Week 5 Flashcards
The visual pathways has a :
Hierarchical
What are the 3 stages of visual path ways
early
mid-level
transform from image-based
what information is extracted from an image?
Line
colour
length
direction
what are spacial frequency tuned channels do?
carry the signal through the early stage and explain contrast sensitivity
What are objects constructed from?
component lines
What are Gobor-like receptive fields?
used to determine shape (colour, luminance, texture) of an object
which receptive field is used for localising points?
V1 receptive fields
What does the brain automatically do in a scene?
Segment scene into figures/objects and background
What is border ownership?
edges are assigned to objects
What receptive field is involved with border ownership
V2 receptive fields
what is grouping element contours?
Contours tend to be smooth in local regions so elements that extend a contour with minimal change of orientation are likely to be the same contour
What is Gestalt grouping principle?
the visual system automatically group together element into larger units (visual system fills gaps)
which receptive field response to shapes with convex projections
V4 Receptive field
What is texture segmentation ?
carving an image into a region of common texture properties
What is the amplitude of modulation?
the radial frequency of a pattern
What are the grouping principles?
Similarity and proximity
What is the grouping principle of similarity?
The tendency of two features to group together will increase as the similarity between them increases.
What is the grouping principle of proximity?
The tendency of two features to group together will increase as the distance between them decreases.
What are weaker grouping techniques?
Parallelism and symmetry
How to test for Global integration?
Use of multiple circles and determine which one is the mort absurd.
The more bumps on a circle in the Global integration task results in:
being easier to identify the target circle
how can you measure the sensitivity to structure in texture?
determining how many dot pairs need to have the correct orientation to discriminate structure from random.
What are the two stages of Glass texture?
Both dots need the same polarity to signal correct orientation
combine increments or decrements to get global pattrrn
what is the Ventral pathway of the brain?
Local stage = V1
global stage = V4
What impact on interpretation?
prior knowledge and experiences
What matters when predicting movement?
expectation matters
What is autism ?
development disorder associated with characterise psychological deficits
What does autism entail?
Social interactions
communication
repetitive behaviour
how is autism caused
Cortical damage in pattern processing
what are the visual aspects of autism
superior performance on tasks which involve focusing on parts of a complex stimulus
What motion threshold is associated with autism?
Poor global motion thresholds
what does EFT Mean?
Embedded figures test
What is the EFT?
is a visual serach task
Is global contour processing difference in ASD?
there is a stronger global contour integration in ASD
People that have a higher IQ have a:
Steeper gradient for integration of contour
What is a visual aura?
Unformed flashes of white and black light
darling zigzag
blurred or shimmering cloudy vision
hemianopsia
What is visual perimetry?
Measure of contrast sensitivity.
What are the two types of Visual perimetry ?
static target
Flickering target
what is Apperceptive Agnosia?
a person can not name, match or discriminate visual pressed objects
What is associative agnosia?
cannot use the derived representation to access stored knowledge of the objects function and association. can copy
What is hallmark of integrative agnosia?
an impairment in integrating elements, which are detected into a perceptual whole
What is integrative agnosia and the tendency to autism?
consistent with a weaker ability to use the global context when detecting stimuli
