Stress and the hippocampus
The hippocampus is the part of the brain that controls your mood, memory, concentration and knowledge acquisition. In general, the hippocampus contributes to how you adapt to your environment. People who suffer from depression see their hippocampus volume decrease and it seems that the longer these episodes of stress last, the smaller the hippocampus becomes. Narrative memory disorders often occur in people who suffer from depression.
Stress and the prefrontal cortex
While the hippocampus is often described as the area that controls your emotions, the prefrontal cortex is also involved in your ability to adapt. It is the area of the brain where your intelligence lies, but also the area that regulates your self-control and initiative.
People who suffer from chronic stress experience a decrease in the volume of grey matter, which is found in particular in the prefrontal cortex and several brain imaging studies have demonstrated these changes in the prefrontal cortex. A decrease in blood flow and glucose metabolism in the prefrontal cortex has also been observed and this can cause individuals to be unable to control their emotions, make decisions and adapt their behaviour and attitudes.
Stress and the amygdala
Located near the hippocampus, the amygdala is an essential part of the brain. Its main function is to manage emotions, including your reactions to fear and anxiety which are the most primitive emotions. During periods of depression and stress, the amygdala’s functions are affected. Unlike the hippocampus and the prefrontal cortex, the amygdala increases significantly in volume. This change has considerable consequences for the individual such as irritability, hyper-vigilance, anxious agitation as well as frequently over-reacting.
The consequences of stress on the brain
Several structural, functional and cellular changes are observed in people who are depressed including changes to the hippocampus, the prefrontal cortex and amygdala. All three of these areas regulate the way we manage our mood and emotions so the more intense and frequently we experience stress, the more severe the impact on the brain will be.