Gorka, A. X., Torrisi, S., Shackman, A. J., Grillon, C. & Ernst, M. (in press). Intrinsic functional connectivity of the central nucleus of the amygdala and bed nucleus of the stria terminalis. Neuroimage.
The central nucleus of the amygdala (Ce) and bed nucleus of the stria terminalis (BST), two nuclei within the central extended amygdala, function as critical relays within the distributed neural networks that coordinate sensory, emotional, and cognitive responses to threat. These structures have overlapping anatomical projections to downstream targets that initiate defensive responses. Despite these commonalities, some researchers have proposed a functional dissociation between the Ce and BST, with the Ce promoting responses to discrete threat-related cues and the BST promoting responses to more diffuse kinds of threat. Intrinsic functional connectivity (iFC) provides a means to investigate the functional architecture of the brain, unbiased by task demands. Using ultra-high field neuroimaging (7-Tesla fMRI), which provides increased spatial resolution, this study compared the iFC networks of the Ce and BST in 27 healthy individuals. Both structures were coupled with areas of the medial prefrontal cortex, hippocampus, thalamus, and periaqueductal gray matter. Compared to the BST, the Ce was more strongly coupled with the insula and regions that support sensory processing, including the thalamus and fusiform gyrus. In contrast, the BST was more strongly coupled with regions involved in cognitive and motivational processes, including the dorsal paracingulate gyrus, posterior cingulate cortex, and striatum. Collectively, these findings suggest that responses to sensory stimulation are preferentially coordinated by the Ce, whereas cognitive and motivational responses are preferentially coordinated by the BST.