Anxiety is a complex emotional response similar to fear, involving similar brain processes and causing comparable physiological and behavioural reactions. Both fear and anxiety originate in brain areas designed to help organisms deal with danger. Fear is typically linked to a clear, present threat, while anxiety occurs in the absence of immediate peril. When suffering from anxiety disorder, worry and fear are constant and overwhelming, greatly affecting life and potentially preventing the pursuit of goals and dreams.
The Role of the Amygdala
The amygdala, a small, almond-shaped structure located near the centre of the brain (there are actually two, one in each hemisphere), plays a significant role in the amygdala and anxiety. It is critical for generating the emotional and physiological response to stimuli and is involved in modulating the storing and subsequent retrieval of the narrative of events, as well as their autonomic and somatic components. The amygdala is part of the limbic system, which is the emotion centre of the brain. It functions as a built-in alarm system, constantly scanning experiences for any indication of danger. If it detects potential harm, it sets off the fear response, an alarm in the body that prepares for fight or flight. The amygdala is described as the root of fear.
The amygdala is involved in attaching emotional significance to situations or objects and forming emotional memories, which can be positive or negative. In the context of anxiety, it attaches anxiety to experiences and creates anxiety-producing memories. Emotional memories created by the amygdala are based on associations it experiences. The amygdala’s language is not one of words or thoughts but of emotions, focused narrowly on danger and safety. Association is an essential part of this language.
When an event is encoded as a traumatic memory, the amygdala generates a heightened awareness that produces chronic inescapable stress. This stress alters the brain and increases vulnerability. Genes can influence the sensitivity of the amygdala, making some individuals more vulnerable to developing fears and anxieties. Hardships early in life and current stresses can also lower the threshold for amygdala activation.
Even when the cortex is the source of anxious thinking, the amygdala causes the physical sensations of anxiety to occur. Experiences of fear, anxiety, or panic often arise due to the involvement of the amygdala.
Connections to Other Brain Regions and Their Roles
The amygdala receives input from a variety of brain regions and has output to many others.
- Thalamus: Threats enter the thalamus through our senses and are then transmitted to the amygdala. The lateral nucleus of the amygdala receives information directly from the thalamus, even before the cortex does.
- Cortex: The cerebral cortex is the thinking part of the brain. There are two fairly separate pathways in the brain that can create anxiety: one involves the cortex (perceptions and thoughts) and the other travels more directly through the amygdala. The cortex pathway is more conscious and involves sensations, thoughts, logic, imagination, intuition, conscious memory, and planning. The cortex can initiate or contribute to anxiety by activating the amygdala. The amygdala responds to information passed on from the cortex. Neuroscientists do not yet know exactly how the amygdala distinguishes whether the information it receives from the cortex is valid or based on an overactive imagination.
- Prefrontal Cortex/Frontal Lobes: Located just above the eyes, the frontal lobe has powerful bidirectional connections with other limbic nuclei, including the amygdala and the thalamus. The prefrontal cortex (part of the frontal lobe) is essentially an inhibitor of our limbic system and is involved in the evaluative aspects of a threat (threat vs. non-threat). The medial prefrontal cortex, located directly above the eyes, acts like a watchtower, offering a view from on high to assess if a perceived threat is real or a false alarm. However, when the stress response is triggered, the emotional brain (including the amygdala) can overwhelm or ‘hijack’ the prefrontal cortex, inhibiting clear and rational thinking. If you are not too upset, your frontal lobes can help restore balance by helping you recognise a false alarm and stop the stress response. People who experience high levels of anxiety often have weaker connections from the cortex to the amygdala.
- Right Hemisphere (of the cortex): This hemisphere is strongly connected to anxiety symptoms, particularly intense fear and arousal. When the right hemisphere creates frightening images, the amygdala can become highly activated.
- Hypothalamus: The amygdala sends signals to the hypothalamus, where the physiological response to a threat is generated. The hypothalamus is a peanut-sized region controlling bodily processes like metabolism, hunger, and sleep. It is also involved in the fear response, alongside the amygdala, sympathetic nervous system, and adrenal-cortical system.
- Central Nucleus (of the amygdala): This is the portion of the amygdala where the fight, flight, or freeze response is initiated. It is like an ignition switch. When it receives a signal indicating danger, it activates the stress response by sending messages to many other brain parts, including the hypothalamus. When it produces a strong fight, flight, or freeze response, the ability to use the cortex to think is often limited.
- Lateral Nucleus (of the amygdala): This part receives incoming messages from the senses and constantly scans experiences for danger. It is the decision-making portion, determining whether the central nucleus should react. It forms emotional memories through association.
- Sympathetic Nervous System (SNS): The central nucleus has close connections to the SNS. The SNS is made of neurons connecting to nearly every organ system, creating the fight-or-flight response. Amygdala activation strongly energises the SNS, causing rapid physiological changes like increased heart rate and muscle tension.
- Parasympathetic Nervous System (PNS): The PNS balances the SNS, allowing for ‘rest and digest’. Stimulating the vagus nerve is one way to stimulate the PNS and calm the amygdala. Relaxation strategies can turn off the sympathetic nervous system and activate the parasympathetic nervous system.
- Cingulate Gyrus: Connects to the amygdala and regulates emotional reactions to pain and aggressive behaviour.
- Hippocampus: Involved in learning, memory, emotional control, and stress arousal. Prolonged exposure to stress can deteriorate the hippocampus. It also receives input from the amygdala as part of the fight, flight, or freeze response activation. Mindfulness practice has been shown to increase grey matter in the hippocampus, helping it better withstand stress and reduce anxiety.
- Vagus Nerve: A critical function is gathering information from major organs and sending it to the brain, essentially providing a livestream of the body’s state. It is the principal manager of the parasympathetic nervous system, functioning to calm the amygdala down and move you out of fight, flight, freeze, or fawn mode.
Anxiety as a Habit Loop
Anxiety can be understood as a habit loop. While anxiety is born from fear, it needs nourishment to grow. Understanding how habits are set up can help understand how the mind works in the context of anxiety.
Calming the Amygdala and Rewiring the Brain
Even though aspects of anxiety are beyond conscious control, anxiety does not have to control your life. Understanding how anxiety is created in the amygdala and how the cortex contributes helps one understand that anxiety is not completely within conscious control. The neuroplasticity of the brain opens the door to rewiring the brain to alter the experience of anxiety. Strategies targeting the amygdala are more direct and effective in easing anxiety, especially when the amygdala has initiated the response. The amygdala is constantly learning and changing based on day-to-day experiences. To exercise control over the amygdala, one needs to communicate new information using its own language, which is based on experience and associations. The amygdala learns from its experiences, and one can use the language of associations to make new connections.
To change amygdala-based anxiety, there is only one sure way for the amygdala to learn: experience. Exposing the amygdala to situations that contradict the association between a trigger and a negative event allows it to develop new connections that compete with those leading to fear and anxiety. This is similar to creating a new neural path that acts as a bypass. New learning in the amygdala occurs in the lateral nucleus. Practicing exposure techniques communicates new information to the lateral nucleus and rewires pathways associated with specific triggers.
Here are some tools and techniques that can help calm the amygdala and rewire the brain:
- Self-talk strategies: Imagery or internal dialogue can be activated to address the neocortex, which can override amygdala responses and bring the amygdala into a more tolerable level of arousal.
- Deep Breathing Techniques: Breathing quickly and shallowly when anxious can lead to hyperventilation, which the amygdala detects instantly. Correcting this imbalance using deliberate breathing sends a signal to the amygdala to relax. Deep breathing is an effective amygdala-based coping strategy, even when the cortex is turned off during a panic attack. A breathing meditation practice involves focusing attention on the breath, observing the sensations of inhaling and exhaling. Slow, deep breaths help reduce amygdala activation.
- Relaxation Strategies: These practices are extremely valuable in reducing anxiety. There is no single right way to achieve the relaxation that reduces amygdala-based anxiety. Learning to slow breathing and relax muscles turns off the sympathetic nervous system and activates the parasympathetic nervous system.
- Physical Activity/Exercise: Exercise has powerful effects on the amygdala, potentially surpassing many antianxiety medications in effectiveness. Engaging in active rather than passive responding is necessary to overcome the inclination towards avoidance.
- Improving Sleep Patterns: Sleep has a strong impact on the amygdala’s functioning. Lack of sleep leads to heightened anxiety and makes the amygdala more reactive.
- Exposure Therapy: This powerful technique involves activating the amygdala in the presence of triggers to teach it through experience. It involves exposing the amygdala to triggers, often in a gradual manner using a hierarchy. The most important element is practice; the only way the amygdala learns is through experience.
- Imagery: Positive imagery from the right hemisphere can be used to combat anxiety. Visualisation can decrease sympathetic nervous system activation in just a few minutes. It is most effective at reducing amygdala activation if combined with muscle relaxation and slow, deep breathing. Positive emotional memories created by the amygdala usually don’t cause much difficulty.
- Meditation/Mindfulness: Various meditative practices, including mindfulness, have been shown to reduce amygdala activation. They affect processes in both the cortex and the amygdala. Meditation is an effective method for calming amygdala activation, particularly when the focus of attention is the breath. A regular practice can reduce stress-related difficulties and has direct and immediate calming effects on the amygdala, producing both short-term and long-term effects and increasing parasympathetic nervous system activation.
- Music: The melodic and emotional aspects of music, processed by the right hemisphere, can engage this hemisphere in positive emotions.
- Stimulating the Vagus Nerve: The vagus nerve manages the parasympathetic nervous system, which calms the amygdala. Stimulating it is one way to stop the amygdala from sending more stress signals. There are tools that can be used to stimulate the vagus nerve.
- CPR for the Amygdala: This practice uses breathwork as a form of distraction to soothe the amygdala. It involves checking in with oneself, acknowledging feelings, getting curious about thoughts and feelings, validating how the amygdala was trying to protect you, and choosing self-care to soothe the amygdala.
- Havening Therapy: The amygdala and limbic system are discussed in a primer on Havening, focusing on brain anatomy and the encoding of traumatic memory. While the specific techniques are not detailed, Havening is presented in the context of understanding these brain structures and their role in stress and traumatic memory.
The recommended approach to begin rewiring the brain to reduce anxiety is to first focus on calming the amygdala using relaxation, sleep, and exercise to reduce sympathetic nervous system activation. Then, identify triggers interfering with life goals and use exposure exercises to modify the amygdala’s response. Practice is essential, as the amygdala learns through experience; some anxiety during exposure is necessary for new connections to form.