Neural correlates of emotional processing in panic disorder: A mini review of functional magnetic resonance imaging studies

Background: Panic Disorder (PD) is mainly characterized by recurrent unexpected panic attacks. Although the presence of emotional functioning deficits in PD is well established, their neuronal bases are still less known. Therefore, in this review, we aim to summarize the available functional Magnetic Resonance Imaging (fMRI) studies investigating the neural correlates associated with the processing of facial emotional expressions in patients with PD. Methods: A comprehensive search on PubMed was performed and 10 fMRI studies meeting our inclusion criteria were included in this review. Results: The majority of the studies reported selective deficits in key brain regions within the prefronto-limbic network in PD patients. Specifically, a mixed picture of hyperactivation and hypoactivation patterns were observed in limbic regions, including the amygdala and the anterior cingulate cortex (ACC), as well as in areas within the prefrontal cortex (PFC), either during negative or positive valenced stimuli, as compared to healthy controls (HC) or other anxiety disorders. Limitations: The limited number of studies and the clinical and methodological heterogeneity make it difficult to draw definite conclusions on the neural mechanism of emotional processing associated with PD. Conclusion: Although the results of the available evidence suggest the presence of selective dysfunctions in regions within the cortico-limbic network in PD patients during processing of emotional stimuli, the direction of these abnormalities is still unclear. Therefore, future larger and more homogeneous studies are needed to elucidate the neural mechanisms underpinning the emotional processing dysfunctions often observed in PD patients.