Motivation and emotion/Book/2026/Fear extinction

Fear extinction:
What psychological and neural processes underlie the extinction of fear responses?

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Overview

Figure 1. Rotating Image of Brain Regions

Imagine you're bitten by a dog. You might develop a fear response whenever you see a dog because the brain has learned:

Dog → Danger → Fear

If you consistently have positive encounters with dogs without any negative consequences, you will gradually learn:

Dog → No Danger → Safety

What are the psychological and neurological mechanisms involved?

Fear extinction is a decline in conditioned fear responses (CRs) following nonreinforced exposure to a feared conditioned stimulus (CS) (Myers, 2006). Extinction is not simply the erasure of a fear memory, it involves learning a new association that inhibits the orginal fear response.

If an individual experiences positive outcomes while facing the fearful stimulus without recieving any maladaptive consequences you are gradually learning a process called extinction learning. Cognitively, extinction occurs when the expected threatening outcome does not occur. Repeated safe experiences weaken the expression of fear responses and strengthen the safety association (Maren et al., 2013).

However, the orignal fear can remain. This is reiterated by renewal, where fear returns in different circumstances, reinstatement, where fear reemerges after experiencing the threat again, and spontaneous recovery, where fear returns after a period of time (Quirk & Mueller, 2007).

Several regions in the brain interact with fear extinction. The amygdala is essential in the attainment and expression of fear. The ventromedial prefrontal cortex (vmPFC) contributes to regulation of fear responses and the retrieval of extinction memories (Milad & Quirk, 2002). The hippocampus supplies contextual information, thus, helping decide if a previous threat should be percieved as dangerous or safe (Maren et al., 2013).

Therefore, fear extinction involves new inhibitory learning rather than the erasure of the original fear memory. The interaction between hippocampus, vmPFC, and amygdala provides individuals the ability to learn that prior threatening stimuli can be safe, resulting in a reduction of percieved fear responses when danger is not displayed.

Focus questions

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1. How does fear extinction change the way individuals respond to previously threatening stimuli?

2. What psychological processes contribute to the development of new safety associations during fear extinction?

3. How do the amygdala, vmPFC, and hippocampus interact to regulate fear extinction?

4. How does the context in which extinction occurs influence the persistece or return of fear?

5. Why might fear responses return after successful extinction, and what does this reveal about how fear memories are stored and regulated?

Understanding Fear Extinction

Fear [Remove bold] [Use an internal link - see Tutorial 2] is an intervening response that assists individuals in detecting and responding to context-dependent stimuli (Adolphs, 2013). Through the use of fear conditioning [Use an internal link - see Tutorial 2], neutral stimuli can have a maladaptive correlation with percieved danger, this results in a learned fear response. It is important to note that when the expected harm has failed to occur repeatedly, individuals can determine that the stimulus is not dangerous, this is a process identified as fear extinction [Use an APA style citation and move the doi to References]. However, extinction is not regarded as the deletion of the original fear; it is simply the formation of new safe inhibitory associations that aids in the reduction of fear. Extinction learning is influenced by contextual information, this helps identify if a past threatening stimuli should be percieved as dangerous or safe (Bouton, 2004; Quirk & Mueller, 2007; Maren et al., 2013). Having a greater understanding on these processes grants a foundation for analysing psychological and neuralogical mechanisms that allows fear responses to be reduced as well as explaining why fear has the potential of returning after successful extinction.

Formation of Fear and Fear Conditioning

Fear conditioning occurs during previous neutral stimuli becoming associated with a threatening event, consequently causing the stimulus to later trigger a fear response. This learned connection is essential for understanding how fear can be ultimately reduced through extinction (Quirk & Mueller, 2007).

Fear Extinction as New Learning

Fear Extinction is a result of previously threatening stimuli being repeatedly experienced without the expected threat. Instead of erasing the original fear memory, extinction allows learning new inhibitory safety associations, resulting in the individual to distinguish that the stimuli is no longer a predictive danger (Quirk & Mueller, 2007).

The Role of Context and Memory in Extinction

Extinction learning is influenced by the context in which it occurs. The brain uses situational information to determine if a prior threatening stimuli should be percieved as unsafe or secure. This assists in clarifying why fear can return when the stimulus has appeared during a variety of scenarios (Bouton, 2004).

Aurthor note: Add two or more dot points in each subtitle to further reinforce how does fear extinction change the way individuals respond to previously threatening stimuli.

Psychological Processes Underlying Fear Extinction

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Inhibitory Learning And The Formation of Safety Associations

Fear extinction is acknowledged as a process of new inhibitory learning, instead of the complete deletion of the original fear memory. As previously stated, when a past dangerous stimuli is consistently presented without the expected maladaptive outcome, the individual begins to associate that the stimuli is safe. Let's use the dog scenario again; for example, someone who is afraid of dogs after being bitten may slowly learn through positive encounters that dogs do not necessarily anticipate danger. This new association inhibits the expression of the original fear response, allowing for adaptive behaviour regardless of the persistence of the orginal fear memory (Quirk & Mueller, 2007; Furini et al., 2014).

Prediction Error and Expectancy Violation

Expectancy violation is an integral psychological mechanism of extinction. This occurs when the outcome an individual expects differs from what actually happens. During the occurance of extinction, an individual may predict a maladaptive outcome but consistently experience its absence, this is known as prediction error. This mismatch causes prediction error, notifying that previous expectation about threats need to be updated. Therefore, greater expectancy violation can increase extinction learning by motivating the individual to reconsider their beliefs between the relationship of the stimulus and threat (Craske, 2015).
Aurthor note: Add two dot points exploring how expectancy violation and prediction error contributes to the development of new safety associations during fear extinction.

Context, Memory Retrieval and The Return of Fear

Context and memory retrieval is another process that influences extinction learning significantly. The learned safety association during extinction does not automatically replace the orgianl fear association; rather, the brain must retrieve the appropriate memory depending on the context of the situation. Ultimately, fear has the potential to return through processes such as renewal, when the stimulus is engaged in different contexts, or spontaneous recovery, when addequate time has passed. This reinforces that successful extinction depends on both the safety of the stimulus and the ability to retrieve that safety learning when it is required (Maren et al., 2013).
Aurthor note: add two comprehensive dot points further exploring renwal and spontaneous recovery for focus question 2.

Neural Mechanisms of Fear Extinction

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The Amygdala: Acquisition and Expression of Fear

The amygdala plays an integral role in the acquisition and expression of conditioned fear. During fear conditioning, the basolateral amygdala helps establish associations between previous neutral stimulus and an averisive outcome, additionally, the central amygdala contributes to the expression of physiological and behavioural fear responses. When fear extinction is occurring, the amygdala remains involved due to the original fear association staying. However, extinction-related neural changes allows for the reduction of fear expression when the stimulus is no longer linked to danger (Quirk & Mueller, 2007).
Aurthor note: Talk about what exactly is the amygdala i.e., what it is, regions in it, hormones/chemical responses it releases, and how that relates to how fear is acquired and how it is expressed.

The vmPFC: Inhibition and Retrieval of Extinction Memories

The ventromedial prefrontal cortex (vmPFC) is vital for regulating fear following extinction learning. Instead of removing the original fear association, the vmPFC contributes to the retrieval of newly learned safety associations and can employ inhibitory influence over amygdala-based fear responses. Literature by Quirk and Mueller (2007) identified that activity within the medial prefrontal cortex has a positive correlation with successful extinction memory retrieval, signifying the importance in suppressing prior conditioned fear.
Aurthor note: find more literature to back up how the vmPFC has a positive correlation with successful extinction.

The Hippocampus: Contextual Regulation of Fear Extinction

The Hippocampus delivers significant contextual information crucial for identifying if a previously threatening stimulus should be interpreted as dangerous or safe. It has a positive relationship with the vmPFC due to it classifying in which extinction learning occurred and assist in guiding retrieval of the appropriate memory. This contextual processing further explains why fear can return when a previously feared stimulus is encountered outside the extinction context, demonstrating that extinction is highly dependent on context-sensitive memory retrieval (Maren et al., 2013).

Table 1. Brain Regions Neural Mechanisms And Their Relation to Fear Extinction


Brain Region / Mechanism	Role In Fear Extinction	Neural Mechanism
Amygdala	Involved in the acquisition and expression of conditioned fear, while also participating in extinction learning.	During extinction, changes within the amygdala support the learning of new extinction associations. Extinction does not simply remove the original fear association.
vmPFC	Supports the inhibition and retrieval of extinction memories.	The vmPFC integrates information about the stimulus and extinction learning and can exert regulatory influences over amygdala activity.
Hippocampus	Provides contextual information that helps determine whether a previously threatening stimulus is currently safe.	The hippocampus communicates contextual information to prefrontal and amygdala circuits, helping distinguish the extinction context from contexts associated with threat.
Amygdala-vmPFC Interaction	Allows the brain to regulate the expression of previously learned fear.	The vmPFC can influence amygdala circuits involved in fear expression, supporting the retrieval of the safety association.
Hippocampus-vmPFC Interaction	Allows extinction memories to be retrieved appropriately according to context.	Contextual information from the hippocampus helps the vmPFC determine whether extinction or fear memories should guide behaviour.

The Return of Fear Following Extinction

Renewal: The influence of Context on Fear
Fear can return when a previously extinguished stimulus is ecountered in a context that differs from where extinction learning occurred. This pheomenon is known as renewal, it demonstrates that extinction does not erase the orginal fear memory. Instead, the brain retains both the original fear association and the newer safety association, with contextual information influencing which memory is expressed. The hippocampus is important in providing contextual information that helps determine whether the stimulus should be interpreted as threatening or safe (Bouton,2004; Maren et al., 2013).

Reinstatemnt: The Return of Fear Following Exposure to Threat

Reinstatement occurs when a fear response returns after an individual expereinces the aversive event again following extinction. For example, if someone successfully extinguishes their fear of dogs but is subsequently bitten by a dog, their fear of dogs may return. This implies that extinction learning remains vulnerable to subsequent threatening experiences, which can reactivate or strengthen the orginal fear association (Quirk & Mueller, 2007; Maren et al., 2013).

Spontaneous Recovery and Persistance of The Original Fear Memory

Spontaneous recovery refers to the return of a previously extinguished fear response following the passage of time. This phenomenon provides further evidence that extinction does not permantly elimate the orginal fear memory. Rather, extinction creates a competing inhibitory safety memory that can weak or suppress fear under appropriate conditions. As time passes, the orignal association may regain influence, demonstrating the enduring nature of fear memories and the importance of continued extinction learning (Bouton,2004; Quirk & Mueller, 2008).

Case study: Return of fear through context change

Vansteenwegen et al. (2004) studied human participants using fear-conditioning paradigm. Participants first learned to associate a neutral visual stimulus with an aversive loud noise. During extinction, the stimulus was repeatedly presented without the noise, causing their fear responses to decrease. However, extinction took place in a different context from where the original fear was learned.

When participants were ultimately returned to the original fear-conditioning context, their conditioned fear response returned. This was identified through an increase in electrodermal responses and increaased expectations that the negative outcome would occur. Particpants who experienced acquisition extinction and testing in the same context did not show the same recovery of fear.

This demonstrates evidence of renewal, showing that extinction does not erase the orginal fear memory. Instead, extinction appears to create a new safety association that is strongly influenced by context. When the individual returns to a context associated with the original threat, the orginal fear memory can regain control over behaviour. This finding also highlights the importance of the hippocampus and contextual processing in determining whether fear or safety memories are retrieved.

Test your knowledge Author note: add more questions in the chapter

Conclusion

Fear extinction is a complex learning process through which individuals learn that a previously threatening stimulus no longer predicts danger. Rather than erasing the original memory of fear, extinction involves the development of a new inhibitory safety association that reduces the expression of fear responses (Quirk & Mueller, 2007). Physiological processes, such as expectancy violation, prediction error, and contextual memory retrieval, contribute to this new learning by allowing individuals to update their expectations about potential threats. At a neural level, interactions between the amygdala, vmPFC, and hippocampus support regulation and retrieval of extinction memories. The amygdala contributes to fear expression, while the vmPFC supports fear inhibition and the hippocampus provides contextual information to guide memory retrieval (Maren et al., 2013). Importantly, extinction does not permanently eliminate fear,as demonstrated by renewal, reinstatement, and spontanous recovery. Overall, understanding these psychological and neural mechanisms depict why extinction can reduce fear while leaving the original fear memory intact.

References

Adolphs, R. (2013). The biology of fear. Current Biology, 23(2), R79–R93. National Library of Medicine. https://doi.org/10.1016/j.cub.2012.11.055

Bouton, M. E. (2004). Context and behavioral processes in extinction. Learning & Memory, 11(5), 485–494. https://doi.org/10.1101/lm.78804

Craske, M. (2015). Optimizing exposure therapy for anxiety disorders: An inhibitory learning and inhibitory regulation approach. Verhaltenstherapie, 25(2), 134–143. https://doi.org/10.1159/000381574

Furini, C., Myskiw, J., & Izquierdo, I. (2014). The learning of fear extinction. Neuroscience & Biobehavioral Reviews, 47, 670–683. https://doi.org/10.1016/j.neubiorev.2014.10.016

Maren, S., Phan, K. L., & Liberzon, I. (2013). The contextual brain: Implications for fear conditioning, extinction and psychopathology. Nature Reviews Neuroscience, 14(6), 417–428. https://doi.org/10.1038/nrn3492

Milad, M. R., & Quirk, G. J. (2002). Neurons in medial prefrontal cortex signal memory for fear extinction. Nature, 420(6911), 70–74. https://doi.org/10.1038/nature01138

Myers, K. M. (2006). Different mechanisms of fear extinction dependent on length of time since fear acquisition. Learning & Memory, 13(2), 216–223. https://doi.org/10.1101/lm.119806

Quirk, G. J., & Mueller, D. (2007). Neural mechanisms of extinction learning and retrieval. Neuropsychopharmacology, 33(1), 56–72. https://doi.org/10.1038/sj.npp.1301555

Vansteenwegen, D., Hermans, D., Vervliet, B., Francken, G., Beckers, T., Baeyens, F., & Eelen, P. (2004). Return of fear in a human differential conditioning paradigm caused by a return to the original acquistion context. Behaviour Research and Therapy, 43(3), 323–336. https://doi.org/10.1016/j.brat.2004.01.001

External links

Provide external links to highly relevant resources such as podcasts and videos, news articles, and professional sites. Use sentence casing and alphabetical order.

Hippocampus (Cleveland Clinic)
How Prediction Errors Shape Perception, Attention, and Motivation (National Library of Medicine)
Reinstatement of Fear Responses in Human Aversive Conditioning (ScienceDirect)
Renewal Effect - (Alleydog)
Spontaneous Recovery (ScienceDirect)
The Basolateral Amygdala: The Core of a Network for Threat Conditioning, Extinction, and Second-Order Threat Conditioning (National Library of Medicine)
The learning of fear extinction (Science Direct)

Aurthor note!!!* The code for the chapter layout has seemed to glitch for me and other students. For some reason my focus questions have my headings in the box as well for some reason even though they aren't

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