Is movement across the retina necessary for motion perception?
No as tracked objects still appear to move
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Is movement across the retina SUFFICIENT for motion perception?
No as the world stays still when we move our eyes
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What is the main concept of Helmholtz Outflow?
An efferent signal moves the eye muscles, a copy of this signal is sent to the comparitor. The retinal movement is also sent to the comparitor which is compared against the copy
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Which theory wins when the world stays still as we move our eyes over a stationary scene?
Both
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What is the main concept of Sherrington Inflow?
An efferent signal moves the eye muscle. The eye muscle movement signal is sent to the comparitor. The comparitor compares the eye muscle movement signal with retinal movement
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Which theory wins when we observe a moving object with stationary eyes and the object moves?
Both
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Which theory wins when the afterimage moves as we make eye movement?
Both
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Which theory wins when the world moves as we poke our eye with our finger?
Helmholtz Outflow
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Which theory wins when the afterimage DOESN'T MOVE when we poke our eye in DARKNESS?
Helmholtz Outflow
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Which theory wins when the world moves even when the eye is prevented from moving? (curare)
Helmholtz Outflow
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When building a motion detector, why would a delay be used?
To indicate direction. A detector without a delay would respond to A->B aswell as B->A
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In a movement detector, what is 'AND'?
Excitatory
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In a movement detector, what is 'DELAY'?
Inhibitory
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Which brain area shows nearly EVERY cell to be direction selective?
V5/MT
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How does a 'ratio' model delay detector work?
An array of receptors on the retina, a signal sent across the array stimulating other receptors reaching nodes at same time due to staggering
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In which animal are GANGLION cells directionally selective?
Rabbit
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In orientation columns, what kind of activation is represented?
A pinwheel of activation
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What happens at equiluminescence?
Motion slows/disappears
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What are directionally selective cells mostly driven by?
Luminance edges, not colour
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In stroboscopic movement, what is the optimal time inbetween presentations for movement?
60ms
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What else affects apparent motion?
Colour and shape
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In the Ternus dispay, what does a short ISI create?
Element motion
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In the Ternus dispay, what does a long ISI create?
Group motion
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What is the autokinetic effect?
A stationary spot of light in total darkness APPEARS to move
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What is induced movement?
e.g blutack on the TV
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What is the aperture problem caused by?
The direction of motion of a straight line is AMBIGUOUS. An infinite set of physical motions
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How is ambiguity in the aperture problem resolved?
Rely on local 2D features (and 'end' stopping cells sensitive to lines and corners)
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What model does motion of plaids support?
Intersection of constraints model
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What do V1 neurons respond poorly to?
Extended contours
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Other cards in this set
Card 2
Front
Is movement across the retina SUFFICIENT for motion perception?
Back
No as the world stays still when we move our eyes
Card 3
Front
What is the main concept of Helmholtz Outflow?
Back
Card 4
Front
Which theory wins when the world stays still as we move our eyes over a stationary scene?
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