In this model, a neutral cue or context can come to elicit a conditioned response when it is paired with an unconditioned stimulus. Learning extinction can also occur in a classical conditioning paradigm. They infer that inhibition derives from the ventromedial prefrontal cortex and suggest promising targets at the cellular level for new treatments of anxiety. A recent study in rodents by Amano, Unal and Paré published in Nature Neuroscience found that extinction of a conditioned fear response is correlated with synaptic inhibition in the fear output neurons of the central amygdala that project to the periaqueductal gray that controls freezing behavior.

Given the competing views and difficult observations for the various accounts researchers have turned to investigations at the cellular level (most often in rodents) to tease apart the specific brain mechanisms of extinction, in particular the role of the brain structures (amygdala, hippocampus, the prefrontal cortex), and specific neurotransmitter systems (e.g., GABA, NMDA).

Myers & Davis review fear extinction in rodents and suggested that multiple mechanisms may be at work depending on the timing and circumstances in which the extinction occurs. A third account concerns non-associative mechanisms such as habituation, modulation and response fatigue. However, there is debate over whether extinction involves simply 'unlearning' the unconditional stimulus (US) – Conditional stimulus (CS) association (e.g., the Rescorla–Wagner account) or, alternatively, a 'new learning' of an inhibitory association that masks the original excitatory association (e.g., Konorski, Pearce and Hall account). The dominant account of extinction involves associative models. Many anxiety disorders such as post traumatic stress disorder are believed to reflect, at least in part, a failure to extinguish conditioned fear. For example, after Pavlov's dog was conditioned to salivate at the sound of a metronome, it eventually stopped salivating to the metronome after the metronome had been sounded repeatedly but no food came.

In classical conditioning, when a conditioned stimulus is presented alone, so that it no longer predicts the coming of the unconditioned stimulus, conditioned responding gradually stops. When operant behavior that has been previously reinforced no longer produces reinforcing consequences the behavior gradually stops occurring. JSTOR ( July 2009) ( Learn how and when to remove this template message)Įxtinction is a behavioral phenomenon observed in both operantly conditioned and classically conditioned behavior, which manifests itself by fading of non-reinforced conditioned response over time.Unsourced material may be challenged and removed.įind sources: 'Extinction' psychology – news Please help improve this article by adding citations to reliable sources. This article needs additional citations for verification.

Extinction burst