Abnormal spontaneous brain activity in patients with generalized anxiety disorder revealed by resting-state functional MRI

BackgroundWorrying has been suggested to prevent emotional and elaborative processing of fears. In cognitive-behavioral therapy (CBT), generalized anxiety disorder (GAD) patients are exposed to their fears during the method of directed threat imagery by inducing emotional reactivity. However, studies investigating neural correlates of directed threat imagery and emotional reactivity in GAD patients are lacking. The present functional magnetic resonance imaging (fMRI) study aimed at delineating neural correlates of directed threat imagery in GAD patients.MethodNineteen GAD patients and 19 healthy controls (HC) were exposed to narrative scripts of either disorder-related or neutral content and were encouraged to imagine it as vividly as possible.ResultsRating results showed that GAD patients experienced disorder-related scripts as more anxiety inducing and arousing than HC. These results were also reflected in fMRI data: Disorder-related v. neutral scripts elicited elevated activity in the amygdala, dorsomedial prefrontal cortex, ventrolateral prefrontal cortex and the thalamus as well as reduced activity in the ventromedial prefrontal cortex/subgenual anterior cingulate cortex in GAD patients relative to HC.ConclusionThe present study presents the first behavioral and neural evidence for emotional reactivity during directed threat imagery in GAD. The brain activity pattern suggests an involvement of a fear processing network as a neural correlate of initial exposure during directed imagery in CBT in GAD.

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The Association Between Generalized Anxiety Disorder and Resting-State Prefrontal Cortex Oxygenation Is Modified by Self-Reported Physical Activity: Results From The Irish Longitudinal Study on Ageing

The Journals of Gerontology Series A ◽

10.1093/gerona/glab090 ◽

2021 ◽

Author(s):

Cillian P McDowell ◽

Louise Newman ◽

Derek C Monroe ◽

John D O’Connor ◽

Silvin P Knight ◽

...

Keyword(s):

Physical Activity ◽

Prefrontal Cortex ◽

Longitudinal Study ◽

Anxiety Disorder ◽

Generalized Anxiety Disorder ◽

Resting State ◽

Short Form ◽

Saturation Index ◽

World Health ◽

Generalized Anxiety

Abstract Individuals with anxiety disorders exhibit lower intrinsic functional connectivity between prefrontal cortical areas and subcortical regions. The prefrontal cortex (PFC) is sensitive to the acute and chronic effects of physical activity (PA), while the anxiolytic effects of PA are well known. The current study examined the association of generalized anxiety disorder (GAD) and its interaction with PA, with resting-state, left PFC oxygenation. This cross-sectional study used data from participants (N = 2444) from The Irish Longitudinal Study on Ageing, a nationally representative prospective study of community-living adults aged 50 and older in Ireland. The Composite International Diagnostic Interview Short-Form determined fulfillment of criteria for GAD. The short-form International Physical Activity Questionnaire determined adherence to the World Health Organization PA guidelines. Resting-state, left PFC oxygenation was continuously measured via a Portalite. Tissue saturation index (TSI) was calculated as the ratio of oxygenated hemoglobin to total tissue hemoglobin (expressed as a percentage) for the final minute of a 5-minute supine-rest period. Multivariable linear regression quantified associations of GAD with TSI in the total population and population stratified by PA status. Participants with GAD had lower TSI (b = −1.416, p = .008) compared to those without GAD. However, this association was modified by PA. Among participants who met the PA guidelines, TSI did not differ according to GAD status (b = −0.800, p = .398). For participants who did not meet the guidelines, TSI was significantly lower among those with GAD (b = −1.758, p = .004). These findings suggest that PA may help to protect brain health among older adults with GAD.

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