
-synaptic potential - due to influence of other neuron
-receptor potential - due to PHYSICAL stimulus (like light absorption) |
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Term
| differences between action and graded potentials (5) |
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Definition
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size
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AP
large fixed
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GP
small variable
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duration
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brief
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long
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signal
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depolar ONLY
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depolar OR hyperpolar
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location
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axon
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throughout cell
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purpose
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carry fixed signal long distances
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sum togther input from other cells
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Term
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Definition
-connection between neurons mediated by chemical neurotransmitters
-can be excitatory or inhibitory on post-synaptic cell
-receptive fields depend on pattern of synaptic connections to cell |
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Term
| How neurons carry info (3 ways) |
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Definition
1. size of the response (graded or # of action potentials)
2. pattern of responses
3. pattern of connections |
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Term
| physiological approaches to perception (4) |
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Definition
-neuropsychology
-neuroimaging
-electrical potentials
-single unit recording |
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Term
| introspection (def, 2 problems, 2 examples) |
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Definition
-"thinking" about one's own perceptual experience
-subjective, may not reveal underlying processes
-color opponency (red/green), lateral inhibition (Mach bands) |
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Term
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Definition
| weakest stimuli we can detect or tell apart, high threshold means LOW sensitivity |
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Term
| Problems with Thresholds (4) |
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Definition
1. limited by noise (not all or none)
2. detection depends on BOTH sensitivity and criterion
3. signal detection theory provides uncertainty
4. criterion-free measures (like forced choice) are more direct |
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Term
| sensory channel (3 traits) |
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Definition
-"filter" that only responds for certain info (orientation channel only responds to certain tilts)
-can be measured by measuring how TWO stimuli interact
-IF two stim. influence each other, they are encoded by SAME channel |
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Term
| reaction times (def and use) |
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Definition
measure of the speed of a response
-used to infer type of processing involved |
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Term
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Definition
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Term
| cornea and lens (function) |
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Definition
| focus light to form image on the retina |
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Term
| retina (def and function) |
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Definition
| thin layer of neurons along back of eye that absorb, process and transmit info about the light image |
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Term
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Definition
| small region of retina specialized for finest vision, corresponds to center of gaze |
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Term
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Definition
| receptor-free "hole" in retina where ganglion axons leave eye |
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Term
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Definition
| convert physical energy into electrical signal |
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Term
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Definition
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Cones
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Rods
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light sensitivity
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low
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high
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operating range
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moderate-bright
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dim light
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spatial acuity
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high
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low
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retinal distrib.
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peak in fovea
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peak ~20 deg
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# of receptor types
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3
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1
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color vision
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yes
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no
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Term
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Definition
| area on the retina to which a cell responds |
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Term
| bipolar cell receptive fields (3 traits) |
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Definition
-center-surround cells, on or off centered
-similar to ganglion cells
-emphasize contrast |
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Term
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Definition
| inhibition between spatially adjacent cells |
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Term
| Paths of info flow in retina (2) |
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Definition
1. straight through
receptor -> bipolar->ganglion
2.sideways, via horizontal and amacrine cells |
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Term
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Definition
1. most ganglion cells send their axons to LGN
2.Nasal fibers cross over- CONTRALATERAL
3. 2 layers- magno- and parvocellular
4. center-surround and monocular |
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Term
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Definition
1. most LGN cells send their axons
2. orientation selectivity
3. inc. selectivity for size
4.BINOCULAR
5. sensitivity to direction of movement |
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Term
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Definition
-parvocellular (color and fine detail)
-magnocellular (motion) |
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Term
| Magnocellular vs Parvocellular (3) |
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Definition
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Magnocellular
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Parvocellular
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sens. to color
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low
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high
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sens. to fine detail
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low
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high
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sens. to motion and rapid changes
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high
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low
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Term
| Receptive field of receptor |
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Definition
0 + 0
Light must fall at specific point to excite |
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Term
| receptive field of POST receptoral cell |
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Definition
0 - + - 0
light in center vs surround have OPPOSITE effects |
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Term
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Definition
| receptor-horiz-bipolar circuit |
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Term
| problem of color constancy |
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Definition
| we want to "see" color of OBJECTS, but wavelength reaching eye depends on BOTH object and lighting (emitted vs reflected light) |
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Term
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Definition
wavelength affects SIZE of response, not FORM of response
MEANS- any single cone can't tell the difference between change in wavelentgh or change in intensity |
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Term
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Definition
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Term
| implication of color matching experiments |
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Definition
| one receptor type can match ANY light by varying intensity of ONE primary light, so on for two |
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Term
| Monochromats vs dichromats vs trichromats |
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Definition
| one receptor type (rod vision), two cone types, three cone types |
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Term
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Definition
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S cones
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M&L
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numbers
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few
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most cones
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function
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mainly color
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color AND form
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genetics
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autosomal
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sex-linked
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Term
| S cones signal _____ but NOT _____ |
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Definition
| signal color but NOT LUMINANCE |
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Term
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Definition
-Trichromacy- BASED on color matching
-DEPENDS on receptors
-Opponency BASED on color appearance
DEPENDS on post-receptoral cells |
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Term
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Definition
| Third photopigment (M) helps to detect ripe fruit |
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Term
| Hering's Opponent Color theory (3) |
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Definition
3 opponent channels:
1. red/green
2. Blue/yellow
3. bright/ dark |
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Term
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Definition
| the idea that a color can be mutually exclusive (ie can't be BOTH red and green) |
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Term
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Definition
| angle a color is from grey |
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Term
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Definition
| how pure a color looks (distance from grey) |
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Term
| Which cells SHOW color opponency? |
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Definition
| post-receptoral ganglions |
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Term
| Pysiological evidence for color opponency (2) |
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Definition
-response of LGN or ganglion cells to different wavelengths
-different cone types connect to center and surround of RF (gives color and space opponence) |
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Term
| Color spectrum is PHYSICALLY _____, but _____ categorized |
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Definition
| physically continuous, psychologically categorized |
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Term
| language/cultural differences (4) |
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Definition
1. different languages apply color terms to SIMILAR regions
2. implies color perception is UNIVERSAL
3. universality might result from common physiology
4. weak influence of culture on color perception |
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