Brain functional abnormalities in the amygdala subregions is associated with anxious depression

Abstract Background Functional neuroimaging studies have provided strong support for the critical role the amygdala plays in emotional processing. The amygdala is composed of three primary distinct nuclei that have different functions in emotional regulation. Anxious depression (AD) was considered as a common dimensional symptom of Major Depressive Disorder (MDD). However, the neuroimaging basis of this special MDD subtype remains largely unknown. Therefore, it is necessary to study the functional connectivity of the amygdala's subregions in AD patients. Methods Eighty-three patients with AD, 70 non-anxious depression (NAD) patients, and 62 healthy controls were collected. Age and gender were well-matched. The functional connectivity of three amygdala subregions, including centromedial (CM), laterobasal (LB), and superficial (SF), were compared among the AD, NAD, and HC groups. The correlation between functional connectivity in the amygdala subregions and the HAMD factor scores were further analyzed. Results Patients with AD showed decreased functional connectivity between the right CM/LB and the right middle frontal gyrus relative to the NAD group. The NAD patients showed decreased functional connectivity between the right precentral gyrus and the right CM/SF compared to the HC group. The functional connectivity between the right CM and the right middle frontal gyrus was negatively correlated with the anxiety/somatization factor. Conclusion The functional connectivity between the right CM/LB and the right middle frontal gyrus might be the neurobiological mechanism of anxious depression. The FC between the right CM and the right middle frontal gyrus may help to explain the special clinical feature of the AD patients.