Cortical morphometric predictors of autonomic dysfunction in generalized anxiety disorder

Area of Science:

• Neuroscience
• Psychiatry
• Autonomic Physiology

Background:

• Generalized anxiety disorder (GAD) is associated with autonomic dysfunction, specifically decreased vagally-mediated heart rate variability (vmHRV).
• Neurostructural abnormalities, particularly in brain morphometry, are also observed in GAD and correlate with vmHRV in healthy individuals.

Purpose of the Study:

• To investigate the hypothesis that specific focal abnormalities in cortical structure in GAD patients underlie their decreased vmHRV.
• To explore the relationship between cortical thickness in emotion-regulating brain regions and vmHRV in GAD.

Main Methods:

• Structural magnetic resonance imaging (sMRI) was used to assess cortical thickness in adult female GAD patients (n=17) and matched controls (n=18).
• vmHRV was quantified from continuous pulse oximetry, and symptoms were characterized.
• Cortical reconstruction was performed using FreeSurfer, with analysis focused on brain regions involved in vagal control.

Main Results:

• GAD patients exhibited cortical thinning in the left rostral anterior cingulate cortex, left medial orbitofrontal cortex, and right isthmus cingulate gyrus compared to controls.
• Anxiety symptom severity negatively correlated with cortical thickness in the left medial orbitofrontal cortex and right isthmus cingulate gyrus.
• GAD patients displayed reduced resting vmHRV, and in controls, left caudal anterior cingulate cortex thickness positively correlated with vmHRV.

Conclusions:

• Findings confirm structural abnormalities in cortical areas crucial for emotion regulation and cognition in GAD.
• Abnormal anterior cingulate cortex integrity may contribute to the psychophysiological manifestations of GAD.
• Targeting the anterior cingulate cortex could potentially normalize autonomic function in GAD patients.