Neurobiology of Anxiety

Susan Stubbings

2 hours ago

6 min read

We all experience anxiety and fear at different points in our lives; these feelings are part of being human.

Yet in today’s fast-paced world, we have become human ‘doings’, leaving many of us overwhelmed, struggling with mental health problems, unable to manage daily tasks or enjoy life and are joyless.

Modern life offers technology, transport and household appliances designed to make life easier. Instead, these conveniences can add pressure: rather than using the time they save to do less, we often fill it by doing more.

Along with employment and financial uncertainty can heighten anxiety and overactivated the amygdala, the brain’s internal alarm system. Designed to detect and respond to threats, an overactive amygdala can create a negative feedback loop that sustains anxiety.

Below is the process of our Neurobiology of our nervous systems and how it affects us when it is on constant alert.

The Nervous System and Dysregulation

The nervous system has four key brain systems at play in dysregulation.

The Amygdala

HPA Axis

Prefrontal Cortex

Mirror Neurons

Process of Nervous System Activation

The amygdala is an almond shaped structure located near the top of the brainstem and plays a central role in regulating emotions. Often described as the nervous system’s “fire alarm,” it responds first when it senses a biological or emotional danger or a fear-related cue.

Internal or external cues can trigger trauma or anxiety-related responses: fight, flight, freeze, fawn, or collapse. These protective responses support our survival.

The Hypothalamic-Pituitary–Adrenal Axis often shortened to HPA Axis controls our stress hormones i.e. cortisol and adrenaline and fires within milliseconds of the Amygdala activation.

This system is in control of the sympathetic nervous system and regulating our stress responses, mood, digestion and immune functions, stores our energy and expenditure and releases epinephrine and norepinephrine, which results in the release of cortisol and adrenaline. This sets up a communication loop within, which is hormone based and utilising these hormones to transmit signals to the rest of our body.

When the nervous system is activated, it triggers stress responses. If this activation becomes frequent or persistent, it can disrupt cortisol levels and, over time, lead to burnout, physiological changes, and wear and tear on the body’s systems. These hormones enter the blood stream and cause the bodily sensations we feel when anxious such as increased heart rate, dry mouth or aches and pains from the flushing and surging hormone levels. Creating a negative feedback loop.

The Hippocampus a small but mighty part of our brain which supports memory and our sense of time, often referred to as our 'librarian'. Connected to the hypothalamus and amygdala, it links memories with emotions and helps regulate bodily functions, anxiety-related fight, flight, freeze, fawn, collapse responses, fear, and anger. As part of the limbic system, it also stores memories and helps us recognise and avoid danger.

The hippocampus has many receptors for cortisol it naturally helps shut down the increase signal and helps to return the body back to balance along with the parasympatheic nervous system.

Chronic stress through prolonged cortisol exposure can cause the hippocampus to shrink over time, setting up a self-reinforcing spiral, weakening the hippocampus ‘muscle’ also weakening the ‘brake’ to the release of cortisol in the prefrontal cortex. High cortisol levels damage the hippocampus, and this contributes to brain fog, feeling stuck, memory loss or brain freeze for example. Over the years, this may also be associated with conditions such as Alzheimer’s disease, dementia, epilepsy, PTSD and C-PTSD.

Selye’s proposed that it is the wear and tear of prolonged defence, not the stressors themselves which produces stress-related illnesses.

The hippocampus key role is memory and conceptualising events if it has reduced capacity it has difficulty in differentiating between then and now. This explains intrusive memories, flashbacks and difficulty switching off from the day.

The good news is we can strengthen and enlarge our hippocampus again, the brain also has something called 'Neuroplasticity' the ability to absorb information and enabling us to take on our daily challenges.

It makes sense then when we are trying to heal, regulate and manage our stress levels we work to stop the release of hormones so the hippocampus muscle can strengthen and regulate our system once again.

We are often looking for the big revelations to healing but it is in the simple every day activities which support our nervous system,

for example:

Brisk walking - uses accumulate excess energy from hormonal release
Aerobic exercise - uses accumulated excess energy from hormonal release
Learn all you can about the neurobiology of fear and anxiety - read this block until you understand the process it takes to become dysregulated - Knowledge is power.
Learn something new, a skill or a hobby - builds new connections in our synapsis
Take care of your basic needs sleep, eat healthily, exercise - offers room for meeting our more complex needs
Eat fish, blueberries and dark chocolate - to stimulate synaptogenesis i.e. new connections within the neurons which accumulate in the Hippocampus
Get off automatic pilot and switch thing up by doing something different in your daily routine, e.g. walk instead of take your car or bus
Learn mindfulness and meditation
Stress Management
Healing Trauma

The Prefrontal Cortex – our reasoning brain

The HPA axis quietly shuts down our prefrontal cortex within seconds of activation as the chemical flood our brains. The Prefrontal Cortex can be consider to be our 'brake system'.

When the sympathetic nervous system is activated due to the activation of the amygdala known as the ‘amygdala hijack’ our brakes don't work.

This hijack causing the prefrontal cortex to be unable to focus, concentrate or think logically and leads to swift fear-driven responses. We experience this as brain fog, numbing or muddled thinking. This significantly impacts our cognitive abilities including decision-making, emotional regulation and how we respond to and manage stress. This gives rise to the intrusive thoughts, flashbacks, nightmares, ruminations we experience and the repeated negative thought patterns.

Controlling our impulses, concentration and how we integrate and adapt to environmental changes including our inner environment. Since its main function is to integrate abstract, and future orientated thinking, this is cut off when we become dysregulated. Making it harder for us to find solutions in the here and now and manage our stress levels.

We can see from the above description the shutting down of our prefrontal cortex is a major problem for us for planning, impulse control, working memory and emotional regulation.

Our ‘brake system’ is shut down and this adds to the cycle of stress and fear the amygdala experiences and so the negative loop is created and anxiety and fear rule the systems and continues.

Mirror Neuron

Are our saving grace. They are specialised sensory motor brain cells which fire every time we perform an action or watch someone else perform the same action, this allows our brain to simulate others intention and movement.

The mirroring maps what we see onto our own motor systems and play a part in how we learn and recognise intutively, in short, mirror neurons operate out of conscious awareness implicitly on automatic.

The mirror neuron systems helps us to feel the feelings of others under heavy exposure and allows us to feel with others. When we are dysregulated this is much more difficult and we can end up feeling alone and lonely.

It makes sense then when we are dysregulated that we ‘need’ another regulated nervous system to help regulate our own, this is achieved through shared neural activations and feeds the empathic path.

Mirror neurons also feed into the social engagement system Dr Stephen Porges theory speaks about which is based within the Vagus Nerves neurophysiological network. The vagus Nerve bypasses the sympathic Nervous System and is connected to all our organs which give rise to the symptoms we feel. For example the need to urniate more, our digestion disrutptions and our palpitating heart.

Again simple exercies can strenghten the Vagus Nerve, for example:

Singing
Humming
Deep breathing
Cold exposure i.e. suck an ice cube or rub it on your wrists
Splash your face with cold water when you are activated
Visualization
Listen to calming music
Exercise - take a brisk walk
Hug someone or utilize the butterfly hug

We can begin to see how the nervous systems all fit together and works to either regulate or dysregulate our inner world. It makes sense then to engage with a therapist or a person whom you feel safe with to help to start regulating your nervous systems. You don't need to do anything in the beginning just be with others who are regulated and our mirror neurons will start to do their work just don’t be alone.

However, the person or people you engage with when you are dysregulated matter to your nervous systems so the mirror neurons can begin to get doing their work. We need 'another's regulated nervous system' to support ours until we can support ourselves.

This is one of the reason therapy makes sense when the therapist has done their own work, healed and can maintain a regulated nervous system so clients nervous systems can be support on all levels.