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148 Cards in this Set
- Front
- Back
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What are the methods for studying visual perception |
*Behavioral methods *Physiological methods *Computational methods |
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What are behavioral methods for studying visual perception? |
*Phenomenology (description) *Demonstration *Psychophysics *Analysis of visual motor behavior |
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What are the components of psychophysics? |
*Magnitude of estimation *Method of adjustment *Method of constant stimuli |
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What is phenomenology |
Describe what you see (When make an observation, then want to pursue further if don't understand) |
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What is demonstration |
May set up structured experiment of visual display and see what they see to know if broad phenomenon
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What are analysis of visual-motor behavior |
Behavioral methods get own assessments by making adjustments |
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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] |
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What are computational methods for studying visual perception |
*Computational modeling *Computer vision *Robotics (vision in action) |
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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 |
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What is figure/ground segregation |
Sort things out to separate objects from field Sort it out form background |
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What is object recognition |
Identify and look at it and recognize the object |
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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 |
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What are parts of what things are? |
*Figure/Ground Segregation *Object Recognition *Generalization/Specificity |
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What are properties of things? |
*Size, shape, color, orientation *Material properties |
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Is familiarity of thing important for knowing the property of things? |
No |
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What are properties of animate things? |
Perception of expression (for example) |
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What are components for knowing where things are? |
*Space perception (spatial layout) *Absolute (metric) egocentric distance *Absolute exocentric distance *Relative (ratio) exocentric distance |
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What is space perception (spatial layout)? |
Get information based on where they are. See their spatial relation to each other |
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What is the absolute (metric) egocentric distance |
Distance from person to object |
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What is absolute exocentric distance |
Distance between two objects IE distance between these two chairs is ~10 ft |
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What is relative (ratio) exocentric distance |
This chair is closer to the table. Can express distance in ratio |
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What does locating myself in the enviornment |
Where I (the observer) am |
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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 |
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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 |
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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) |
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What is radiation from a luminous source like |
Source of illumination, illminates the environment and differentially (depending on shadow and surfaces) |
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What happens after radiation from illumination source |
Scatter reflection of light from from surfaces |
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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 |
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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 |
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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) |
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How does optical change with movmeent |
Optical transition from one vita to another |
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Does the environment have a structure |
Yes, a spatial layout of surfaces |
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The optic array has a structure that is produced by what |
The structure of the environment |
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The structure of the optic array carries information about what |
The structure of the environment |
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What are projective ambiguity |
*Ambiguity of size/distance *Ambiguity of slant/shape |
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What reduce ambiguity |
Environmental constraints |
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In order for optic array structure to uniquely specify enviornmental structure what has to happen |
Some additional constraints on the enviornment are usually necessary |
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For a particular organism, is every possible environment equally likely |
No |
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What are environmental constraints like |
Some are very general other are more specific Many constraints are contingent or statistical |
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Does every organism have the same or own ecological niche |
Has its own ecological niche |
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What was the ground support of hominins act as |
Environmental support |
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Does the distance along the ground increase or decrease as angular elevation in the optic array increases |
Increase |
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Convex and concave surfaces produce what in the image |
Gradients of shading |
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What is the gradient of light of concave/convex light from up and above |
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Gradient of shading depends on what |
Shape and direction of illumination |
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An illuminated curved surface produces what |
A gradient of shading (light to dark) in the image |
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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) |
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What is the environmental constraint for illumination |
The direction of illumination tends to be from above (IE sunlight) |
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When a cuneiform is lit from below instead of above what does that look? |
Is perceptually reversed and looks like wedges |
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Violating constratints can produce what |
Visual illusion |
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Is the normal human visual system only the eyes and brain |
No, contains striate cortex/extrastriate cortex, environment, EOM |
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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` |
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Can we get visual information from manipulating an object |
Yes |
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What is important of eye-hand coordination |
Important coordination Eye-hand coordinate system for each coordinate of arms |
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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 |
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What are perceptual action |
*Eye movement *Head movements *Manipulative movements *Body movements |
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What is the perception-action cycle |
Have information coming through optic array |
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Is visual perception only an activity of the eyes and brain |
No, is an activity of the whole organism |
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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 |
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What is the pathway of the geniculostriate pathway? |
Retina --> Lateral geniculate Nucleus (LGN) --> Striate Cortex (V1) |
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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 |
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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 |
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Does the rabbit have horizontally or vertically distributed acuity? |
Horizontally |
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Where are the rabbit's eyes placed |
Lateral |
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What type of binocular overlap does the rabbit have? Small or large? |
Small |
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Does the rabbit have a wide or narrow monocualr field of view |
Wide |
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Does the rabbit have a good or bad view of predators |
Good |
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Does retina have back and forth communication or is it just one way? |
One way |
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The output of the ganglion cells is what type of system? |
Center surround |
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What are the two types of center surround |
On center Off center |
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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 surorund system is the way to do that Then there is a big expansion of information into v1 |
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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 |
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Which have smaller dendritic fields between off retinal ganglion cells and on ganglion cells |
Off retinal ganglion cells |
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Are off retinal or on ganglion cells more numerous |
Off cell are more numerous |
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Are off cell or on cells have denser dendritic field |
Off cells (and have more synapses per unit of visual field area) |
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Natural images contain more positive or negative contrasts at every scale |
Negative |
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The desity of synapses within a dendritic field is matched to what |
The information content of the field |
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What time of cells are found in the cortical area V1 (striate cortex) |
Simple cells |
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What do simple cells like |
Likes edges or elongated objects but specfici orientation |
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What is tuning in reference to simple cells |
Can make tuning curve based on how fast drops off as move to a different orientation |
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What is a narrowly tuned for simple cells |
Only respond to small changes (drops off quickly) |
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What does broadly tuned mean for simple cells |
Only respond to wide expanse of orientations (Drops off slowly) |
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Is this lower or higher SF |
Lower |
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Is this lower or higher SF? |
Higher |
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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) |
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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 |
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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 |
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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 |
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What is this? |
Can do same thing with orientation |
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What is this? |
This is length of receptive field |
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What is this? |
this is something adaptive persumably through evolution |
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For geniculostriate processing, the retinal image is analyzed into what |
Multiple components relevant to the organism |
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For geniculostriate processing is the analysis local or not |
Local |
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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) |
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Can RF properties be adapted to the statistical regularities of an organism's enviornment? |
It may |
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What receive local analysis of geniculostriate processing |
Higher cortical areas |
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Is cortex bigger in humans or in other animals |
Bigger in humans (It is more folded in humans) |
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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) |
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Is there specialized functions for each area of the cortex? |
Yes |
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What is MT specialized for? |
Motion (90% motion selective, 0% color selective) |
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What can an issue with MT lead to? |
Akinetopsia |
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What is akinetopsia |
Motion blindness |
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What is V4 specialized for |
Colro and form (5% motion selective, 60% color selective) |
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What does damage to V4 lead to |
*Achromatopsia *Hemichromatosia |
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What is achromatopsia |
No color viison |
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What is hemiachromatosia |
Color vision only on half of the VF |
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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 |
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What are the different pathways/streams from the occipital lobe? |
Dorsal/Ventral Pathway |
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What is the parietal stream? |
Where/How (More with spatial perception/layout) |
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What is the ventral stream? |
What (For object recognition) |
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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 |
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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) |
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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) |
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Removal of the parietal lobe tissue results in problems iwth what |
Landmark discrimination task |
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Removal of temporal lobe tissue resulted in problems with what |
Object discrimination task |
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How did they test the dorsal and ventral pathways neurological evidence |
*Behavior of patient DF *Other patients show opposite effects |
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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]](https://images.cram.com/images/upload-flashcards/85/31/37/24853137_m.png)
*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] |
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What does evidence show betwene ventral and dorsal pathways |
Evidence shows double dissociation |
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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 |
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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) |
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The dorsal stream is broadly specialized for what |
Action guidance |
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The ventral stream is broadly specialized for what |
Object perception and recognition |
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Are dorsal and ventral stream interconnected or not |
Interconnected |
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What is the visual hemifields like |
Crossover of 1 side of body to others |
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What are the crossover points in the brain like |
Crossover points from one side of the body to the other |
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What is the corpus callosotomy |
Split-brain procedure |
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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 |
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How many % of people are right handed |
90% |
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Is hemispheric specialization different for left handed people |
For some (but not all) |
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What is left hemisphere specialization like? |
*Specialization for language *Language production *Language comprehension |
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Is there language comprehension in the right hemisphere? |
Limited language comprehension in the right hemisphere: concrete words and simple sentences |
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What is Broca's area for? |
Lanugage production |
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What is Wernicke's area for? |
Language comprehension |
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Is there anatomical hemispheric asymmetries? |
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Is planum temporale (Wernicke's area) larger in left or right hemisphere? |
Left |
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Are right and left hemispheres of equal or unequal importance |
Equal |
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What is right hemisphere specialization |
Right hemisphere specialization for some nonverbal and spatial abilities |
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Can lateralization affect some clinical disorders |
Yes |
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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)]](https://images.cram.com/images/upload-flashcards/85/35/66/24853566_m.png)
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)] |
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What is the Block design task |
Arrange the blocks to match the design Performance is timed for each hand |
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What are the results from the block design task in a split brain patient? |
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What is pattern matching? |
*Briefly present visual patterns *Fixation selects hemisphere *Point to matching pattern *Hand selects hemisphere |
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Is there is a hemisphere that is better in pattern matching or equally good |
Both hemisphere are equally good |
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What is left-hemisphere processing for? |
*More piecemeal *Analytic *Special emphasis on temporal relationships |
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What is Right hemisphere processing for |
*More global *Holistic *Special emphasis on spatial relationships |
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Do the two hemispheres normally cooperate in processing information? |
Yes |
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What is the coordinate processing system of the two hemispheres run through |
Corpus callosum |
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The sharing processing between hemispheres often leads to what |
Better performance than if one hemisphere must perform the task alone |
