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Sensation & Perception 1
Introduction to Perception, Vision, and the Visual Cortex (chs. 1-4)
235
Psychology
Undergraduate 4
09/24/2011

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Term
Sequence of processes working together to determine experience of / reaction to stimuli in environment
Definition
Perceptual process
Term
Stimulus in center of attention
Definition
Attended stimulus
Term
Network of light-sensitive receptors and other neurons lining back of eye
Definition
Retina
Term
____ transform energy from environment into electrical system; this is called _____
Definition

Receptors;

 

transduction

Term
Transformation of one form of energy into another; energy in environment --> electrical energy
Definition
Transduction
Term
Image transformed into electrical signals in receptors, which activate other neurons --> other neurons --> out of eye and transmitted to brain
Definition
Transmission
Term
Interactions between neurons (related to transmission and happen at same time)
Definition
Neural processing
Term
Conscious sensory experience
Definition
Perception
Term
Ability to place object in category
Definition
Recognition
Term
Inability to recognize objects
Definition
Visual [form] agnosia
Term
Any information perceiver brings to situation; example
Definition
Knowledge; rat-man demonstration
Term
Processing based on incoming data, essential for perception because process begins with stimulation of receptors
Definition
Bottom-up processing (working UP the system from external object reflected on receptors to perceptual experience)
Term
Processing based on knowledge
Definition
Top-down processing (knowledge-based)
Term
Put following in order:

Transmission, Recognition, Environmental Stimulus, Transduction, Stimulus on the Receptors, Perception, Attended Stimulus, Processing, Action
Definition
Environmental Stimulus, Attended Stimulus, Stimulus on the Receptors, Transduction, Transmission, Processing, Perception, Recognition, Action
Term
Gustav Fechner founded ___ approach to perception
Definition
Psychophysical (use of quantitative methods to measure relationships between stimuli [physics] and perception [psycho])
Term
Any measurement of relationship between stimuli and perception (how different is color A from color B?)
Definition
psychophysics (Fechner)
Term
Study of how stimulus (pictures, mood) affects action and/or experience [of pain]
Definition
Psychophysics
Term
Measuring relationship between stimuli and physiological processes (____) and between physiological processes and perception (_____); how usually measured?
Definition
Physiological approach to perception; PH1, PH2; usually studied by measuring electrical responses in nervous system
Term
Measuring how neuron responds to different colors
Definition
PH1 (physiological approach)
Term
Measuring relationship between brain activity and person's perception of colors
Definition
PH2 (physiological approach)
Term
Approach to perception most often involving fMRI or electrodes
Definition
Physiological approach (PH1, PH2)
Term
Factors like knowledge, memories, and expectations we bring to situation that can influence our perceptions
Definition
Cognitive influences on perception
Term
Three main ways of measuring perception
Definition
Description (describe what we perceive), recognition (categorize and name stimulus), detection (Fechner; measure relationship between stimuli and perception)
Term
Smallest amount of stimulus energy needed to detect stimulus; _ _
Definition
Absolute threshold; RL (reiz limen, like subLIMINal message)
Term
Determine absolute threshold using three methods:
Definition
Method of limits, method of adjustment, method of constant stimuli
Term
Present stimuli in ascending/descending order of intensity and indicate responses as presented to observer
Definition
Method of limits
Term
In Method of Limits, change from yes to no (or vice versa)
Definition
Crossover point / threshold
Term
In Method of Limits, if observer said too many "yes"es they would have a ____ threshold
Definition
Lower
Term
Adjust stimulus intensity continuously until observer can just barely perceive/detect stimulus
Definition
Method of Adjustment
Term
How to measure threshold in Method of Adjustment
Definition
Average of adjustments
Term
Present 5-9 stimuli with different intensities in random order, repeated many times
Definition
Method of Constant Stimuli
Term
How to measure threshold of Method of Constant Stimuli
Definition
Intensity resulting in detection on 50% of trials
Term
Most accurate way to measure absolute threshold, but also the most time-consuming
Definition
Method of Constant Stimuli
Term
Potentially biased ways of measuring absolute threshold
Definition
Method of Limits and Method of Adjustment
Term
Smallest difference between two stimuli a person can detect; founder
Definition
Difference threshold (DL); Ernst Weber; "just-noticeable difference" (jnd)
Term
Actual amount that has to be added to one stimulus for subject to tell that there's a difference
Definition
DL (difference threshold)
Term
Weber's Law
Definition
Ratio of DL to standard stimulus (S) is constant; DL/S = K (K = constant, Weber's fraction); DL = K*S
Term
Weber fraction (K) remains about constant for particular sensory modality; more easily detect ____ than ____
Definition
More easily detect electric shocks and lifted weights than sound, light, or taste
Term
Relate perceived magnitude and stimulus intensity (assign S a value and then assign number to each stimulus of different intensity proportional to S)
Definition
Magnitude estimation
Term
As intensity increases, magnitude increases...but not as rapidly as intensity
Definition
Response compression
Term
As intensity increases, perceived magnitude increases even more rapidly; example
Definition
Response expansion; electric shocks
Term
Intensity of stimulus and our perception of magnitude follow same equation for each sense
Definition
Power functions; Stevens's Power Law: P = K*S^n where P = perceived intensity, K = constant, S = stimulus intensity, n = constant power
Term
Taking log of both sides of Stevens's Power Law equation turns function into ____; slopes indicate ____; slopes > 1 indicate _____
Definition
Straight line; n (exponent of power function); n > 1 = response expansion (like electric shock)
Term
Find one stimulus among many as quickly as possible
Definition
Visual search
Term
Time between presentation of stimulus and observer's response to stimulus
Definition
Reaction time
Term
Method to get rid of bias (like signal detection theory)
Definition
Two-interval forced-choice tracking
Term
Aristotle said ___ was seat of mind/soul; ___ said health/thoughts/emotions determined by spirits flowing from brain cavities called ventricles; ____ said pineal gland as seat of soul
Definition
heart; Galen; Rene Descartes
Term
1660s man responsible for mental functioning, localization according to brain regions
Definition
Thomas Willis
Term
Discovered staining (chemical technique), so possible to see entire neuron --> acceptance of neuron theory
Definition
Camillo Golgi
Term
"Father of Neuroscience" who drew retinas, cells
Definition
Santiago Ramón y Cajal
Term
1906 winners of Nobel prize for physiology and medicine
Definition
Cajal, Golgi
Term
Two opposing ideas of 1800s between Golgi and Cajal
Definition
reticular theory (nervous system = large network of fused nerve cells), neuron theory (nervous system = distinct elements/cells); Cajal used golgi stains to prove second
Term
mid-1800s proposed doctrine of specific nerve energies; explain
Definition
Johannes Mueller/Müller; our perceptions depend on "nerve energies" reaching brain; specific quality experienced depends on which nerves stimulated (optic nerve/seeing, auditory nerve/hearing)
Term
Activity by particular sensory nerve always conveys same kind of information to brain
Definition
Law of Specific Nerve Energies
Term
Person who recorded electrical signals from single sensory neurons in 1920s
Definition
Edgar Adrian
Term
2-mm-thick layer covering brain surface; contains machinery for creating perception and other functions like language, memory, thinking
Definition
Cerebral cortex
Term
Modular organization
Definition
Specific functions served by specific areas of cortex; localization
Term
Important for sensory transmission and processing (like sensory relay center); located toward the core
Definition
Thalamus
Term
Receives input from optic nerves (eyes) and sends back to cortical regions like visual cortex
Definition
Thalamus, "sensory relay center"--not just for vision, but for many senses
Term
Visible axons of neurons, where transmissions occur
Definition
White matter (fatty myelin sheaths)
Term
Purpose = respond to environmental stimuli and transduce them into electrical signals; also comunicate with others so signals can travel long distances
Definition
Neurons (transduction, transmission)
Term
Two glial cells that make up myelin sheath
Definition
Oligodendrocytes (can wrap around axon many many times) and Schwann cells (only wrap one time to make segment)
Term
Difference between oligodendrocytes and Schwann cells
Definition
Oigodendrocytes myelinate central nervous system (like DENDRiTES in brain); Schwann cells myelinate peripheral nervous system
Term
Neurons specialized to respond to environmental stimuli like pressure, light, air/liquid chemicals, etc.
Definition
Receptors; part of each receptor reacts to environmental stimuli and triggers generation of electrical signals, which are transmitted via axons to neurons
Term
Oscilloscope
Definition
Used to measure difference in charge between recording microelectrode and reference microelectrode in single neuron
Term
Difference of charge between inside and outside of neuron
Definition
Polarization
Term
Taking difference in charge farther from 0mv, so making difference larger
Definition
Hyperpolarization
Term
Taking difference in charge closer to 0mv, so making difference smaller
Definition
Depolarization
Term
Difference in charge when at resting potential
Definition
-70mv
Term
Action potential brings axon to what charge?
Definition
+40mv
Term
Function = communicate information via electrical message traveling along axon's length, carried by ions
Definition
Action potential
Term
Action potential impulse isn't like electrons through power cord because...
Definition
Regenerated at points all along the way
Term
Membrane channels whose permeability (whether open or closed) depends on voltage difference across membrane--what we're measuring with our two electrodes
Definition
Voltage-gated channels
Term
Procaine, Novocaine, cocaine, tetrodotoxin (pufferfish) block ____
Definition
Block voltage-gated sodium channels, so signals of pain can't reach brain
Term
Scorpion venom blocks ____
Definition
Voltage-gated potassium channels, so action potential goes up and never goes back down; increasing sodium inside cells leads to death
Term
During depolarization (working toward 0mv from -70mv), what does voltage sensor do?
Definition
Not as repelled by the outside of the cell, so opens little gateway so channel opens and Na+ can flow from outside to inside of cell (concentration AND electrical gradient)
Term
During return to negative polarization, how does neuron reach resting potential?
Definition
Voltage-gated potassium channels open, K+ ions flow out because of concentration gradient and (at peak of action potential) electrical gradient, taking positive charge with them (so --> negative)
Term
After resting potential, this restores original concentrations/distributions of ions; "resetting" concentrations
Definition
Sodium potassium pump
Term
Actually brings cell back to its resting potential
Definition
Voltage-gated potassium channel
Term
Action potentials "propagate", meaning:
Definition
traveling waves along length of entire axon
Term
Graded potential means ________, so as they go along they get weaker so there are regeneration places called _____
Definition
Passive diffusion; Nodes of Ranvier (make sure AP signals are just as strong at end of AP as it was in the beginning)
Term
Myelinated neurons increase ____, therefore saving ____ and ____
Definition
Increase speed, saving neurons and energy
Term
When you have enough depolarization to reach a certain threshold, like -50mv --> +30 or +40mv; "all or none law"
Definition
Threshold of excitation
Term
Creates and maintains the concentration gradient
Definition
Sodium potassium pump embedded in membrane; pull 3 Na+ ions OUT of cell and put K+ ions INTO cell
Term
Difference between protein channels and pumps
Definition
Pumps require energy to run because working against concentration gradient--don't help PASSIVE movement
Term
Membrane is highly permeable to one specific type of molecule but not to others
Definition
Selective permeability
Term
At rest, inside of membrane is slightly ___ with respect to outside
Definition
Negative (that's why -70mv at rest)
Term
At rest, what are gradients doing with regard to Na+ ions?
Definition
Concentration: OUT to IN; electrical: OUT to IN; so STRONG movement from OUT to IN
Term
At rest, what are the gradients doing with regard to K+ ions?
Definition
Concentration: IN to OUT; electrical: OUT to IN; so fairly balanced because opposing forces
Term
Once response is triggered, travels all the way down axon without decreasing in size (all or nothing)
Definition
Propagated response
Term
Interval between time one nerve impulse occurs and next can be generated in axon
Definition
Refractory period; short time after AP when neuron resists firing more APs; need stronger stimulation than normal to reach threshold of excitation and fire another AP
Term
Establishes baseline level of nerve firing because APs occurring in absence of environmental stimuli
Definition
Spontaneous activity
Term
Open up to send signals to vesicles when sense depolarization coming from presynaptic cell
Definition
Calcium channels
Term
Movement of neurotransmitters into synaptic cleft
Definition
Exocytosis
Term
Neurotransmitters activate ____ on the postsynaptic cell membrane
Definition
Ligand-gated channels (ion channels)
Term
Depolarization of postsynaptic cell
Definition
Excitatory post-synaptic potential (EPSP)
Term
Hyperpolarization of postsynaptic cell
Definition
Inhibitory post-synaptic potential (IPSP)
Term
More ____ (ion) leads to EPSP (excitatory)
Definition
Na+ (remember scorpion venom)
Term
Less ____ (ion) leads to hyperpolarization (inhibitory)
Definition
K+ (since losing +)
Term
More _____ (ion) leads to hyperpolarization (inhibitory)
Definition
Chloride (Cl- , so you're adding -)
Term
"Trigger zone" where the axon LEAVES the soma/cell body of the neuron; the first point that has voltage-gated sodium channels
Definition
Axon hillock
Term
"All or nothing" -- when reaching axon hillock, about to leave soma/cell body
Definition
Digital (as opposed to analog, which is graded and can range)
Term
What happens when NT makes contact with receptor site matching its shape?
Definition
Activates receptor site and triggers voltage change in receiving neuron
Term
Appearance of stimulation is _____ for transmission in circuits with NO convergence
Definition
Flat line
Term
Synapsing of 2+ neurons onto a single neuron
Definition
Convergence
Term
Area on receptors that influences neuron's firing rate
Definition
Receptive fields
Term
Where is receptive field for vision?
Definition
Area on retina; light hitting this area on retina causes change in firing rate in neuron we're recording from
Term
Areas of receptive field are arranged in center region that responds one way and a surround region that responds the opposite way
Definition
Center-surround receptive field
Term
Effect caused because center and surround of receptive field respond in opposite ways, so can cancel each other out
Definition
Center-surround antagonism
Term
Representations of particular environment objects by the firing of single neurons--tuned to respond specifically to that object
Definition
Specificity coding
Term
Example of specificity coding no longer accepted
Definition
Grandmother cells
Term
Neurons involved in specificity coding ("grandmother cells")
Definition
Hippocampus and medial temporal lobe, associated with memory storage
Term
Representation of particular object by pattern of firing in groups of neurons
Definition
Distributed coding
Term
In between specificity coding and distributed coding; distributed coding with just a few neurons (like Jennifer Aniston study)
Definition
Sparse coding
Term
Idea that particular object is represented by firing of relatively small number of neurons
Definition
Sparse coding
Term
Determining/finding connections between environmental stimuli and neural firing
Definition
Neural correlate of consciousness (NCC)
Term
"Easy" problem of consciousness
Definition
Finding NCC (neural correlate of consciousness), because possible to discover many connections between neural firing and experience
Term
"Hard" problem of consciousness
Definition
How do physiological responses become transformed into experience?
Term
Vision begins when what happens?
Definition
Visible light (band of energy within electromagnetic spectrum 400-700nm) is reflected from objects into eye
Term
Process of vision
Definition
Light reflected from environment objects enters eye through pupil, focused by cornea and lens to form sharp images on retina, which contains receptors for vision
Term
The types of visual receptors in retina
Definition
Rods and cones (named for appearance)
Term
Transparent/clear covering of front of eye; accounts for 80% of eye's focusing power BUT fixed in place so can't adjust focus
Definition
Cornea
Term
White part of eye
Definition
Sclera
Term
Clear; responsible for remaining 20% of eye's focusing power and CAN change shape to adjust focus to accomodate for stimuli at different distances
Definition
Lens
Term
____ is the clear covering in FRONT of the eye; ____ is also clear but is BEHIND the iris
Definition
Cornea; Lens
Term
All around side of lens in all directions; can contract and change curvature of lens to change focus
Definition
Ciliary muscle
Term
Fluid in front of lens = ___; fluid behind lens = ____
Definition
Aqueous humor (in front = A); vitreous humor (behind = V)
Term
At center of vision, provides us with acuity/detail
Definition
Fovea
Term
Creates natural blind spot about 18* outside direct front vision in each eye
Definition
Optic nerve head (where all are leaving the eye)
Term
Objects that are ____ need more bending to bring focus point on retina, like adjusting zoom on camera to adjust for object's distance
Definition
Near
Term
When you change focus (like something close to eye), you're changing ____
Definition
Accommodation
Term
Distance at which lens can no longer adjust to bring close objects into focus; when you feel a "strain" in your eye
Definition
Near point
Term
"Old eye"; distance of near point increases as person gets older, so near point gets farther and farther away
Definition
Presbyopia; loss of ability to accommodate because lens hardens with age and ciliary muscles become weaker, so less focusing power
Term
For presbyopia, point is going ____ retina
Definition
behind
Term
Nearsightedness; can see nearby objects clearly; point is ____ retina
Definition
Myopia; in front of retina
Term
Two causes for myopia
Definition
Cornea and/or lens bends light too much, or eyeball is too long
Term
Distance at which spot of light becomes focused on retina
Definition
Far point
Term
Farsightedness; can see distant objects clearly; cause
Definition
Hyperopia; short eyeball, so not enough bending of light...difficult to accommodate to close objects
Term
Lack of radial symmetry in cornea or lens, so more like football instead of basketball; things are blurred in one direction/radius (often at young ages but grow out of it)
Definition
Astigmatism
Term
Lens clouds over; way to remove it
Definition
Cataract; phacoemulsification
Term
Reflects light into the eye with half-silvered mirror to see inside of eye; inventor
Definition
Ophthalmoscope; Hermann von Helmholtz
Term
Retina seen through ophthalmoscope
Definition
Fundus
Term
Light from optic nerve fibers hit ___ cells, then move to middle layer with __, __, and __ cells, then into ___ cells
Definition
Ganglion; middle layer (amacrine, bipolar, horizontal cells); receptor cells (photoreceptors = rods and cones)
Term
What carry out transduction?
Definition
Visual receptors: rods and cones
Term
___ : color vision :: ___ : acuity (but color blind)
Definition
cones = color, rods = acuity but color blind
Term
Why are rods more sensitive to light than cones?
Definition
They have convergence (whereas cones in fovea do NOT...although cones on periphery sort of do)
Term
Rod outer segments are where what happens, and how?
Definition
Where light creates electricity; on stacks of discs are visual pigment molecules with long strands of proteins called opsin
Term
Retinal + opsin; sensitive to light
Definition
Rhodopsin (on rod outer segments)
Term
Process of transduction, beginning with retinal
Definition
Light-sensitive retinal absorbs one photon of light, causing rhodopsin to change shape--retinal breaks away to signal light's presence
Term
When retinal changes shape after triggered by photon
Definition
Isomerization
Term
Who found that RL for detecting light was 100 photons? Of those, how many absorbed by light-sensitive retinal part of visual pigment?
Definition
Hecht (1940s, psychophysical experiment); 50 bounce off cornea or absorbed by lens and vitreous humor, and only 7 absorbed while 43 hit larger opsin (NOT sensitive to light)
Term
Is retinal or opsin = sensitive to light?
Definition
Retinal
Term
Rods' response to light; when are sodium channels kept open, and when do they close?
Definition
Open in the dark because rhodopsin inactive; but in the light, rhodopsin = bleached so sodium channels close
Term
Glutamate ____ the cell it signals to (regarding rods' response to light)
Definition
inhibits
Term
Three types of cones, each with different type of opsin molecule
Definition
Short, medium, or long wavelength cones...whereas rods are right in the middle of the wavelength at 500nm
Term
Sequence of reactions triggered by activated visual pigment molecule
Definition
Enzyme cascade (since enzymes facilitate chemical reactions)
Term
In the fovea there are only _____; in periphery, mostly ______; in blind spot, there are _____
Definition
fovea = cones, periphery = mostly rods; blind spot = no receptors
Term
Most common in elderly; destroys cone-rich fovea and small area surrounding it, creating blind spot in central vision if looking at something directly
Definition
Macular degeneration
Term
Retina degeneration passed genetically; poor peripheral vision
Definition
Retinis pigmentosa
Term
Sensitivity found by adjusting light intensity so that can just barely be seen
Definition
Light-adapted sensitivity (since measured while eyes adapted to light)
Term
How do rod and cone dark adaptation differ?
Definition
Rods = very slow and gradual increase in sensitivity over ~30 min; cones = very rapid increase and then levels out at 2 min
Term
Born without rods, so poor acuity and no color vision
Definition
Rod monochromats
Term
Place where rods begin to determine dark adaptation curve
Definition
Rod-cone break (5-7 min)
Term
Curves of detection threshold graph (dark adaptation) are determined by what?
Definition
Regeneration of rhodopsin
Term
Retinal and opsin become rejoined after being split apart / bleached
Definition
Visual pigment regeneration
Term
Condition in which visual pigment can't regeneration; cause
Definition
Detached retina; traumatic injuries of eye/head--so when visual pigments bleached and retinal and opsin separated, can't be recombined; become blind
Term
Observer's sensitivity to light at each wavelength across visible spectrum
Definition
Spectral sensitivity
Term
Less light is needed to see wavelengths ...where?
Definition
In middle of spectrum compared to at either extreme
Term
Rods are more sensitive to ____-wavelength light than cones
Definition
short (blue, purple, green) -- remember the Purkinje effect/shift
Term
Why greens/blues/purple (short wavelengths) look more intense in semi-darkness
Definition
Purkinje effect/shift
Term
Why can we read things like fine print so accurately with our foveas?
Definition
In fovea, each cone receptor has its own bipolar and its own ganglion cell--a "direct line"; also, receptive fields are much smaller so easy to tell to tiny degree where light is stimulating those receptive fields separately
Term
Reflective shield that means "bright carpet" why nocturnal animals have greater sensitivity in dim light
Definition
Tapetum lucidum (lucid tapestry?)
Term
Rods' convergence ____ their ability to resolve details (acuity)
Definition
decreases
Term
Inhibition transmitted across retina; studied in what creature?
Definition
Lateral inhibition; horseshoe crab (Limulus)
Term
Illusion: See spots at intersections
Definition
Hermann gride
Term
Why do white spaces between intersections of Hermann grid seem a bit brighter (76 instead of 60)?
Definition
Black square areas send almost NO lateral inhibition because not stimulated by light; however, surrounding white areas send lateral inhibition
Term
As stimulation increases, inhibition ____
Definition
increases
Term
Illusory light and dark bands near a light-dark border
Definition
Mach bands
Term
Lateral inhibition can't explain what illusion? Possible explanation?
Definition
White's illusion; belongingness (area's appearance is influenced by part of surroundings to which area appears to belong--lefthand rectangle looks to be behind bars, righthand appears to be in front of bars)
Term
Eye --> optic nerve --> ______ in the thalamus
Definition
Lateral Geniculate Nucleus (LGN)
Term
From LGN, signals travel to ____ (primary visual receiving area)
Definition
Striate cortex; striped/striated by nerve fibers
Term
Primary (first to receive visual input) visual cortex is located where?
Definition
Very back tip of brain
Term
Controls eye movements and other visual behaviors; receives ~10% of fibers from optic nerve
Definition
Superior colliculus
Term
Visual input from the LEFT visual field of EACH retina is processed where?
Definition
Crosses over at optic chiasm and is processed by RIGHT side of brain
Term
Half of retina closer to nose = ____; half away from nose = ____
Definition
Nasal; temporal
Term
"Geniculate" means "little knee"--why?
Definition
LGN look like little bent knees
Term
LGN neurons have ____ configuration, similar to ____ cells
Definition
center-surround, like retinal ganglion cells
Term
Major function of LGN
Definition
Regulate neural information as it flows from retina to visual cortex; weed out some information when necessary
Term
10% optic nerve fibers arrive at superior colliculus; where do other 90% go?
Definition
LGN
Term
Tons of axons radiating from LGN to cortex, actually visible in cross-sections
Definition
Optic radiations
Term
Layers of LGN alternate in what way?
Definition
Between receiving signals from the ipsilateral (same side) eye and contralateral (opposite side) eye
Term
Map in which each point on LGN corresponds to point on retina (diagonally opposite)
Definition
Retinotopic map [on LGN]
Term
More than ____% of cortex responds to visual stimuli; we know this because of who?
Definition
80%; Hubel and Wiesel experiments with flashes of light on retina
Term
Hubel and Wiesel discovered that cells in striate cortex have ___ excitatory and inhibitory areas/regions, arranged in what way (and called what)?
Definition
have FIXED excitatory/inhibitory areas, arranged side by side instead of center-surround, called "simple cortical cells"
Term
Simple cortical cell's orientation tuning curve (showing impulse/excitation) depends on what?
Definition
Degree of tilt of a stimulus
Term
Complex cells
Definition
Cortical cells that don't respond just to orientation of lines but instead to moving bars--must be correctly oriented moving across entire receptive field, particularly in certain movement direction
Term
Unlike simple cells, the excitatory zone of complex cells is NOT ____
Definition
fixed
Term
If you mapped out excitatory area of a simple cell it would look like _____; of a complex cell it would look like _____
Definition
a line; a box
Term
Fire to moving lines of a specific LENGTH or to moving corners or angles; have very strong inhibitory regions
Definition
end-stopped cells, or hypercomplex cells
Term
Feature detectors
Definition
Simple, complex, and end-stopped cells, since they fire in response to specific FEATURES of the stimulus (orientation, direction of movement, etc.)
Term
As travel farther from retina, neurons fire to ______ stimuli
Definition
More complex
Term
If neurons fire for long enough, become fatigued...adapt; causes what?
Definition
Selective adaptation; neuron's firing rate decreases and neuron fires less when that stimulus is immediately presented again
Term
Grating stimuli
Definition
Alternating bars, sometimes with different orientations or contrasts
Term
Difference in intensity at which bars can just barely be seen
Definition
Contrast threshold
Term
If animal reared in environment with only certain types of stimuli neurons responding to these stimuli will become more prevalent; idea follows from neural plasticity or experience-dependent plasticity
Definition
Selective rearing
Term
Response properties of neurons can be shaped by perceptual experience
Definition
Selective rearing (neural plasticity, experience-dependent plasticity)
Term
If you were surrounded by vertical lines all your life, neurons respond predominantly to ___
Definition
verticals
Term
If you sew up cat's eye at birth for 2-3 months, even 3 years later neurons in cortex respond almost solely to the eye never sewed shut
Definition
Ocular deprivation
Term
Brain ignores input from one eye; causes
Definition
Amblyopia (form of ocular deprivation); strabismus (lazy eye, cross-eye), congenital cataracts, anisometropia (different refractive powers in two eyes)
Term
Neurons near each other in the cortex have receptive fields _____ on the retina; this helps with ____
Definition
near each other; increased efficiency
Term
8-10% of retinotopic map of cortex = area representing cone-rich fovea, whereas fovea's size is only 0.01% of retina's area
Definition
Cortical magnification factor
Term
Distorts image on fovea to make visual field representation very large
Definition
Cortical magnification factor
Term
Perpendicular to striate cortex's surface, so all neurons within have receptive fields at same location on retina
Definition
Location columns
Term
Each contains cells responding best to a particular orientation; adjacent ones have cells with ____ preferred orientations
Definition
Orientation columns (in striate cortex); slightly different preferred orientations
Term
Preferential response to one eye compared to other, so each neuron encountered along perpendicular electrode track responds best to same eye
Definition
Ocular dominance columns (in striate cortex)
Term
About 80% of neurons in V1 (primary visual cortex) respond to input from _____, but most cells respond best to ______
Definition
both eyes; one eye
Term
In ocular dominance columns, the ________ changes as you go across various columns in a certain direction, usually ___ ___ ___ ___
Definition
preferred eye; left right left right
Term
Larger unit with combination of ____, ____, and ____ columns
Definition
Hypercolumns; location, orientation, ocular dominance
Term
Hypothetical drawing of hypercolumns from Hubel and Wiesel; why incorrect?
Definition
Ice-cube model; not that simple--in some places orientation columns aren't side by side but instead arranged like pinwheels
Term
The striate cortex breaks everything down, but beyond V1 the brain ______
Definition
builds up the visual process again, so we can recognize and interact
Term
Object discrimination problem
Definition
Monkey (with ablasion) shown one object and then presented with two-choice task including target object and another stimulus; gets food for pushing target object
Term
Landmark discrimination problem
Definition
(Monkey with ablasion) food hidden closest to certain "landmark" stimulus
Term
Pathway from striate cortex to temporal lobe = _____ or ____; located where?
Definition
"what pathway" or "ventral pathway"; located along lower surface/side of temporal lobe (what lower ventana toward the ground?)
Term
Pathway from striate cortex to parietal lobe = ____ or ____; location
Definition
"where pathway" or "dorsal pathway"; back/upper surface of organism, so top of brain (where is the door UP to heaven?)
Term
Dorsal stream isn't just "where" but also ___; should be changed to "____"
Definition
taking action (location + movement, not just location); should be "how" to direct action with regard to stimulus (HOW do I get UP to the door?)
Term
Study of behavioral effects of brain damage in humans
Definition
Neuropsychology
Term
Situations in which one function is absent while another is present; two types
Definition
Dissociations; single (in one person), double (2+ people in opposite situations)
Term
Patient DF had ___ damage and could not _____, but COULD _____ because involved ____
Definition
ventral pathway damage and couldn't match orientation (perception/ventral/what), but could easily "mail" (action/dorsal)
Term
Inability to recognize objects visually
Definition
Visual agnosia
Term
Two small lines inside tilted squares appear slightly tilted in opposite directions even though parallel; used to study what?
Definition
Rod and frame illusion; used to study difference between matching and grasping, or what (ventral) and how (dorsal)
Term
Structure that's specialized to process information about particular type of stimulus
Definition
Module
Term
Three examples of modules; location
Definition
FFA (fusiform face area), EBA (extrastriate body area), PPA (parahippocampal place area); temporal cortex
Term
Location of FFA
Definition
Fusiform face area = inferior (underside of) temporal cortex
Term
Neural selectivity...shaped by ___ or ___?
Definition
Evolution or experience?
Term
Greeble recognition and experience-dependent plasticity are examples of what?
Definition
How neurons (neural selectivity) can be shaped by experience, not evolution
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