The amygdala can be divided into anatomically defined ventral (containing the basolateral complex) and dorsal (containing the central nucleus and sublenticular extended amygdala) subregions. A host of animal studies have evaluated the effects of stress and mineralocorticoid receptor expression specifically in the basolateral complex of the amygdala (19, 39). Our exploratory analyses of ventral and dorsal amygdala subregions (see the online data supplement) showed no evidence that either structure was specifically involved in the effects we found in our study. Rather, we found a general effect on activation extending across both the ventral and dorsal subregions. This may reflect a glutamatergic drive of ventral neurons on dorsal neurons, resulting in the generally increased activity seen in the BOLD fMRI signal from the entire amygdala. Additionally, the trend-level effect in the right dorsal but not ventral amygdala may reflect the specific connections between the nuclei of the dorsal subregion (e.g., the central nucleus) and HPA axis targets (e.g., the paraventricular nucleus), which would be particularly influenced by differences in mineralocorticoid receptor signaling.
