For thousands of years, people have noticed the physical sensations and mental and emotional changes that come with anger. Thanks to fMRI and other brain-imaging technologies, we can now see which areas of the brain become active as emotions like anger build. In this article, we’ll explore the physiological journey that anger takes through the body and mind when we first sense a threat. As we go through this process, you’ll encounter some technical terms for neurotransmitters and brain regions. However, the most important idea is to understand the balance between the part of us that reacts emotionally and defensively to a threat, and the part that can pause to think and decide what, if any, protective action is needed.
Anger
Anger is a deep and visceral emotion that is often fed by sadness, fear, and shame. It is frequently accompanied by hostility and/or aggression.
Hostility implies the intent to harm. Very often, you will find yourself wanting to hurt back or take revenge to feel empowered rather than collapsing into shame or vulnerability.
What does anger look like in the brain?
The Amygdala
Two almond-shaped structures in our brains, called the amygdala, as the place where emotions begin. It is located in the back of the brain: that is, the “old” brain, present before modern human beings began serious development of their executive pre-frontal cortex in the front of the brain.
Amygdala: The Emotional Center
The first spark of anger activates in the amygdala before you are even aware of it. The amygdala turns on the stress response system in your brain and body, also known as the HPA axis.
The HPA axis consists of the:
- Hypothalamus
- Pituitary gland
- Adrenal glands (on top of the Kidneys)
Neuroscientists often refer to the amygdala—two small, almond-shaped structures deep in the brain—as the starting point of our emotions. Located in the older, more primitive part of the brain (toward the back), the amygdala evolved long before humans developed the advanced prefrontal cortex at the front of the brain. The main role of the amygdala is to detect potential threats to our safety and trigger an alarm response, pushing us to act for our protection. The challenge with managing anger is that the amygdala is wired to react instantly, often before the prefrontal cortex—the part responsible for reason, logic, and judgment—can fully assess the situation.
Getting Ready for Action
When anger arises, muscles throughout the body tense up. At the same time, neurotransmitters called catecholamines are released, providing a surge of energy that can last for several minutes.
We know that if an angry or stress response continues to occur in the body, we eventually end up with adrenal exhaustion.
The Prefrontal Cortex (PFC)
While there are certainly moments when we need to react instantly to real danger—like dodging a speeding car or catching a child before they fall into a stream—most modern threats are psychological rather than physical. For example, we might feel threatened when unfairly criticised by a partner, receive an unexpected and unjust bill, or see an award go to someone whose work we believe is inferior to our own. In these situations, an immediate, emotional reaction from the amygdala isn’t usually helpful.
This is where the prefrontal cortex (PFC) comes in. The PFC is the area of the brain responsible for reason, logic, and thoughtful decision-making. It helps us pause, assess the situation, and choose a more measured response rather than simply reacting on impulse.
What are Catecholamines?
- Hormones: Adrenaline, noradrenaline, and dopamine are hormones that play a role in the body’s “fight-or-flight” response.
- Produced: They are primarily produced by the adrenal glands, located on top of the kidneys.
- Function: They help transmit nerve impulses, increase heart rate and blood pressure, and release glucose for energy in response to stress.
Catecholamines are hormones and neurotransmitters, like dopamine, norepinephrine, and epinephrine, that prepare the body for the “fight-or-flight” response to stress by increasing heart rate, blood pressure, and mental alertness. They are produced by nerve tissue and the adrenal glands and are crucial for stress response, nutrient metabolism, and the generation of body heat.
The Adrenal Glands
You have two adrenal glands, which are located on each side of your spine, just above your kidneys. Your adrenal glands are part of your endocrine system.
The endocrine system includes several glands that secrete hormones to regulate blood pressure, metabolism, blood sugar, reproduction, stress responses, immune responses, and many other essential functions.
Each adrenal gland has an outer adrenal cortex and an inner adrenal medulla, and these two regions secrete different hormones.
The adrenal glands are a key component of the specific system the body uses to respond to stress. The overall stress response system in your body is known as the hypothalamic-pituitary-adrenal (HPA) axis, and the HPA axis is a connection between your brain and your adrenal glands. The HPA axis is composed of the hypothalamus and pituitary in your brain and the adrenal glands.
The adrenal glands produce dozens of different hormones. Cortisol, DHEA, norepinephrine, and adrenaline are the main stress hormones secreted by the adrenal glands.
Cortisol – The Stress Hormone
Overall, cortisol helps maintain balance, or homeostasis, in your body during times of stress. Pain, low blood glucose levels, and intense exercise are all types of stress that could induce the release of extra cortisol.
Cortisol is a steroid hormone that is made by the adrenal glands. When stress occurs, the hypothalamus increases the production of corticotrophin-releasing hormone (CRH) to stimulate the release of adrenocorticotrophic hormone (ACTH) from the pituitary gland.
The ACTH then stimulates the release of cortisol from the adrenal glands. The subsequent increase in the cortisol level improves the ability to respond to stressors while maintaining balance or homeostasis, which is why it is known as the stress hormone.
Cortisol can also induce inflammatory effects at times. Research shows the initial low levels of cortisol during a stress response have an inflammatory effect, while the higher levels of cortisol that are associated with a more prolonged stress response are anti-inflammatory.
While cortisol is known as the stress hormone, it is crucial for the optimal function of the body every day. In healthy individuals, cortisol levels naturally shift throughout the day in a pattern known as a diurnal rhythm. A diurnal rhythm is a circadian rhythm that is repeated every 24 hours and synchronised with the day/night cycle. The presence of “stress” or certain medical conditions can affect cortisol levels and disrupt a healthy diurnal rhythm.
The way it works is the amygdala will send a signal to the hypothalamus. When the hypothalamus receives that signal, it will release a hormone called CRH (corticotropin-releasing hormone).
This hormone will signal to the pituitary gland to release ACTH (adrenocorticotropic hormone). ACTH reaches the adrenal glands, which in turn, will secrete stress hormones like cortisol, adrenaline, and noradrenaline.
Summary of the Neuroscience of Anger
When we perceive a threat, we begin to get angry, and neurotransmitters are released causing both physical and attentional changes to help prepare us to deal with the threat.
The amygdala in the older part of our brain is tasked with identifying threats to our wellbeing. It is the part that sounds the alarm when any perceived threats are identified, motivating us to take protective action.
The PFC is the executive (newer) part of the brain that enacts reasoned judgment, logic, and well-thought-out responses; its job is to rein in emotions originating in the amygdala in order to regulate us emotionally.
Recent research has used fMRI neuroimaging to empirically demonstrate that people use different parts of their brain to register anger (an amygdala function) than to regulate punishment-related behaviours (more of a PFC function).
References
Cashcoach.io. (2020). Image of amygdala and pre-frontal cortex. Novamoney.com Retrieved on 18 Novmber 2024, from: https://novamoney.com/images/uploads/4_brain.jpg
Gray, J. (2018). How anger affects your brain and body. Anger, nursing tips, health guide. Retrieved on 18 November, 2024, from: https://www.nicabm.com/sample/nicabm-infographic-anger/
Stosny, S. (n.d.). What happens to your body when you are angry (image). Microsoft Bing Images. Retrieved on 18/11/24, from: http://capacitybuildingdevelopment.blogspot.com/2016/06/anger-management-isnt-as-difficult-as.html
