Week 11 Flashcards
(27 cards)
Describe the motion coherence task
Where you have to say what direction the dots are moving in too find peoples threshold of where they start to see motion
How can you make the motion coherence task harder?
By reducing the coherence (adding in noise dots)
What conditions can higher motion coherence be seen in?
Williams syndrome
Autism
Dyslexia
Why is there an elevated motion coherence threshold in dyslexia? Explain evidence for this
Due to atypical magnocellular function; reduced size of cells in magnocellular
What are the 3 categories autism is classed into?
- Differences in social communication and interaction
- Restrictive and repetitive behaviours/interests including sensory processing differences
- Elevated motion coherence thresholds
Why do autistic people have elevated motion coherence?
Because they have difficulty integrating parts into the whole
What could explain autistic peoples bias to local information?
They have reduced functional connectivity, stronger local than long-range neural connections and reduced top-down modulation
Can the weak central coherence account explain reduced susceptibility to visual illusions in autism?
Yes > proposed that autistic people are able to process individually the circles in the middle and they are not influenced by the context
Why are motion coherence thresholds elevated in autistic children?
Reduced sampling
Higher internal noise
Reduced segregation of signal from noise
How do children perform in the direction integration task?
Children are still able to work out the overall motion direction
Assuming the magnocellular account is correct how would you expect dyslexic people to do in each task?
Reduced amount of mango cells = elevated thresholds and reduced sensitivity in both of these tasks
Assuming the weak central coherence account is correct, how would you expect autistic people to do in each task?
Hard to focus on dot and depends on coherence level
What is the difference between the tasks in terms of processing requirements?
Motion coherence task - need integration and segregation
Direction integration task - need integration, but not segregation
What is the purpose of equivalent noise modelling?
To estimate a Childs sampling ability and internal noise
How did autistic children perform in comparison to non autistic children in the motion coherence task?
Autistic children can combine more dots and can work out overall motion in a greater range than the non-autistic children
What are the implications of the motion coherence task for the weak central coherence theory?
Goes against weak central coherence theory > autistic children are good at combining motion signals, but the benefit is not also seen in the motion coherence task where they have to filter out irrelevant stimuli
What stream is slower to develop - dorsal or ventral?
Dorsal
Is the dorsal stream a single pathway?
No, its interlinked with overlapping networks = allows room for neural underpinnings in different developmental conditions
Name a challenge of dorsal stream tasks
Not all tasks are impaired in neurodevelopment conditions - what about enhanced performance?
What is the pattern glare test?
A task to show some people are more sensitive to some types of information compared to others
Name some common triggers of visual discomfort
Repeating/striped patterns, high contrast patterns, certain colour contrasts, flickers
What is photosensitive epilepsy?
Seizures that are triggered by visual stimuli
What is a migraine?
Severe prolonged headaches with a tendency for nausea, photophobia and phonophobia
How does chromaticity separation affect discomfort ratings and EEG measures?
Chromaticity separation leads to greater discomfort; large chromaticity separation leads to more negative amplitudes in general
