The hippocampus, amygdala and prefrontal cortex assists the brain in determining what is stressful and how to respond to the situation. The hippocampus not only stores memories and events but it also responds to the stress hormones in the blood. Mental disorders, like depression, may cause the neurons in the hippocampus to shrink, or weaken, starting a chain reaction to mental disorders. As the brain makes new neurons the repeated stress slows the production of those new neurons. Another key structure in emotional regulation is the prefrontal cortex. The prefrontal cortex is responsible for decision-making and memory but it can also shrink due to depression. Repeated stress may enlarge the amygdala and a hyperactive amygdala can lead to disrupted
