DFG Research Unit 1581
Background
Extinction of classical conditioning has been studied experimentally for almost a century, since the classical reports of Pavlov’s appetitive conditioned responses in dogs. Compared to acquisition, however, our knowledge of the mechanisms of extinction is far more limited.
What is extinction?
Extinction is a reduction or loss in the strength or rate of a conditioned response when the unconditioned stimulus or reinforcement is withheld.
Learning and subsequent extinction of conditioned responses.
Erasing old associations?
Experimental data demonstrate that extinction does not simply erase the acquired excitatory association but that a second association is acquired during extinction instead, inhibiting the former learned excitatory behavior.
New Learning!
Extinction is believed to involve a new learning process that is different and more complex than the initial acquisition of the Conditioned stimulus (CS) - unconditioned Stimulus (US) - association. Extinguished responses do not disappear but can return following manipulations such as a change in context as in renewal paradigms.
Data obtained by these paradigms suggest that acquisition and extinction are organized by different neural systems (Herry et al., 2008; Quirk and Mueller, 2008)
A: an excitory association is acquired between stimulus and response (line with triangle). B: a second association is learned that inhibits the first one (line with bar at the end)- the stimulus no longer activates the Response. A: Renewal occurs – due to contextual cues the inhibitory association is not retrieved perfectly, therefore the response is shown again
Don't forget...
