The Hippocampus
The hippocampus is responsible for three types of memory: episodic memory (events), semantic memory (facts from what’s read or heard), and spacial memory (location of things). In addition to keeping up memory and other maintenance functions, the hippocampus regulates cortisol levels.
During acute stress, the activation of the hippocampus by regulating the cortisol consolidates memory ,but during chronic stress, the glucocorticoid cascade hypothesis (figure to the left) occurs, whereby the hippocampus is damaged and shrinks. The shrinkage of the hippocampus causes damage to the body’s tissues and organs, memory problems, changes in the body associated with aging, and depression.
The Amydala
Stress induces the opposite effect of hippocampus on the amygdala. Rather than shrinking, the amygdala, the center for fear and aggression in the brain, increases in size. This accounts for the angry or anxious behavior of overly stressed people. The smaller hippocampus and bigger amygdala work together to create a free-floating type of anxiety.
