5. Classical Conditioning Flashcards

1
Q

problem

A

classical conditioning is likely to depend on changes in synaptic plasticity - but there are trillions of synapses in the brain so where do we look?

  • need to make problem simple
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2
Q

how do we make understanding learning simple?

A

pick a simple form of learning - classical conditioning - hoping that there are fewer synapses involved

  • gives us a chance to identify them
  • understanding simple behaviour could help us understand more complex
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3
Q

unconditional stimulus (US)

A

(food/airpuff) produces the unconditioned response (UR)

  • not learnt
  • before training
  • e.g. salivation/shut NM
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4
Q

conditioned stimulus (CS)

A

paired with the US (bell/tone)

  • initially produces no response or an irrelevant response
  • eventually leading to conditioned response (CR)
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5
Q

conditioned reflex/conditioned response (CR)

A

CS produces conditioned response (after training)

e.g. tone produces salivation without the presence of food

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6
Q

eye blink conditioning

A

US is usually a puff of air into the eye (periorbital shock)

  • CS is usually a tone
  • UR and CR are movements of eye lid to protect eye
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7
Q

nictitating membrane response (NMR)

A

some animals have a third eyelid

  • this can also be conditioned but the animal has no voluntary control over its movement
  • very low level of spontaneous activity
  • SIMPLE
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8
Q

what happens in NMR

A

day 1 - NM stationary until US (air puff)
day 2 - NM moving before US = CR
day 5 - NM moves well before US, shutting to protect eye preemptively

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9
Q

eye blink conditioning features

A
  • US overlaps with CS = delay conditioning - gap between the end of the CS and the start of the US (trace conditioning) - more neural structures = delay
  • CR does not effect US = closing the eye has no affect on the US, otherwise its avoidance learning
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10
Q

forebrain?

A

Mauk and Thompson (1987)

  • delay in NMR conditioning still possible in rabbits lacking either hippocampus or cortex
  • also possible with rabbits who have forebrain separate from brainstem and cerebellum (decerebrate)
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11
Q

brainstem and cerebellum?

A

Thompson (1983)

  • technique 1 = electrophysiological mapping during conditioning.
  • recorded from multiple units in cerebellar cortex and deep cerebellar nuclei
  • unpaired control condition in which CS’s and US’s are presented as frequently as in training condition but unrelated (no neural response)
  • when paired, units increase responding as CR develops
  • but recording does not establish a causal role (need lesions)
  • technique 2 = first large lesion (through cerebellum and underlying brainstem) of entire cerebellum plus output (deep cerebellar nuclei)
  • CR abolished and cannot be relearnt
  • similar results when study focused on deep cerebellar nuclei
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12
Q

where are lesions in the deep cerebellar nuclei successful at abolishing CR

A

Yeo et al (1985)

  • lesions confined to the anterior portion of deep cerebellar nucleus (anterior interpositus nuclei) are effective
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13
Q

hippocampus?

A

Weiskrantz and Warrington (1979)
- patients with anterograde amnesia (damage to hippocampus) showed clear evidence of learning even though patients couldn’t remember apparatus

Gabrieli et al., (1995)

  • verified damage to medial temporal lobe (contains hippocampus) compared to control
  • rates of conditioning the same for both groups

Squire et al (1993)
- LTM is divided between conscious memory for facts and non-conscious memory (skill, habit learning, classical conditioning and learning)

  • does not depend on hippocampus and surrounding tissue
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14
Q

lesions: behavioural effects

A
  • after lesioning there is selective loss of the CR, but UR not affected
  • lesion does NOT produce a simple motor deficit
  • effects of unilateral lesions are unilateral, can do it to the other eye and get the same response (Yeo et al., 1987)
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15
Q

its loss of memory trace

A

lesions dont cause: (Thompson, 1983)

  • paralysis = UR still evident (e.g. NM shutting)
  • deafness = unilateral lesions affect conditioning of ipsilateral eye
  • loss of conditioned response appears to be genuine loss of the memory trace (the engram)
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16
Q

engram

A

memory trace