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148 Cards in this Set

  • Front
  • Back

What are the methods for studying visual perception

*Behavioral methods


*Physiological methods


*Computational methods

What are behavioral methods for studying visual perception?

*Phenomenology (description)




*Demonstration




*Psychophysics




*Analysis of visual motor behavior

What are the components of psychophysics?

*Magnitude of estimation




*Method of adjustment




*Method of constant stimuli

What is phenomenology

Describe what you see




(When make an observation, then want to pursue further if don't understand)

What is demonstration

May set up structured experiment of visual display and see what they see to know if broad phenomenon

What are analysis of visual-motor behavior

Behavioral methods get own assessments by making adjustments

What are physiological methods for studying visual perception?

*Anatomical studies of neural "wiring"




*Clinical case studies [Weakness, every instance is uncontrolled and unique]




*Experimental modifications (non-humans)




*Non invasive imaging (EEG, fMRI, etc) [Electrode; braod news but doesn't go down t individual neurons]




*Invasive recording (non humans) [Precise information but only look at a small sample]




*Tradeoffs [Each of these techniques have their own strengths and weaknesses]




*The Global Brain Initiative [Spend 10 billion dollars to decrease these tradeoffs and have complete map of what the brain is doing]

What are computational methods for studying visual perception

*Computational modeling




*Computer vision




*Robotics (vision in action)

What is the definition of visual perception

Visual perception is the activity by which an organism uses its eyes to obtain information about its environment and about itself in relation to its enviornment




Visual perception is the activity by which an organism uses its eyes to obtain information about its environment and about itself in relation to its environment

What is figure/ground segregation

Sort things out to separate objects from field 

Sort it out form background 

Sort things out to separate objects from field




Sort it out form background

What is object recognition

Identify and look at it and recognize the object

Identify and look at it and recognize the object

What is generalization and specificity

Generalize a lot of different image as object




But also specific




Wants to generalize all chairs but also don't want to mix up with tables so have to be specific

What are parts of what things are?

*Figure/Ground Segregation


*Object Recognition


*Generalization/Specificity

What are properties of things?

*Size, shape, color, orientation


*Material properties



Is familiarity of thing important for knowing the property of things?

No

What are properties of animate things?

Perception of expression (for example)

What are components for knowing where things are?

*Space perception (spatial layout)


*Absolute (metric) egocentric distance


*Absolute exocentric distance


*Relative (ratio) exocentric distance

What is space perception (spatial layout)?

Get information based on where they are. See their spatial relation to each other

What is the absolute (metric) egocentric distance

Distance from person to object

Distance from person to object

What is absolute exocentric distance

Distance between two objects 

IE distance between these two chairs is ~10 ft

Distance between two objects




IE distance between these two chairs is ~10 ft

What is relative (ratio) exocentric distance

This chair is closer to the table. Can express distance in ratio

This chair is closer to the table. Can express distance in ratio

What does locating myself in the enviornment

Where I (the observer) am

How do you locatate where I (the obser) am?

*Locating myself in the environment


*Task-specific spatial information


*Visual feedback to help guide visual-motor activities

What behaviors the environment affords

Can see object can be picked up and where cna grasp it




See specifically how want to perform that grasp

How does light convey information about the environment

The optic array




(Light coming to eye has structure and is structured by the environment's surface to a potential point of observation)

What is radiation from a luminous source like

Source of illumination, illminates the environment and differentially (depending on shadow and surfaces)

What happens after radiation from illumination source

Scatter reflection of light from from surfaces

What is light scatter like between matte surfaces and partially polished surfaced

More or less scattered based on if look at matte surfaces versus polished surfaces

These are qualities that will tell us about material quality 

More or less scattered based on if look at matte surfaces versus polished surfaces




These are qualities that will tell us about material quality

What is this showing

What is this showing

Boundaries in optic array




These reflected rays are essentially creating boundaries in optic array epends on surfaces light is reflected from and different affect light reflected off

How does the effective array and the observer work with each other

At any point of enviornment can place array. Eye picking up a sample but not picking up all 360 degrees at once




Movement transforms the optic array. When observer may around think of them moving from one array to another and look at transformations that occur as move from 1 array to another (get different environment based on structure of light)

How does optical change with movmeent

Optical transition from one vita to another 

Optical transition from one vita to another

Does the environment have a structure

Yes, a spatial layout of surfaces

The optic array has a structure that is produced by what

The structure of the environment

The structure of the optic array carries information about what

The structure of the environment

What are projective ambiguity

*Ambiguity of size/distance

*Ambiguity of slant/shape

*Ambiguity of size/distance




*Ambiguity of slant/shape

What reduce ambiguity

Environmental constraints

In order for optic array structure to uniquely specify enviornmental structure what has to happen

Some additional constraints on the enviornment are usually necessary

For a particular organism, is every possible environment equally likely

No

What are environmental constraints like

Some are very general other are more specific




Many constraints are contingent or statistical

Does every organism have the same or own ecological niche

Has its own ecological niche

What was the ground support of hominins act as

Environmental support

Does the distance along the ground increase or decrease as angular elevation in the optic array increases

Increase

Increase

Convex and concave surfaces produce what in the image

Gradients of shading

What is the gradient of light of concave/convex light from up and above



Gradient of shading depends on what

Shape and direction of illumination

An illuminated curved surface produces what

A gradient of shading (light to dark) in the image

The direction of the light gradient depends on what

Both the direction of curvature (convex or concave) and the direction of illumination (then above or below)

What is the environmental constraint for illumination

The direction of illumination tends to be from above (IE sunlight)

When a cuneiform is lit from below instead of above what does that look?

Is perceptually reversed and looks like wedges

Violating constratints can produce what

Visual illusion

Is the normal human visual system only the eyes and brain

No, contains striate cortex/extrastriate cortex, environment, EOM

How do you get visual information when greater than 20 degrees retinal eccentricity

Turning the eyes and the head

The gaze is the sum of the eye and head have to coordinate to get onto the target

VOR from inner ear`

Turning the eyes and the head




The gaze is the sum of the eye and head have to coordinate to get onto the target




VOR from inner ear`

Can we get visual information from manipulating an object

Yes

What is important of eye-hand coordination

Important coordination

Eye-hand coordinate system for each coordinate of arms 

Important coordination




Eye-hand coordinate system for each coordinate of arms

Can you get visual information by staying still

No, has to be moving around 

There is also interaction of the body, head and eyes during walking 

No, has to be moving around




There is also interaction of the body, head and eyes during walking

What are perceptual action

*Eye movement


*Head movements


*Manipulative movements


*Body movements

What is the perception-action cycle

Have information coming through optic array

Have information coming through optic array

Is visual perception only an activity of the eyes and brain

No, is an activity of the whole organism

The overall process of visual perception can best be described as:




a) A retinal mechiansm


b) An activity of an organism


C) A universal process that works equally well in any environment


D) A process that relies on the same environmental constraints in every organism

B) An activity of an organism

What is the pathway of the geniculostriate pathway?

Retina --> Lateral geniculate Nucleus (LGN) --> Striate Cortex (V1)

What does foveal vision help us do?

*High central acuity




*Frontal eyes leads to wider binocualr fields which helps with stereopsis




*Excellent close up depth perception




*Precise visual-motor control

What is this? Explain 

What is this? Explain

Flattened rabbit retina




Instead of a fovea the rabbit has a streak out towards the horizon and helps the rabbit look into the distance.




This is the ganglion cell isodensity contour map (the point is to show how many ganglion cells there are in the rabbit's ganglion)




the area around the rabbits center ring is the highest ganglion cell density

Does the rabbit have horizontally or vertically distributed acuity?

Horizontally

Where are the rabbit's eyes placed

Lateral

What type of binocular overlap does the rabbit have? Small or large?

Small

Does the rabbit have a wide or narrow monocualr field of view

Wide

Does the rabbit have a good or bad view of predators

Good

Does retina have back and forth communication or is it just one way?

One way

The output of the ganglion cells is what type of system?

Center surround

What are the two types of center surround

On center


Off center

What is the concentration of different cells like as you move from photoreceptors down LGN to V1 neurons etc

Funnel down because then won't overcompress optic nerve with too much neurons. However, if funnel down throwing away information what wants to do is compress informatio n and encode to preserve as much useful information as possible. The center s...

Funnel down because then won't overcompress optic nerve with too much neurons. However, if funnel down throwing away information what wants to do is compress informatio n and encode to preserve as much useful information as possible. The center surorund system is the way to do that




Then there is a big expansion of information into v1

What is the functional significance of center-surround organization

*Compression (~100:1) from retinal receptors to ganglion cell outputs




*Uniform areas of the image are uninformative




*Areas with change (spatial and/or temporal) are informative




*Center-surround organization selectively responds to informative parts of the image

Which have smaller dendritic fields between off retinal ganglion cells and on ganglion cells

Off retinal ganglion cells

Are off retinal or on ganglion cells more numerous

Off cell are more numerous



Are off cell or on cells have denser dendritic field

Off cells (and have more synapses per unit of visual field area)

Natural images contain more positive or negative contrasts at every scale

Negative

The desity of synapses within a dendritic field is matched to what

The information content of the field

What time of cells are found in the cortical area V1 (striate cortex)

Simple cells

What do simple cells like

Likes edges or elongated objects but specfici orientation

What is tuning in reference to simple cells

Can make tuning curve based on how fast drops off as move to a different orientation

What is a narrowly tuned for simple cells

Only respond to small changes (drops off quickly)

What does broadly tuned mean for simple cells

Only respond to wide expanse of orientations (Drops off slowly)

Is this lower or higher SF

Is this lower or higher SF

Lower

Is this lower or higher SF?

Is this lower or higher SF?

Higher

Visual system in straite extract from these edge orientation/frequency




Also look at how much information from L/R eye




As move horizontally changes gradually.




This is 1 mm(and complete representation) has a complete set of different balance of 2 eyes




This is hypercolumn (little area of cortex does complete local analysis for patch of visual image)

What are some image features that can be extracted by the geniculostriate pathway?

*Visual field location


*Contour orientation


*Spatial frequency (size) & phase


*Contrast/contrast polarity


*Ocular dominance/binocular disparity


*Spectral composition (color)


*Temporal frequency and motion velocity


*Direction of motion

What are the ecological constraints on V1 processing

Are the properties of V1 receptive fields matched to the statistical regularities of the organism's environment?




Statistical analysis of images from the natural environment can be used to generate artificial "optimal" receptive fields




These optimal RFs can then be compared to the properties of actual RFs in V1




Such analyses show that RF properties are often well adapted to the environment

Spatial frequency bandwidth




Narrow bandwidth (very selective)


Broad bandwidth (Narrow selective)




Dark dots = theoretical is the optimal distribution


Histogram is what actually find




Find relatively nice match between theoretical and actual

What is this? 

What is this?

Can do same thing with orientation

What is this? 

What is this?

This is length of receptive field

What is this?

What is this?

this is something adaptive persumably through evolution

For geniculostriate processing, the retinal image is analyzed into what

Multiple components relevant to the organism

For geniculostriate processing is the analysis local or not

Local





what does the geniculostriate processing having its analysis being local mean

Each hypercolumn analyzes one portion of the visual field




(It is more detailed in central than in peripheral vision)

Can RF properties be adapted to the statistical regularities of an organism's enviornment?

It may

What receive local analysis of geniculostriate processing

Higher cortical areas

Is cortex bigger in humans or in other animals

Bigger in humans




(It is more folded in humans)

What is this? 

What is this?

Wiring diagram of mutliple cortical visual areas




Cortical processing is a back and forth process except for the retina which is a one way street




(As go up from bottom to top also shows that there is higher levels of processing)

Is there specialized functions for each area of the cortex?

Yes

What is MT specialized for?

Motion




(90% motion selective, 0% color selective)

What can an issue with MT lead to?

Akinetopsia

What is akinetopsia

Motion blindness

What is V4 specialized for

Colro and form




(5% motion selective, 60% color selective)

What does damage to V4 lead to

*Achromatopsia


*Hemichromatosia

What is achromatopsia

No color viison

What is hemiachromatosia

Color vision only on half of the VF

Explain the demonstration that had the black and white stripes and red/green stripes spinning

The Black/white had different luminence


The red/green stripes was isoluminent




Will rotate both at same speed, stripes always parallel travel at same speed. Red green looks like it doesn't move but can compare them and see they are the same. There are costs to this, sometimes information being lost

What are the different pathways/streams from the occipital lobe?

Dorsal/Ventral Pathway

Dorsal/Ventral Pathway

What is the parietal stream?

Where/How




(More with spatial perception/layout)

What is the ventral stream?

What




(For object recognition)

What are the evidence of functional differences between dorsal and ventral streams?

*Experimental evidence (monkeys)


-Object vs landmark discrimination tasks




*Clinical case studies (Human neurology)


-Perception vs action

During experimental evidence, if a monkey brain has the temporal lobe removed what happens?

Has problem with object discrimmination

(In the example had two holes, one hole with food with covers. Has a specific cover that has food under that and monkey learns to do that. For the test to work) 

Has problem with object discrimmination




(In the example had two holes, one hole with food with covers. Has a specific cover that has food under that and monkey learns to do that. For the test to work)

During experimental evidence, if a monkey brain has the parietal lobe removed what happens?

(Tested with similar task, has two of the same covers over each hole but has a landmark (IE cylinder) placed adjacent to a well of food)

Has to do with landmark discrimination task
(Spatial localization)

(Tested with similar task, has two of the same covers over each hole but has a landmark (IE cylinder) placed adjacent to a well of food)




Has to do with landmark discrimination task


(Spatial localization)

Removal of the parietal lobe tissue results in problems iwth what

Landmark discrimination task

Removal of temporal lobe tissue resulted in problems with what

Object discrimination task

How did they test the dorsal and ventral pathways neurological evidence

*Behavior of patient DF


*Other patients show opposite effects

What did the behavior of patient DF show us?

*Damage to ventral pathway due to carbon monoxide poisoning

*Not able to match orientation of card with slot

*But was able to match orientation if she was placing card in a slot 

[In picture, left is the patient, right is normal patient]

*Damage to ventral pathway due to carbon monoxide poisoning




*Not able to match orientation of card with slot




*But was able to match orientation if she was placing card in a slot




[In picture, left is the patient, right is normal patient]

What does evidence show betwene ventral and dorsal pathways

Evidence shows double dissociation

What is the connection between action guidance and object recognition?

Velocity goes into both action guidance/object recogniton but different things done within different pathways

Velocity goes into both action guidance/object recogniton but different things done within different pathways

Higher areas synthesize in many or not many different ways the output of the V1 analysis to obtain information that is useful to the organism

Many




(Done by many, completely interacting, specialized visual cortical areas)

The dorsal stream is broadly specialized for what

Action guidance

The ventral stream is broadly specialized for what

Object perception and recognition

Are dorsal and ventral stream interconnected or not

Interconnected

What is the visual hemifields like

Crossover of 1 side of body to others

Crossover of 1 side of body to others

What are the crossover points in the brain like

Crossover points from one side of the body to the other

Crossover points from one side of the body to the other

What is the corpus callosotomy

Split-brain procedure

What gave us evidence for hemispheric specialization

*Clinical neurological observations


*Research with split-brain patients


*Research with normal subjects (accuracy, RT)


*Specialization varies with handedness

How many % of people are right handed

90%

Is hemispheric specialization different for left handed people

For some (but not all)

What is left hemisphere specialization like?

*Specialization for language


*Language production


*Language comprehension



Is there language comprehension in the right hemisphere?

Limited language comprehension in the right hemisphere: concrete words and simple sentences

What is Broca's area for?

Lanugage production 

Lanugage production

What is Wernicke's area for?

Language comprehension

Language comprehension

Is there anatomical hemispheric asymmetries?



Is planum temporale (Wernicke's area) larger in left or right hemisphere?

Left

Are right and left hemispheres of equal or unequal importance

Equal

What is right hemisphere specialization

Right hemisphere specialization for some nonverbal and spatial abilities

Can lateralization affect some clinical disorders

Yes

What does it look like when a patient draws a cube before and after a split-brain operation?

1) Left hand pre-op

2) Right hand pre-op

3) Left hand post-op

4) Right hand post-op

[Draw with left hand has the right hemisphere seeing the object (spatial recognition) and right hand seen by left brain (not spatial)]

1) Left hand pre-op




2) Right hand pre-op




3) Left hand post-op




4) Right hand post-op




[Draw with left hand has the right hemisphere seeing the object (spatial recognition) and right hand seen by left brain (not spatial)]

What is the Block design task

Arrange the blocks to match the design

Performance is timed for each hand 

Arrange the blocks to match the design




Performance is timed for each hand

What are the results from the block design task in a split brain patient?



What is pattern matching?

*Briefly present visual patterns




*Fixation selects hemisphere




*Point to matching pattern




*Hand selects hemisphere



Is there is a hemisphere that is better in pattern matching or equally good

Both hemisphere are equally good

What is left-hemisphere processing for?

*More piecemeal




*Analytic




*Special emphasis on temporal relationships

What is Right hemisphere processing for

*More global




*Holistic




*Special emphasis on spatial relationships

Do the two hemispheres normally cooperate in processing information?

Yes

What is the coordinate processing system of the two hemispheres run through

Corpus callosum

The sharing processing between hemispheres often leads to what

Better performance than if one hemisphere must perform the task alone