Meditation and the Amygdala: Mediating Emotions in the Brain

Meditation and the amygdala

How does meditation affect the amygdala? Much has been written about meditation and the amygdala, but almost all of it was written from the perspective of 20th century understanding of the brain. The advent of the 21st century has been accompanied by a new understanding of how the brain works and how emotions are caused, experienced, and expressed.

The neuroscience of emotion was completely rewritten by Lisa Feldman Barrett starting 20 years ago, and its implications are only slowly filtering out to other fields. In this article, we will explore the effect of meditation on the amygdala and on emotions.

The Old View of the Amygdala

Before the great imaging advances of the 21st century, figuring out what the soft bits in the brain do was not just difficult; it was often misleading. The primary method of finding out what any part of the brain does was for (typically) a psychiatrist to treat someone with a brain lesion. The lesion might be obvious, like a physical trauma to the skull, or it might be subtle, identified by x-rays or postmortem analysis.

The psychiatric literature is full of studies of various types of lesions, symptoms, and behaviors. One of the most apparent correlations was that injury to the amygdala often resulted in either abnormally heightened or abnormally lessened fear responses in patients. Connecting these important changes in behavior to such lesions resulted in the amygdala being assigned the designation as “the fear center” of the brain. This reputation as “the fear center” is undeserved.

The amygdala’s reputation as the “fear center” is undeserved.

In the 1980s and 1990s, as we developed rudimentary methods of measuring the size of the amygdala, many studies were performed trying to find:

  • What variations exist in the size of the amygdala between individuals?
  • What variations in amygdala size affect behavior and health?
  • Specifically, what is the correlation of amygdala size and fear responses and behaviors?

These include studies that correlated amygdala size with fear.

Notable among the studies were tests on the amygdalae of meditators and the effects of meditating. The amygdalae of meditators were generally smaller, and the effect of extensive meditation tended to reduce amygdala size. The amygdala seemed to be connected with fear, so “smaller is better,” as the thinking went.

The New View of the Amygdala

The advent of fMRI just before the turn of the century changed much of what we know about how the brain works. fMRI stands for functional Magnetic Resonance Imaging. MRI had existed since 1971, but during the 90s it was extended (fMRI) to image blood flow, which allowed the operation of brain regions to be inferred and changes measured in living beings.

The short story of what we learned from fMRI is that the amygdala works with the other parts of the limbic system, the prefrontal cortex and hippocampus, to direct the brain in a whole new way than had been previously understood.

Among the roles the amygdala has is as the first responder when we are surprised. This is similar to the old view of the amygdala’s role, but it encompasses all kinds of surprise, primarily found by the thalamus, but also by other parts of the sensory cortex and all of the autonomic nervous system. I’ll say more about what surprise is in this context later.

Many of the amygdala’s roles involve constructing a model of the world our body inhabits and how our body might need to respond to that world.

The amygdala isn’t the enemy. It is an important ally in our ongoing struggle to survive in a sometimes hostile world.

Meditation and the Amygdala: How Emotions Work

You can read about this new understanding of how emotions work in Lisa Feldman Barrett’s book How Emotions are Made: The Secret Life of the Brain. Her view has been completely adopted by the neuroscience community. She is the Distinguished Professor of psychology at Northeastern University and is on the neurology faculty at Harvard Medical School. Her TED talk is a classic.

The explanation is complex, as it must be do cover emotions, but I will give a short version.

What we colloquially call emotions are really two things: affect and emotional behavior.  

  1. Affect is all the bodily functions that are managed by the autonomic nervous system: heart rate, breathing rate, blood pressure, hormone levels, sweating, mucous, crying, bladder, the digestive system, and dozens of other subsystems.
  2. Emotional Behavior is how we behave in response to affect. It is often what we think of as emotion, because it is what others see.

Dr. Barrett’s first finding is that affect results from our DNA; we are built to have affective responses to various stimuli, and all of us have just about the same ones. Her second finding is that emotional behavior is learned. It’s a consequence of DNA; it’s also a consequence of how we learned to cope with the world as we grew up. So emotions have an inherent and a learned component.

Emotions are both inherent and learned.

We Constantly Predict What Will Happen in our Lives

Dr. Barrett’s work is based on a new understanding of how the brain works, often referred to as predictive processing. This new understanding has been pioneered by Karl Friston, who is also the most influential contributor to fMRI technology, allowing him to become the most cited neuroscientist of all time.

This new way of thinking about the brain recognizes that it is separated from the world by a skull and dozens to hundreds of milliseconds of delay in sensory and motor processing, yet we have to survive in a world that is happening in real time.

The predictive brain deals with those delays by predicting what will happen and believing that those predictions are real. The limbic system does the predicting, and one of the primary contributors to the predictions is the amygdala. We act on the predictions, not the sensory input.

Like any good scientist, the brain tests whether input from our senses matches the predictions. When the predictions match reality, we are operating in real time. When they don’t, we are surprised.

This testing for reality is done in the thalamus, and when the thalamus finds a missed prediction, it reports surprise to the amygdala. Much of what the amygdala does in the face of surprise is hard wired, including most notably starting the release of stress hormones such as cortisol and adrenaline to prepare the body to respond.

Much of what the amygdala does in the face of surprise is hard wired, including starting the release of stress hormones.

What Understanding Emotions Means for the Amygdala

So far the new view of the brain attributed two functions to the amygdala: predicting what will happen in the world and responding with affective behaviors to surprises when the senses find its predictions are wrong.

The third function of the amygdala is to recall and act on memories to generate survival behaviors in response to the surprise. It can draw on three types of memories.

  1. Some memories it holds within itself. Such a memory can be acted on immediately, but the behavior will be simple and reflexive.
  2. Some memories it holds in common with the prefrontal cortex and hippocampus. Such memories are slower and less reflexive, but they may not be appropriate.
  3. Some memories are held primarily in the hippocampus and its adjoining cerebral cortex areas. These memories we can often choose and decide upon.

These three functions of the amygdala put it right in the middle of our emotional life. The amygdala is the center of our emotions.

The amygdala is the center of our emotions.

The Three Types of Memories: Understanding Emotional Behavior

One of the most important implications of Dr. Feldman’s work is that our emotional behavior is learned. That means it can be unlearned and relearned, but neither is easy. Various therapies have been found to modify memories of the third type.

The bad news is that the first two types of memory in the list above are very hard to modify. They involve direct neural connections, not different from how reflexes work. Studies have found that the second type of memory can involve myelinated neural connections between the amygdala and prefrontal cortex. Myelinated connections are faster to make lightning reactions, and they are harder to modify.

The good news is that most of our emotional behaviors are mediated by the hippocampus, where normal learning can result in relearning and change in our behaviors.

That leaves the first two types of behavioral memory. The brain only makes such memories in the case of severe early trauma and neglect. They form as last ditch attempts to survive an unsurvivable world.

Meditation and the Amygdala: Neuroplasticity

Neuroplasticity is a fancy word for relearning. It is used because it steps beyond the relearning that comes from rereading a book. It often involves unlearning and then relearning. Sometimes the unlearning comes from trauma, as when trauma or blood vessel breakage kills neurons, but there are other types of unlearning.

The first step in neuroplasticity is understanding that the brain and mind can change.

The first step in neuroplasticity is the understanding that the brain and mind can change. Anything that is based on memory can change, and Dr. Barrett’s gift to us is an understanding that our emotional behavior is one of those things. Many people go through life thinking they will forever be ruled by behaviors they never wanted.

Meditation can aid neuroplasticity. It can help us work with all three types of memory.

The challenge is how can we change our memories so that we can behave more successfully in today’s world. Most of our emotional memories were formed when they provided survival value in difficult periods, usually during childhood. We seldom know how they formed, much less how they can be reformed.

Meditation can help us reform memories. Its primary contribution is to help us let go of memories that are no longer serving us. It can help us deal with all three types of memory, although the first two are the hardest and will take the longest.

How Meditation Works with Memories

Neuroscience has found that when a memory is recalled, it is vulnerable to change. The catch is that intentionally recalling or interacting with a memory can reinforce it, making it more likely to be recalled and harder to let go of.

Meditation is a learned skill of gently allowing thoughts, which are memories, to arise in a cradle of loving kindness.

Note the keywords “skill”, “gently”, “allowing”, “loving”, and “kindness”. Meditation is an opportunity to make our memories vulnerable. We practice it so it becomes a skill. We practice being gentle with ourselves and our thoughts. We allow whatever arises. And we love what arises and treat it with kindness.

Meditation is a recipe for changing our minds. Once a memory is vulnerable in the light of the sun, it becomes a bit weaker. Repetition can continue the thought’s weakening. Any form of self aggression can rein in that progress.

Many people are frustrated by how long it can take to weaken our thoughts and memories. I can only suggest that the time be compared to how long we spent learning them when we were younger.

Meditation and the Amygdala: Mediating Emotions with Meditation

How can we tell we are making progress with our emotions? Sometimes we get feedback from those around us: family, friends, sangha members, co-workers, etc. When that is not available or not appropriate, we can look inside ourselves.

Ask yourself if you are being gentle with your thoughts. While that is part of the instruction for meditation, it is also a measure of progress. If you can’t be gentle with your thoughts, you are unlikely to be gentle with others, and if you are being gentle with your thoughts, the gentleness can’t help being seen in your emotional behavior.

The Amygdala and Meditation: How Important is the Amygdala to our Emotions?

From the viewpoint of our mind, the amygdala just a small piece of the puzzle.

From the viewpoint of neuroscience, the amygdala is very important. From the viewpoint of our mind, it is just a small piece of the puzzle. While calming or even shrinking the amygdala may be useful, gathering the courage and resolve to meditate is a much bigger issue in our overall mental health.

This article is part of the Community Blog, which offers reflections by Shambhala community members on their individual journeys in meditation and spirituality.

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2024-05-25 11:05:52