Aberrant Dynamic Connectivity for Fear Processing in Anorexia Nervosa and Body Dysmorphic Disorder

Area of Science:

• Neuroscience
• Psychiatry
• Cognitive Science

Background:

• Anorexia nervosa (AN) and body dysmorphic disorder (BDD) share distorted appearance perceptions and negative emotions.
• Neural mechanisms of emotion processing in AN and BDD are underexplored and lack direct comparative studies.

Purpose of the Study:

• To investigate shared and distinct fronto-limbic connectivity patterns in BDD and AN.
• To compare neural phenotypes of emotion processing between BDD, AN, and healthy controls (HC).

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used in unmedicated participants with BDD (n=32), weight-restored AN (n=25), and HC (n=37).
• Participants viewed fearful faces and rated their fear response.
• Dynamic effective connectivity modeling focused on medial prefrontal cortex (mPFC), rostral anterior cingulate cortex (rACC), and amygdala.

Main Results:

• Healthy controls showed bidirectional mPFC-amygdala connectivity, strengthening over time.
• BDD participants displayed unidirectional mPFC-to-amygdala connectivity.
• AN participants lacked significant prefrontal-amygdala connectivity, showing weaker mPFC-to-amygdala connections than HC and BDD groups.
• mPFC-to-amygdala connectivity correlated with subjective fear, eating disorder, and anxiety symptom severity.

Conclusions:

• Findings suggest distinct neural underpinnings of emotion processing in BDD and AN, indicating a complex nosological relationship.
• These results offer insights into emotion regulation circuitry in these related disorders.
• The findings may inform current and novel therapeutic strategies for BDD and AN.