FIGURE 8.3
A Hormonal Feedback Loop This diagram simplifies a hormonal linkage, the HPA (hypothalamus–pituitary–adrenal) axis. Both the hippocampus and the amygdala stimulate the hypothalamus to produce CRH (corticotropin-releasing hormone), which in turn signals the pituitary gland to produce ACTH (adrenocorticotropic hormone). ACTH then triggers the production of CORT (glucocorticoids) by the adrenal cortex (the outer layers of the adrenal glands, atop the kidneys). Fear may either build or disappear, depending on other factors, including how the various parts of the brain interpret that first alert from the amygdala.