Amygdala Hijacking and Mitochondrial Biogenesis

Why do we sometimes say things we don't mean? And how can exercise improve our brain function?

Mar 18, 2024

Hey Brainiacs,

Welcome to this week’s newsletter! Let’s explore what happens to our brain when our emotions are running high, and how exercise can improve our brain health.

Amygdala Hijacking

I’m sure we can all remember those fights where our emotions got the best of us and we said some things we didn’t mean. We probably reacted in ways we’re not proud of. And our reaction was most definitely not proportional to the magnitude of the issue. It happens. But why? And how can we make it happen less?

This situation, where your emotions are running your brain and you’re not thinking rationally, has been termed the ‘amygdala hijack’ by Daniel Goleman in his 1995 book ‘Emotional Intelligence’. The amygdala is an area of the brain that plays a key role in interpreting and producing emotions. It stores our learned emotional responses to stimuli, both positive (‘happy’, ‘reward’) and negative (‘anger’, ‘stress’)¹. We know the amygdala does this from studies of people who have damage to their amygdala, who cannot process emotions from facial expressions, and who have trouble contributing rewards to actions¹.

However, the amygdala is also involved in threat assessment and initiation of the fight-or-flight response¹. And it cannot distinguish between a real physical threat and an emotional threat such as your boss yelling at you¹. Thus, intense and negative emotions, like stress or anger, will trigger the amygdala to initiate the fight-or-flight response. This causes the prefrontal cortex, which is in charge of complex decision-making, to slow down, and our rational mind is compromised. Thus, strong emotions activate the amygdala, causing reduced activity in the prefrontal cortex and less rational thoughts.

But it seems the story is not so simple. The story I’m telling you is based on our knowledge from 1995. We have done much research since then! We now know that the amygdala is involved in predicting future consequences and that we perform tasks best when the amygdala and prefrontal cortex work together². A recent study has shown that people with weaker prefrontal cortex-amygdala connections have higher levels of anxiety³. Therefore, it might be that the amygdala is not ‘hijacking’ the prefrontal cortex, but that the amygdala is not communicating properly with the prefrontal cortex^2,3.

Either way, we need some ways to handle this, both short-term and long-term!

Short-term solutions:

Take some deep breaths. We know that slow, deep breaths promote activity in the prefrontal cortex and reduce feelings of anxiety and anger⁴.
Remove yourself from the situation, if possible.
Use facts about the situation to talk yourself through it. Studies have shown that talking to ourselves about a situation in the third person can help us regulate our emotions⁵.

Long-term solutions:

Take actions to reduce your stress levels. We know that chronic stress changes how our amygdala functions⁶. Find time every day to relax.
Practice meditation and mindfulness. These practices reduce amygdala activity and strengthen the connections between your amygdala and prefrontal cortex⁷!

And if you want to learn even more about this process and ways to stop it, pre-order my book!

Mitochondrial Biogenesis

What and what? I hear you. Let’s break it down. Mitochondria are organelles in your cells. If you think of your cells as tiny human bodies, then mitochondria are an organ, like a lung. They serve a function to help your cells stay alive. You might have heard mitochondria referred to as ‘the powerhouse of the cell’, and this is because they produce energy. But they also store calcium, produce heat, and help decide which cells are no longer functioning and need to be removed. They’re very important! Now, biogenesis. Biogenesis means to create life from existing life. So mitochondrial biogenesis means increasing the number of mitochondria in a cell!

Mitochondrial biogenesis can be increased through exercise, and this helps improve cognitive function and mental well-being. Mitochondrial biogenesis was discovered by John Holloszy in the 1960s, in his studies looking at endurance exercise⁸. His original experiments demonstrated that long periods of endurance exercise caused mitochondrial biogenesis in muscle cells⁸. However, more recent experiments have shown that even a single bout of exercise causes a rapid increase of mitochondria in muscle cells⁸. This makes sense: your muscles need more energy to sustain that exercise. But what about your brain?

It has been shown in rodents that exercise also increases mitochondria in brain cells⁹! This experiment would be difficult to do in humans (you can’t just go and take their brains apparently, who knew?). But we do know from human studies that exercise improves cognitive functioning, overall well-being, and protects against neurodegeneration¹⁰. Thus, mitochondrial biogenesis in the brain may offer a plausible explanation as to how exercise provides all these brainy benefits.

Studies on neurodegeneration in humans¹¹ and rodents¹² also support this theory. Mitochondrial function is impaired in humans and rodents with various neurodegenerative conditions (Parkinson's and Alzheimer’s). However, even just moderate exercise (i.e. running on a treadmill) increased the lifespan of rodents and reduced markers of oxidative stress (which indicates poor mitochondrial functioning)¹³. Exercise improves the mitochondrial function in cells in your brain!

What I am trying to get at is exercise is good for your brain. And what I have tried to highlight is that even one session of moderate exercise is good for your brain. Exercise doesn’t need to be this scary and difficult thing. Moderate exercise will do your body and your brain lots of good!

Reminder: 6 weeks until Rewire launches, be one of the first to order! Pre-order: https://geni.us/1sWgaf6.

It would mean the world to me if you helped with the pre-order numbers and helped this baby get to the galaxy and beyond so that it can reach those who need it most.

Until next week,

Nicole x

P.S. Please leave comments with what topics you’d like to be covered in future weeks!

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