L8: Deconstructing fear memory Flashcards
what are the 2 main treatments for people with anxiety disorders?
extinction & reconsolidation
what can you say about the prevalence of anxiety disorders?
- leading form of mental illness worlwide
- 60m in europe
what are anxiety disorders? what lies at their core?
- conceptualized as irrational and learned fears
- associative fear memory lies at core
in what paradigms did emotional memory play a big role? in which didnt it?
big role: psychoanalysis, CBT
tiny role: behaviourism, biological psychiatry
how does fear conditioning work?
when a conditional stimulus (something neutral) is associated with an unconditional aversive stimulus (like a shock) which then leads the neutral something to always elicit that fear
- fear memory is strong - generalizes over time, context and stimuli
- “normal” fears have similar neurobio processes as irrational fears
- strong fear memory is functional and taps into one of the most important survival circuits (we want to predict)
- but can become irrational -> ADs
do people w ADs realize their fears are irrational?
usually yes!
except when theyre actually confronted with the “threat”, then they fully believe they’re in danger
what is the principle of extinction?
learning not to fear!
its unassociating the conditioned stimulus (spider) from the unconditinal stimulus (shock) so that conditioned fear response to CS dissapears
what is the spontaneous recovery response?
that if you induce extinction learning in an animal/hulman you need to repeat it shortly after, otherwise the fear will come back
if you leave too much time between extinction sessions and then you give the unconditioned stimulus again, the US - CS association will come back strong again (person will immediately go back to becoming scared from CS again
how is fear relapse explained by biology?
during extinction, inhibitory memory is formed in hippocampus, vmPFC
but fear memory stored in amygdala remains intact and may resurface
how does traditinional vs modern learning theory explain fear?
Traditional: Habituation, CS (sound) -> no CR (fear)
Modern: Learning, CS (sound) -> no US (shock) . feel, think and act is the feared stimulus (sound) is followed by a catastrophe
how does traditional vs contemporary theory explain exposure therapy?
traditional: habituation! (CS-> no CR)
contemorary: learning (CS-> no US) (basically you stop feeling, thinking, and acting as if the feared stimulus is followed by a catastrophe)
According to lecture, how can you optimize exposure treatment?
- design exposure that violate expectancies: like probability of expected negative outcome (US), intensity of anticipated catastrophe, extent to which catastrophe is manageable all these expectations need to violated
- focus on learning (mismatch, prediction error), condolidation, and retreival
How effective is exposure therapy?
- many patients benefit
- but long term effects are weak:only 38% profit at long term
what is exposure therapy?
- a way of reduceing conditional fear reaction
- clinical equivalent of extinction: CS (the thing you’re afraid of that was initially neutral, like a dog) is repeatedly presented in the absence of the associated aversive event (the US)
briefly explain the classical conditioning model
a neutral stimulus is conditioned (so it becomes the CS) by always associating an unconditioned stimulus with it (like an aversive sound). the unconditioned response that initially comes after exposure to the unconditioned stimulus, starts to automatically come after the CS as well, meaning it becomes a conditioned response to the CS.
for this the CS, or the neutral stimulus like a blue square, needs to be a reliable predictor of the US, aversive sound, so that there is an association between the memory representation of the CS and US (presentation of the blue square, CS, always activates the memory of the aversive sound, US, which then elicits fear (CR))
what is the inhibitory learning model?
- central to extinction and exposure therapy
- mean that the original CS-US (dog - biting) association learned during fear conditioning is not erased, rather its left intact as new, secondary inhibitory learning about the CS-US develops - specifically that the CS no longer predicts the US
- after exctinction: the CS (dog) posesses 2 meanings: its original excitatory meaning (CS-US) as well as an additional inhibitory meaning (CS-no US)
how can conditioned fear response come back?
- passage of time = spontaneous recovery
- leaving the therapeutic context = renewal
- re-exposure to aversive event = reinstatement
- new learning experience - rapid reacquisition
basically extinction does not generalize over time & context (as opposed to acquisition) !
what are the cons of the inhibitory learning in exposure therapy?
even though fear subsides with enough trials of the CS followed by no US (the inhibitory meaning), there is retention of at least part of the original (CS-US) association (its not forgotten so to say)
this can lead to:
- spontaneous recovery: passage of time
- renewal: changing of context. if surrounding context is changed between extinction & retest then renewal of conditional fear. aka fear extinction appears to be specific to the context in which extinction occurs (so if exposure therapy is completed in only one or a few limited contexts, then fear is likely to return when the CS is encountered in a different context)
- reinstatement: if re-exposure to aversive event
- rapid reacquisition of the CR: if new learning experience with CS-US pairings
what do habituation models state about exposure therapy?
- rests upon fear reduction during exposure trials as a critical index of therapeutic change
- posit that fear reduction during an exposure trial is a necessary precursor to subsequent, longer lasting cognitive changes in the perceived harm associated w the phobic stimulus
- while inhibitory learning models do not emphasize fear reduction
why does the inhibitory model on extinction not emphasize fear reduction to measure therapeutic change?
because fear reduction at completion of exposure therapy does not seem to predict the amount of fear expressed at the follow up extinction retest
this is because outward expression of fear and conditional automatic associations may not always change in concordance
what are the 8 exposure therapy optimization techniques that enhance inhibitory learning?
- expectancy violation
- deepened extinction
- occasional reinforced exctinction
- removal of safety signals
- variability
- retrieval cues
- multiple contexts
- affect labeling
what is the expectancy violation optimization technique?
- premise: mismatch between expectancy & outcome is critical for new learning & for dev of inhibitory expectancies that will compete w excitatory expectancies (CS-US expectancy)
- the more expectancy can be violated by experience, the greater the inhibitory learning
- client has to identify the US (aversive sound, biting, humiliation) when predicting the expectancy to be violated
- end of exposure trial determined by conditions that violate expectancies (social situation where there is no rejection), not by fear recdution
- so you ask participants to judge what they leared regarding the non-occurence of the expected feared event (US) and how violated their expectations were (aka you’re mentally rehearsing the inhibitory CS-no US association by asking the patient to reflect on it)
- key aspect: bring attention to both the CS (social interaction) and the non-occurence of the US (social rejection)
- graduated exposure may be used (like longer trials each time ex for fear of heights u may ask the client to stay 5 sec longer on the balcony each time, even though fear may not reduce each time. u do it based on time not based on fear reduction)
- cognitive strategies that reduce expectancy prior to extinction can negatively impact extinction learning (things like reducing probability overestimation (eg i am unlikely to be bitten by a dog)
what is the deepened exctinction technique?
- either multiple fear CSs are first extinguished separetly before being combined during extinction, or a previously extinguished cue is paired with a novel CS
- both feared stimuli must predict the same US (ex: one type of spider and another type of spider are both associated with the US of being bitten)
- been shown to reduce spontaneous recovery & reinstatement
what is the occasional reinforced extinction technique?
- involves occasional CS-US (dog - biting) pairings during extinction training
- works because expectancy violation effect (if CS sometimes leads to US and sometimes not so ur less likely to expect the next CS to predict the US)
