A lot of things can cause stress in everyday life: work, uni, family, lack of sleep… I feel like there’s a constant comparison of stress in society nowadays. “I’m so stressed,” “yes but at least you don’t have… going on” etc. Isn’t that just the worst? Or when people think current stress and problems are nothing compared to what they experienced in their day? Some of those amongst us who may even suffer from mental health illnesses may have heard “it’s all in your head!” Because of this, I thought I’d look at what actually happens in the brain to produce stress and anxiety and prove that being stressed and anxious, is just as physically as a more visible illness.
I hope you find this informative and feel free to rub this in the faces of somebody next time they doubt you!
The Frugal Frenchie
Firstly, it might be useful to talk about certain areas for clarification.
- Hypothalamus: this area, despite being small compared to other brain parts, is actually responsible for a lot of functions and processes. For example, it has a role in hormone release, expression of aggression, control of food intake and of course, stress.
- Pituitary gland: it’s linked to the nervous system by the hypothalamus
- Hippocampus: like the amygdala and the hypothalamus, it is part of the limbic system. Like all brain areas, it is involved in many processes in the body, but especially long-term memory, spatial navigation and a “mediator” in stress responses
- Amygdala: the amygdala is another part of the limbic system, traditionally known for its role in the fear response (flight/fight/freeze) and negative emotions
Stress, in general, leads to the release of corticotrophin-release hormone (CRH) in the hypothalamus. As the pituitary gland is linked to the hypothalamus, it releases adrenocorticotropic hormone (ACCH). Being very brief, this leads to the adrenal gland releasing cortical (the hormone that gets all the praise for stress).
This, after all that jargon, is the important part. Cortisol leads to increased sympathetic activation which is basically the activation of the sympathetic nervous system (SNS) that is responsible for all these physiological bodily responses like fight/flight/freeze, increased heart rate, sweating and so on.
The amount of cortisol that gets released is what affects how much/or little we react to feelings of stress. Why some people may just sweat a little, or others may have a panic attack or freeze. The amount of cortisol produced depends on the activity of the amygdala and the hippocampus.
The amygdala is critical for fear response. Sensory information from the thalamus and cortex are processed in the basolateral nucleus of the amygdala and is passed onto the central nucleus. This activates the HPA-axis (which is a more formal term for stress response and its effects, including cortisol release).
The role of the hippocampus in this HPA-axis is actually that it measures cortisol levels. It’s the glucocorticoid receptors in the hippocampus that do this. When the cortisol levels are too high, the hippocampus inhibits the CRH release in the hypothalamus (if you remember from the first step) and this in turn stops the HPA-axis activation. It may not seem important, but without this, our body would not behave differently to whether we were being chased by a dangerous animal or if somebody made us jump by shouting “boo.”
Now why is this all important to know? Well, not only is it good head knowledge, but it’s to prove that our behaviour and feelings aren’t a part of our thoughts, but several processes and chemical releases in the brain. It’s important to know that this is normal, and we shouldn’t be made to feel guilty about it.
In those who have diagnosed anxiety or phobias, this happens as there is an overacitvation of the amygala, which means that their fear responses are a lot more powerful.
I hope you found this post interesting and if you learnt something new today, or enjoyed this post, please leave a comment below.