There are two functional parts of the brain that play a key role in stress. These serve the functions of emotion and cognitive function. So I am calling them the 'emotional' brain (amygdala and its connections and medial forebrain structures including the medial prefrontal cortex) and the 'logical' brain (the dorsolateral prefrontal cortex, other parts of the prefrontal cortex, parts of the cingulate cortex and parts of the hippocampus).
Our emotional brain and our logical brain are engaged in a constant tug-of-war. The logical brain keeps the emotional brain in check. The emotional brain is constantly trying to break free from the logical brain's restraint. Normally, the tug-of-war is so well balanced that no one wins. The minute something makes one side stronger, even for a moment, the balance is tipped. Stress is an example.
Our emotional brain is constantly scanning our environment for threats. It is very trigger-happy. If it detects something threatening (such as someone's 'angry' facial expression), it presses the 'stress' button even before the rest of the brain has processed what is going on. This results in a 'fight or flight' reaction where your body tenses up and you are prepared for danger or conflict.
This 'tense' response momentarily strengthens the emotional brain, so it can stay on high alert for further threats. The emotional brain now overpowers its opponents. All the parts of your brain which normally oppose the emotional brain are overthrown.
Certain aspects of your brain are particularly affected. Your 'logical' brain is the first victim. This is why it is harder to concentrate and focus when you are under stress. New brain cells are being born and are growing all the time in certain sites within our brain, including in the logical brain. We can tell this is happening when we find the growth factor BDNF swimming around brain cells. This process of birth and growth of brain cells in the logical brain is also affected by stress. Over time, we might find levels of BDNF go down and this correlates with parts of the logical brain shrinking a little. We see this in victims of post-traumatic stress disorder. The opposite of the 'tense' signal that makes your body tense up, is a 'relaxation' signal that makes you relax again when you feel safe. This relaxation signal is also turned off by the emotional brain.
Repeated encounters with stress make the emotional brain grow stronger and stronger. You can tell this is happening as you start feeling more negative. Fearful and negative memories may fill your mind more and more and you may become more sensitive to negative things doing on around you. After a while, this can lead to anxiety, depression, chronic fatigue and burnout.
The good news is, there is an antidote.
Many approaches to stress usually target only one aspect of its effect and hence don't work. Instead, the best-formulated antidote is to specifically target each separate aspect of stress. If we enhance the logical brain, if we increase the birth and growth of brain cells in the logical brain and if we raise the relaxation signal all at the same time, we can push back against the force of the emotional brain from every angle and re-establish equilibrium.
It sounds extraordinary, but science shows it may be entirely possible to do this with diet, lifestyle and simple behavioural modifications. There is no need to make any drastic changes to your life or to take any drugs. It requires a little discipline ...but only a little!