Although the amygdala is most know for its role in fear conditioning, several studies examining extinction have demonstrated increased amygdala activation to CS-no UCS association. For instance, successful fear extinction has been found to be correlated with increased amygdala activation. Additionally, other data suggest that specific activation of the lateral amygdala and the orbitofrontal cortex during extinction may be subserved by the modulation of the amygdala-orbitofrontal circuitry in the expression of fear responses. A large body of human studies has implicated the medial prefrontal cortex (mPFC) including the anterior cingulate cortex (ACC) in extinction learning. Similarly, findings from neuroimaging studies have shown a significant increase in vmPFC activation during extinction recall, as well as a positive correlation between signal change in vmPFC activation and degree of extinction retention. Further evidence from structural imaging indicates that vmPFC thickness is correlated with extinction recall. These data allude to the similar function of the human vmPFC and the rodent infra-limbic cortex in fear extinction.
Finally, these studies have also implicated the hippocampus in contextual extinction learning in humans. More recently, connectivity between dorsal anterior cingulate cortex (dACC), left posterior hippocampus, and right amygdala was exhibited during extinction. As a result, the interaction between the mPFC and the hippocampus may reflect context-specificity of extinction learning.