Altered Task-Evoked Corticolimbic Responsivity in Generalized Anxiety Disorder

Abstract

Generalized anxiety disorder (GAD) is marked by uncontrollable, persistent worry and exaggerated response to uncertainty. Here, we review and summarize the findings from the GAD literature that employs functional neuroimaging methods. In particular, the present review focuses on task-based blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI) studies. We find that select brain regions often regarded as a part of a corticolimbic circuit (e.g., amygdala, anterior cingulate cortex, prefrontal cortex) are consistently targeted for a priori hypothesis-driven analyses, which, in turn, shows varying degrees of abnormal BOLD responsivity in GAD. Data-driven whole-brain analyses show the insula and the hippocampus, among other regions, to be affected by GAD, depending on the task used in each individual study. Overall, while the heterogeneity of the tasks and sample size limits the generalizability of the findings thus far, some promising convergence can be observed in the form of the altered BOLD responsivity of the corticolimbic circuitry in GAD.

Keywords: amygdala; corticolimbic circuit; fMRI; generalized anxiety disorder; prefrontal cortex.

Figure 1

Summary of the findings from task-based fMRI studies of generalized anxiety disorder (GAD), focusing on blood oxygen level-dependent (BOLD) signal changes within the corticolimbic circuit and other brain regions. Overall, the results were largely dependent upon the task used to elicit regional brain activity. ACC: anterior cingulate cortex; AMY: amygdala; dmPFC: dorsomedial prefrontal cortex; HIP: hippocampus; INS: insula; vmPFC: ventromedial prefrontal cortex.