Article 7: Amygdala: Your Brain’s Alarm System

The amygdala is a small, almond-shaped cluster located in the limbic system. It’s often referred to as the brain’s "alarm system," "smoke detector," or “fear centre”—all for good reason. It plays a key role in detecting danger and triggering the body’s stress response, acting like the brain’s heater by turning up the intensity when it senses potential threats. But how does this process unfold, and why can it sometimes lead to overreactions?

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From Senses to Survival: The Thalamus and Amygdala

All sensory information—what we see, hear, and feel—first passes through the thalamus, the brain’s relay station (except for smell, which is directly linked to the amygdala—the reason for this is nothing can be more emotionally powerful than a smell). The thalamus receives sensory information and quickly shares it with different brain areas, allowing us to process it and decide what to do. It shares this information through two pathways:

1. Fast, short path to the amygdala (it receives the information first).
2. Slow, long path to the cortex (the thinking part of the brain).

Since the amygdala receives information before the cortex (traveling a shorter distance and double the speed), it can respond more quickly.

Why does the amygdala process information before the thinking brain? For survival.

Our brain is wired this way because, in dangerous situations, we don’t want to spend time analysing before we react. The thalamus sends information directly to the amygdala for fast processing, so we can act quickly and stay safe. This all happens outside of conscious awareness.

Amygdala and Hippocampus: Decoding the Threat

Keep in mind that the amygdala doesn't think or store explicit memory. Instead, it's involved in implicit memory - those preverbal experiences that are outside of conscious awareness. For example, as an adult, you won't consciously remember memories from infancy (under 3 years old), when the hippocampus is fully developed. However, unconsciously, in your body (and amygdala), you might. This can help to explain why someone who has experienced preverbal trauma might get triggered by certain things, and not know why. They might feel crazy, but they're not. This highlights the crucial importance of somatic, body-based treatments.

Back to explicit memory: Each time you see your dog, your amygdala doesn't 'know' it's your dog, even if the dog has been part of your life for 10 years. It never learns or remembers if it's dangerous or not. So how does it know when to ring the alarm bell? Well...

After receiving sensory input from the thalamus (or directly from smell), the amygdala consults with the hippocampus, which stores memories of past experiences. The hippocampus helps determine whether the perceived threat is real or not, guiding the amygdala in deciding whether to activate the stress response. For example, the hippocampus might 'remind' the amygdala that what looks like a snake is actually just a stick, or that the dog is your 'best mate' Scotty, allowing the amygdala stay calm.

As we discussed in our previous article (Article 6), chronic stress can impair the hippocampus, making it harder to assess situations accurately. This can lead the amygdala to misfire, reacting to safe situations with unnecessary fear—like in performance anxiety.

This highlights that it’s the perception of threat that matters. Even worried thoughts about the future can set off the amygdala. For example, an athlete might feel anxious before an important match and perceive it as a threat with thoughts like “I can’t do this,” “I’m not prepared,” or “What if I fail?” This sets off the amygdala’s alarm, activating the stress response and revving up the body as if facing a wild animal, rather than preparing to showcase skills and talent.

?The Double-Edged Sword of the Amygdala

The amygdala’s ability to detect danger is essential for survival, but it can become a double-edged sword when overactive. In people with chronic stress or trauma, the amygdala remains on high alert, causing constant anxiety and hypervigilance. This heightened sensitivity can lead to overreactions in everyday situations, making it feel like the alarm is always ringing, even when there’s no real danger.

?The Stress Response: Two Key Processes

When the amygdala senses a threat, it initiates two key processes:

1. Activating the Hypothalamus: The amygdala signals the hypothalamus to kickstart the body’s stress response by activating the Hypothalamus-Pituitary-Adrenal (HPA) axis. This increases heart rate, muscle tension, and redirects blood flow to prepare for fight, flight, or freeze.
2. Suppressing the Prefrontal Cortex (PFC): At the same time, the amygdala suppresses the prefrontal cortex, the part of the brain responsible for logical thinking. This makes it hard to think clearly in stressful situations—adaptive when faced with danger, but unhelpful during a presentation or exam, or when you want to perform at your best (e.g., the impact of performance anxiety). We go into more detail about the stress response in Article 8.

Chronic Stress: Why the Alarm Stays On

In individuals with complex trauma or long-term stress, the amygdala’s baseline is set higher, meaning it’s more easily triggered. The hippocampus, responsible for calming the amygdala (the brain's internal “air conditioner”), can also be damaged by ongoing stress, leading to memory problems and difficulty distinguishing real threats from perceived ones.

Brain Development and Pruning

During early childhood, the amygdala is highly active, which is why children often have intense emotional responses. As we grow and form secure attachments, the brain undergoes pruning, where unnecessary neurons in the amygdala are trimmed to help regulate emotions. In cases of trauma, this pruning process may be disrupted, leaving the amygdala hypersensitive to stress later in life.

Proper brain integration relies on the PFC regulating the amygdala, balancing emotional reactions with logical thought. In people experiencing complex trauma, there may be poor integration between the PFC and amygdala, making it harder for the PFC to keep the amygdala in check. Check out Article 14 for more information on pruning and secure attachment.

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Calming the Alarm: Techniques to Downregulate the Amygdala

Good news! The amygdala is a brain area we know we can change. The main issue with the amygdala (in terms of its dysfunction) is its often hyperactive - especially in trauma, anxiety, and addiction, and a little bit in depression. Ultimately, we want to learn to calm it down when it becomes overactive. This is where bottom-up techniques and social connection can be effective. Here’s how:

• Mindfulness-Based Exercises: help to shift the focus from- perceived threats to the present moment, gradually reducing the amygdala’s sensitivity. ?
• Grounding exercises: using the five senses is a great way to reconnect with the body and calm the stress response. Examples include progressive muscle relaxation, focusing on deep breathing. ?Slow deep breathing activates the vagus nerve, helping to calm the amygdala down, and re-regulating the body. ?Check out the article on grounding here.
• Movement and exercise: Physical activity helps release built-up tension and recalibrate the nervous system.

Social Connection: The Power of Social Medicine

Social connection is one of the most effective ways to regulate the amygdala. Positive interactions with others, including the therapeutic alliance, help to soothe the amygdala through co-regulation. This is known as "social medicine," and it’s especially important for emotional regulation and recovery from trauma. More on this in Article 13 (the power of connection).

The Adaptive Role of Stress: A Fine Balance

The amygdala’s role is essential for survival. However, when stress becomes chronic or trauma leaves lasting scars, the amygdala can misinterpret safe situations as dangerous. Learning to downregulate the amygdala through mindfulness, grounding, exercise, and social connection helps restore balance, ensuring the amygdala reacts appropriately without overwhelming us in everyday life.

Click HERE for Introduction article with list of topics.

#Neuroscience #Amygdala #StressResponse #TraumaRecovery #BrainIntegration #Mindfulness #SocialMedicine #PerformanceAnxiety

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