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13 Cards in this Set
- Front
- Back
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Give 5 examples of cognitive processes that follow the same basic organisational principle, and say what this principle is. |
1. attention 2. object recognition 3. decision making 4. thinking and reasoning 5. social cognition
neurons -> local networks -> systems |
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What are the cells involved in the advancing processing of shape information in the visual system? |
V1: simple cells Complex cells V2: contour cells V4: shape cells |
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Describe the experiment conducted by Wolfe and Cave, 1999, that investigated the binding problem of vision. |
1. display filled with red and yellow lines at various orientations with the letters P, O, C and K arranged randomly between two numbers. 2. instructed to fixate in the center and to try to recall what the flanking numbers were. 3. then asked (unexpectedly) to identify which of a selection of stimuli they had seen (e.g. R, Q, a red line at an unseen orientation and a yellow line at a familiar orientation) 4. participants often confused colours and orientations, demonstrating illusory perceived conjunctions |
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What are gnostic units? |
neurons or small populations of neurons that encode all properties associated with a given object (e.g. a grandmother cell) |
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Who famously dubbed gnostic units 'grandmother cells' and what was the point of this analogy? |
Lettvin, 1969 Wanted to highlight how ridiculous it was to suggest that we would have individual codings for everything and anything - it would be far too costly in terms of neurone resources. |
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What did we know about the visual system in the 1960s? (4) |
1. visual cortex is divided into multiple areas 2. receptive field size increases 3. complexity of preferred stimulus increases 4. lesions to temporal cortex impair object recognition |
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Where did Gross et al. (1972) report finding face-selective cells? |
In the temporal cortex: monkeys: TE/TEA humans: medial temporal cortex |
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What is the cardinal neurone/cortical hierarchy hypothesis? |
Neuronal preferences get progressively more complex as we progress through the visual processing system until neurons might encode individual objects |
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What are the two most significant problems with the cardinal neurone hypothesis? |
1. combinatorial explosion (there are too many possible objects that we can perceive for the number of neurons we have available) 2. the superposition problem (how do we perceive multiple objects at a time without confusing them) |
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What is the key premise of the rate-coding hypothesis? |
Multiple variables can be embedded in the firing rate of neurons via increasingly complex coding for increasingly complex stimulus dimensions. |
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Give the details of two studies that provide empirical support for the rate-coding hypothesis |
McClurkin et al., 1996 - the activity of cells predicted by the model when a person is shown a particular colour and pattern is almost identical to actual single-cell recordings.
Sugase et al., 1999
- monkeys were shown pictures of monkey faces displaying different emotions - there is an initial activity spike representing 'face' in general, but then the variations in activity in single neurons after this code for the specific emotional state that is being perceived |
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How does the rate-coding solution to the binding problem deal with the combinatorial explosion and superposition problems?
What major problem still remains? |
combinatorial explosion: better than cardinal neurone hypothesis
superposition problem: solved
how are the codes read? who detects them? |
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What is the temporal correlation hypothesis? |
FIND OUT |
