A failed top-down control from the prefrontal cortex to the amygdala in generalized anxiety disorder: Evidence from resting-state fMRI with Granger causality analysis

• DOI: 10.1016/j.neulet.2019.134314
• Publication Date: 2019-06-01T14:27:59Z
• Authors: Mengshi Dong; Likun Xia; Min Lu; Chao Li; Ke Xu; Lina Zhang
• Keywords: Ventromedial prefrontal cortex; Superior frontal gyrus; Ventrolateral prefrontal cortex; Middle frontal gyrus

AbstractObjectiveIn generalized anxiety disorder (GAD), abnormal top-down control from prefrontal cortex (PFC) to amygdala is a widely accepted hypothesis through which “emotional dysregulation model” may be explained. However, whether and how the PFC directly exerted abnormal top-down control on amygdala remained largely unknown. We aim to investigate the amygdala-based effective connectivity by using Granger causality analysis (GCA).MethodsThirty-five drug-naive patients with GAD and thirty-six healthy controls (HC) underwent resting-state functional MR imaging. We used seed-based Granger causality analysis to examine the effective connectivity between the bilateral amygdala and the whole brain. The amygdala-based effective connectivity was compared between the two groups.ResultsIn HC, the left middle frontal gyrus exerted inhibitory influence on the right amygdala, while in GAD group, this influence was disrupted (single voxel P < 0.001, Gaussian random field corrected with P < 0.01).ConclusionOur finding might provide new insight into the “insufficient top-down control” hypothesis in GAD.