Chapter 3 - Excitatory and Inhibitory Pavlovian Conditioning Flashcards
What is excitatory pavlovian conditioning?
where a relationship is learned between the CS and the presentation of the US (the CS comes to predict the presence of the US, so we call this CS a CS+)
- the CS activates a “neural and behavioural” representation of the US. in the absence of the actual presentation of the US
- the conditioned response is therefore related to the US
What is one important thing to remember about excitatory pavlovian conditioning?
excitatory conditioning does not necessarily involve “excited” behaviour
- if the CR is a reduction in behaviour (ex. freezing), it is still considered excitatory
- can be appetitive or aversive
What is a conditioning trial?
the pairing of the CS and the US
What is a training session?
multiple conditioning trials
What is an intertrial interval (ITI)?
time in between each trial (usually longer than the ISI - otherwise there would be an inhibitory association)
What is an interstimulus interval (ISI)?
time between start of CS and start of US
What are the conditioning procedures for excitatory pavlovian conditioning?
- First order conditioning
a) short delayed conditioning (ISI < 1 min)
b) long-delayed conditioning (ISI > 5 min)
c) trace conditioning: CS and US not experienced simultaneously
d) simultaneous conditioning: CS and US turn ON and OFF simultaneously (no ISI)
e) backward conditioning: US is experienced first
- similar results in all 5 first order conditionings (except backwards which can be variable)
- CS predicts the onset of US in all cases
- differences between these are that they activate different brain regions
Describe the study performed by Bernstein in 1978 on conditioned taste aversion in children receiving chemo?
conditioning phase:
group 1: novel ice cream + chemo (21% chose ice cream)
group 2: new toy + chemo (67% chose ice cream)
group 3: new ice cream, no chemo (73% chose ice cream)
test phase:
give all the patients a choice: play a game or eat ice cream again
- calculate preference for eating ice cream
results: chemo = taste aversion
Why are control procedures needed?
- pseudoconditioning: change in responding to a stimulus whose presentations are intermixed with a US in the absence of an established association
- sensitization
What are the different kinds of control procedures?
- random control procedures: present the US periodically during both the CS and the ITI (this way the CS does not signal an increase in probability that the US will occur)
- explicitly unpaired control: present CS and US on separate trials (no conditioning will occur because they were never presented on the same trial)
What is a test trial?
presentation of the CS without the US
How do we measure conditioned responses?
- magnitude: size, vigour, length of CR (ex. drops of saliva)
- probability: % of trials where CR is exhibited (ex. eyeblink conditioning)
- latency: how soon after CS does a CR occur (ex. port-entry response)
What is inhibitory pavlovian conditioning?
a CS comes to predict the absence of a US (represented by CS-)
- can only occur if there is an expectation of a US
- US is more likely to appear when CS- is not presented
- CS will inhibit the behaviour that is elicited by the US
Describe examples of aversive conditioning and appetitive conditioning in both excitatory and inhibitory conditioning, respectively?
- aversive conditioning:
EC: CS+ associated with shock –> freezing
IC: CS- associated with no shock –> inhibits fear - appetitive conditioning:
EC: CS+ associated with food –> salivation
IC: CS- associated with absence of food –> frustration
What are the two inhibitory conditioning procedures?
- standard CI procedure (Pavlov)
a) type A - promotes excitatory conditioning
b) type B - CS+ paired simultaneously with CS-
- random switching between type A and type B introduces two types of learning at the same time - negative CS-US correlation
- CS- predicts the absence of US
- CS+ comes from environmental context
- the CS- decreases the probability that the US will occur
How can we measure inhibitory responses?
- bi-directional response systems
- certain response systems are bi-directional (look for opposite behaviour)
- some responses may have a low baseline or no true opposite - compound-stimulus (summation) test
Describe the study performed by Cole, Barnet and Miller (1997) on the summation test?
Phase 1: light --> shock (A+) light + sound --> no shock (Ax-) light + different sound --> shock (B+) Phase 2: measure how long it takes to accumulate 5 seconds of uninterrupted drinking time Result: light = no drinking (fear response) light + sound x = drinking (no fear) light + sound y = no drinking (fear response)
Describe the retardation of acquisition test performed by Cole, Barnet and Miller (1997)?
- rate of acquisition if excitatory conditioning should be slower for CI (ex. bell = no shock took longer to understand than now bell = shock)
What is the role of the CS-US contingency?
(Rescorla, 1968)
positive contingency: can predict (excitatory)
negative contingency: inhibitory
zero contingency: no prediction
- depending on how you pair them in time will determine the learned response
Why is it difficult to eliminate a conditioned response?
Because they are involuntary and hard to predict
What are two methods of eliminating a conditioned response?
- extinction
2. counterconditioning
What is extinction?
weakening of a learned response that occurs when the CS is repeatedly presented without the US
- works for most associations but can take a long time
- the passage of time can help recover some of the learned behaviour (spontaneous recovery)
- repeated spontaneous recovery results in less intense responses each time
- not dependable/doesn’t always work
- inconsistent initial conditioning makes a CR more resistant to extinction
What is spontaneous recovery?
often following a rest period, the CR (previously extinguished) will reappear
- original association is repressed, not unlearned (we learn something new)
- especially likely to reappear if extinction only happened in one context (context dependent)
What is counterconditioning?
Replacing an old response with a new, more productive response
- can do this by pairing CS with a positive stimulus (or an incompatible response)
- make sure new response is stronger than the originalCS (so that the opposite effect doesn’t happen)
What are some applications of counterconditioning?
- incompatibility method (Mary Cover Jones)
- little Peter and white rabbits - Threshold method
- systematic desensitization
