Task 4 classical conditioning Flashcards
classical conditioning
form of learning, in which an animal learns that one stimulus (such as a doorbell) predicts an upcoming important event (such as delivery of food)
Unconditional stimulus
A cue that has some biological significance and in the absence of prior training naturally evokes a response
Unconditioned response
the naturally occurring response to an unconditioned stimulus)
Conditioned stimulus
A cue that is paired with an unconditioned stimulus and comes to elicit a conditioned response
Conditioned response
The trained response to a conditioned stimulus in anticipation of the unconditioned stimulus that it predicts
o Serves as preparation for upcoming events
Appetitive conditioning
Conditioning in which the US is a positive event (e.g. food)
o Strong conditioners
Aversive conditioning
US is negative event, learning to avoid or minimize the consequences of an expected aversive event
´Conditional emotional response
Technique where US is a shock which leads to freezing of CR
Eyeblink conditioning
A classical conditioning procedure in which the US is an airpuff to the eye and the conditioned and unconditioned responses are eyeblinks (CS is a tone)
Compensatory response
Compensate an event before it actually happens (e.g. lowering water level in a pool before heavy rain)
Compound conditioning
The simultaneous conditioning of two cues, usually presented at the same time (CR is faster established but when only one of them is used it doesn’t work)
Overshadowing
A effect seen in compound conditioning when a more salient cue within a compound acquires more association strength, and is thus more strongly conditioned, than does the less salient cue
Kamin’s Blocking effect
two ways of blocking 1. Being more salient (louder) 2. Getting there sooner (a prior trained CS can block learning about another because it already predicting 100% so there is no more space for another)
Blocking
A two phase training paradigm in which prior training to one cue (CS1 → US) blocks later learning of a second cue when the two are paired together in the second phase of the training (CS1+CS2 →US)
Mackintosh Theory
o CS modulation theory: the way attention to different CSs is modulated determines which of them become associated with the US. Predicts that salience of a tone as a potential CS will decease when the tone is present without any US (as tone develops history of predicting nothing)
Previously conditioned stimulus derives its salience from its past success as a predictor of important events & other co-occurring cues don’t get access to your limited pool of attention anymore
The Rescorla-Wagner Model of Conditioning
o Cues compete with one another for associative strength
Predicting error (Rescorla-Wagner)
the difference between what was predicted and what actually occurred
Error correction learning (Rescorla-Wagner)
A mathematical specification of the conditions for learning that holds that the degree to which an outcome is surprising modulates the amount of learning that takes place
Positive error: CS predicts nothing too little, but us is unexpectedly strong or unexpectedly occurs (increased association)
No error: CS predicts US, and predicted US occurs (no new learning)
Negative error: CS predicts US, but no US occurs (decreased association)
Associative weight (Rescorla-Wagner)
a value representing the strength of association between a CS and US (Rescorla-Wagner)
Gluck and Bower
Human conditioning study in which they tested with diseases and students had to predict with the help of symptoms which disease it is
o Attention shifting might be a limitation of all conditioning models
Cerebellum
o Purkinje cells: A type of large, drop shaped, and densely branching neuron in the cerebellar cortex
- One of the cerebellar deep nuclei where CS and US stimuli converge
CS input pathway
project first to the brain stem area pontine nuclei, which has different subregions for each kind of sensory stimulation.
o This signal travels up t the deep nuclei along axon tracts called mossy fibers which brands in two directions
One goes to interpositus nucleus
The other one projects toward the cerebellar cortex and across the parallel fibers and connects to the dendrites of the Purkinje cells
Closer look Pathways
o At the moment of activation of the Purkinje cell by the climbing fiber, all of the parallel fiber synapses that were recently active will undergo a long-term depression
This occurs because parallel fiber input activates metabotropic glutamate receptors. In addition to calcium coming from the climbing fibers starts Protein kinase C (PKC). This high level of PKC results in internalisation of the ionotropic AMPA glutamate channels
This produces long-term depression
Since our current concept of the climbing fiber function is that they convey an error signal, the granule cell to Purkinje cell synapses that were active at the time of the error will be inhibited
US input pathway
o US activates Inferior olive which in turn activates the interpositus nucleus.
o In addition a second branch of the pathway from the inferior olive projects up to the cerebellar cortex by means of the climbing fibers, which wraps around a Purkinje cell. Each climbing cell has a very strong excitatory effect on the Purkinje cells
