Differential alterations of resting‐state functional connectivity in generalized anxiety disorder and panic disorder

Summary & key facts

Researchers compared whole-brain resting-state functional connectivity in 21 people with generalized anxiety disorder (GAD), 18 people with panic disorder (PD), and 22 matched healthy controls. They used a new measure called scaled correlation to look for differences across the brain. GAD showed stronger connections between the hippocampus/parahippocampus and the fusiform gyrus. PD showed stronger connections between the somatosensory cortex and the thalamus. Each disorder’s connectivity changes correlated with how severe the patients’ symptoms were.

Key facts:

• The study compared resting-state functional connectivity in 21 GAD patients, 18 PD patients, and 22 matched control subjects.
• The authors used a novel metric called scaled correlation, which they reported as reliable and having higher statistical power for two-sample whole-brain FC tests.
• In GAD patients, the most significant increases in connectivity were between the hippocampus/parahippocampus and the fusiform gyrus.
• In PD patients, the most notable connectivity increase was between the somatosensory cortex and the thalamus.
• The disrupted connectivity patterns in each disorder correlated with that disorder’s symptom severity, indicating psychopathological specificity.

Abstract

Generalized anxiety disorder (GAD) and panic disorder (PD) are most common anxiety disorders with high lifetime prevalence while the pathophysiology and disease-specific alterations still remain largely unclear. Few studies have taken a whole-brain perspective in the functional connectivity (FC) analysis of these two disorders in resting state. It limits the ability to identify regionally and psychopathologically specific network abnormalities with their subsequent use as diagnostic marker and novel treatment strategy. The whole brain FC using a novel FC metric was compared, that is, scaled correlation, which they demonstrated to be a reliable FC statistics, but have higher statistical power in two-sample t-test of whole brain FC analysis. About 21 GAD and 18 PD patients were compared with 22 matched control subjects during resting-state, respectively. It was found that GAD patients demonstrated increased FC between hippocampus/parahippocampus and fusiform gyrus among the most significantly changed FC, while PD was mainly associated with greater FC between somatosensory cortex and thalamus. Besides such regional specificity, it was observed that psychopathological specificity in that the disrupted FC pattern in PD and GAD correlated with their respective symptom severity. The findings suggested that the increased FC between hippocampus/parahippocampus and fusiform gyrus in GAD were mainly associated with a fear generalization related neural circuit, while the greater FC between somatosensory cortex and thalamus in PD were more likely linked to interoceptive processing. Due to the observed regional and psychopathological specificity, their findings bear important clinical implications for the potential treatment strategy.

Topics

Anxiety, Depression, Psychometrics, Treatment, Cognitive Processes Functional Brain Connectivity Studies Neural dynamics and brain function

Categories

Cognitive Neuroscience Life Sciences Neuroscience

Tags

Anxiety Functional magnetic resonance imaging Fusiform gyrus Generalized anxiety disorder Hippocampus Medicine Neuroscience Panic disorder Psychiatry Psychology Psychopathology Resting state fMRI