Serene Nuggets - Meditation and the brain

Meditation has been known to provide a multitude of benefits such as reduced stress and anxiety, improved concentration and memory, and improved sleep etc. By reducing mind wandering, which is the principal cause of increased stress in today’s world, meditation helps one to center and still the mind.

But can meditation really change the structure of our brain? Can it actually help improve our physical health? According to recent research in neuroscience, meditation indeed can alter the parts of our brain responsible for various cognitive functions such as memory, stress response etc. It also has tangible positive benefits for our cardiovascular system and improving our overall physical health.

A Primer On Neuroscience

Before diving into the various benefits of meditation, I’d like to take a short detour and explain the neuroscience behind how our mind works. Our brain is the most complex organ in the body, and controls everything from our thoughts, behaviors, actions to involuntary actions such as our heart rate, breathing and blood pressure.

The brain is composed of specialized cells called neurons. The human brain is supposed to contain approximately 100 billion neurons - research

Each neuron is connected to thousands of other neurons, which can lead to trillions of neural connections throughout our brain. The neurons communicate with each other via electrical impulses. To take an example, suppose you are reading a book. Your eyes would generate electrical impulses in response to the light which enables you to read. These electrical impulses would travel to your brain, and be received by the cerebral cortex which is responsible for functions like reading and comprehension. This part would then process the information and you are able to make sense of what you read.

These clusters of neurons are divided into various regions, each of which has a specific responsibility. Note that they don’t work in isolation, but with each other to coordinate our actions and responses.

2 of the major parts in our brain, which are affected by meditation are

Cerebral cortex - This forms the majority of the brain and is responsible for all of our conscious movements, thoughts, actions, reasoning and planning. As an example, when you reason about something you read, the prefrontal cortex which lies behind the forehead is active. The cerebral cortex has various parts, which are responsible for other actions such as vision, taste, smell, sight and touch. This article does an excellent job of breaking down various parts of the cerebral cortex and their functions.

The limbic system - This is responsible for a number of functions, such as memory formation and emotional regulation. Here are the important parts of the limbic system -

Hippocampus - The main purpose of the hippocampus is in storing memories. It is also responsible for transferring short term memories to long term memories which are stored in the cerebral cortex. It is also responsible for spatial navigation.

To put into context just how important the hippocampus is, it is the region which is affected by Alzhemers disease. We lose tissue in this region when affected by Alzheimers which leads to loss of memory - https://www.webmd.com/brain/hippocampus-what-to-know

Amygdala - The main purpose of the amygdala is processing of emotions, such as fear, stress and anger. It is also responsible for triggering the fight-or-flight response in the body in response to fear. Example, when you sense danger, it is the amygdala which triggers the body to run away and escape the dangerous situation.

It also has various other functions such as controlling your reaction to positive emotions (example parenting) and connects emotions to memories. So whenever you remember the smell of gingerbread your family cooks for christmas and feel happy, Amygdala is the one responsible - https://my.clevelandclinic.org/health/body/24894-amygdala

Neuroplasticity

Previously, it was thought that our brain structure is mostly fixed after birth and cannot be changed. Neuroplasticity refers to the brain’s ability to reorganize connections between neural networks, where connections between neurons which are frequently used can be made stronger, as well as severing unused connections - https://www.verywellmind.com/what-is-brain-plasticity-2794886

Neuroplasticity is a lifelong process, where our brains adapt to our life experiences. For example, learning a new skill such as the guitar can improve connections between neurons which are responsible for motor movement and coordination. Similarly, meditation has been known to change our brain structure. We will cover more of how meditation changes the brain in the articles to follow.

Let’s explore how meditation can help improve our brain structure.

Improved Memory, Concentration and attention

According to research conducted at the Center for Neural Science in New York University, meditation can help increase working memory, attention and reduce stress and anxiety. The research was a randomized trial conducted on subjects between the ages of 18-45, with a control group which was made to listen to podcasts versus the focus group who did a daily guided 13 min meditation session.

Another 2-week research which had participants undertake GRE reading comprehension tasks, showed that participants who did a 2 week mindfulness training, showed improved cognitive performance, as well as were less distracted during the GRE reading.

Meditation accomplishes this by increasing the grey matter density in the frontal cortex regions and hippocampus which are associated with tasks like concentration, focus, memory retention and planning.

Reduced stress and anxiety

Amygdala is an important part of the limbic system of the brain, and its major function is processing of emotions such as fear, stress and anger. It also activates the fight-or-flight response of our body. Refer https://www.simplypsychology.org/amygdala.html

For example, our ancestors in the past would flee when they saw a lion approaching them. This was crucial for their survival. Although today we do not have to fear a lion approaching us, the other stressors we face, such as a tight deadline at work, can seem as equally threatening and thus trigger this fight-or-flight response, which leads to increased anxiety.

In fact, constant exposure to such stresses can lead to increase in blood pressure, heart rate, and also release glucose into the blood to provide energy for the fight or flight response. This works when we’re actually in a dangerous situation, like our ancestors, but has debilitating effects on the body if not, for example, it can lead to increased risk of stroke, reducing our immunity and increased blood sugar. Furthermore, the more anxiety we are subjected to, the more intense is the response of the amygdala to this anxiety.

In a study done at Harvard Medical School, researchers used

functional magnetic resonance imaging (fMRI) scans to measure the activity of the brain while participants engaged in daily activities, before and after a 2 month meditation session.

It was found that after 2 months, there was a reduction in the activation of the amygdala when participants watched emotional content, which means meditation can actually lead to reduced stress.

Another way meditation helps us reduce our stress and anxiety is by calming down the autonomous nervous system.This leads to a decrease in blood pressure and heart rate. Furthermore, it has also shown to increase activity in the regions of the brain associated with controlling the autonomic nervous system and emotional regulation - https://www.headspace.com/meditation/anxiety

Reduce chronic pain

Chronic pain is a severe condition which affects nearly 100 million Americans each year. Mindfulness has been proven to benefit people suffering from chronic pain. https://www.mayoclinichealthsystem.org/hometown-health/speaking-of-health/use-mindfulness-to-cope-with-chronic-pain

Thalamus is the information relay center of the brain. It relays all information from our senses to the cerebral cortex for further processing - https://my.clevelandclinic.org/health/body/22652-thalamus

One study found that mindfulness meditation helps reduce chronic pain, by deactivation of the thalamus and thus inhibition of pain signals to the brain. There is a strong connection between the Thalamus and precuneus, which is involved when people engage in self reflection and aspects of consciousness.

Through mindfulness meditation, we learn to experience thoughts without reacting to them, which weakens this connection and thus helps alleviate pain - https://www.medicalnewstoday.com/articles/mindfulness-meditation-changes-how-the-brain-processes-and-perceives-pain#Pain-processing-and-self-reflection:-Whats-the-link?

Improved sleep

Although primarily treated via sleep medication and practices such as CBT-I (Cognitive behavioral therapy), mindfulness meditation has become popular in recent years for the treatment of sleep.

A study conducted among 83 students, showed that mindfulness meditation helped reduce rumination and overthinking, as well as reduced anxiety and increased positive mood states, all of which are extremely beneficial for improved sleep.

This is done by reducing activity in the default mode network, the brain region involved in rumination - https://stanfordmag.org/contents/what-happens-when-you-meditate

By honing our focus on the present moment and observing thoughts non-judgmentally, we learn to stop overthinking and evoke the relaxation response within our body, which further helps improve sleep - Harvard research

In addition to the neural pathways, meditation also helps reduce blood pressure, heart rate and stress hormones like cortisol in the body, which can further aid sleep - https://www.sleepfoundation.org/meditation-for-sleep

Increased Happiness

As we saw before, meditation can help reduce stress and anxiety, which leads to an increase in happiness. In addition, meditation has been scientifically proven to increase gray matter density in important areas associated with emotion regulation and happiness such as the prefrontal cortex - research as well as reduction in the size of the amygdala which controls our fear and stress response.

Meditation also helps increase the production of important neurotransmitters which are crucial to reducing stress - https://goforward.com/blog/mental-health/the-forward-guide-to-meditation-for-stress-management. Some of these are

GABA - Gamma-aminobutyric acid

Which is responsible for inhibiting neural activity in the brain and thus promotes feelings of calm and well being. Meditation increases blood flow to the prefrontal cortex which helps produce more GABA.

Serotonin - 5-hydroxytryptamine (5-HT),

Is a neurotransmitter which is responsible for carrying messages between the central nervous system in your brain and the peripheral nervous system throughout the body. It is responsible for several functions such as learning, memory, happiness and hunger. When we have more serotonin, we feel calmer, happier and more relaxed.

In contrast, reduced levels of serotonin lead to depression and anxiety. Having a regular meditation practice in place helps calm the nervous system and promote relaxation response, thus increasing serotonin.

Norepinephrine -

Known as the stress hormone, it plays a crucial role during the fight-and-flight response of the body. Some of its functions include increasing heart rate to pump more blood to our muscles, increasing the breathing rate, increasing arousal, attention and awareness, and constricting blood vessels to help maintain blood pressure in times of stress.

During meditation, we stimulate the parasympathetic nervous system, which is responsible for the rest and digest functions in the body. This leads to reduced production of Norepinephrine, and thus reduced stress.

Reduction in blood pressure

Blood pressure is the amount of resistance blood is facing when flowing through our arteries. A higher blood pressure indicates narrower arteries.

Meditation has been known to increase the amount of nitric oxide in the body - https://www.mainlinehealth.org/blog/meditation-for-high-blood-pressure#:~:text=How%20can%20meditation%20lower%20blood,when%20the%20heart%20is%20pumping.

Which can lead to widening of the arteries. This makes it easier for the blood to flow and thus reduces blood pressure.

This was further confirmed by a study done at Harvard.

Improved heart health

High levels of stress and anxiety can lead to the release of stress hormones such as norepinephrine, adrenaline and cortisol. This can lead to debilitating effects on the body, such as increase in blood cholesterol, triglycerides, blood sugar and increase in blood pressure - https://www.urmc.rochester.edu/encyclopedia/content.aspx?ContentTypeID=1&ContentID=2171#:~:text=Studies%20suggest%20that%20the%20high,plaque%20deposits%20in%20the%20arteries.

Meditation activates the parasympathetic nervous system, which controls the rest and digest functions of the body, in contrast to the fight-or-flight system of the body. This includes reducing the blood pressure, and stemming the release of stress hormones. This makes for a healthier heart, and thus a healthier you.

https://www.pennmedicine.org/updates/blogs/health-and-wellness/2020/april/3-ways-meditation-can-help-your-heart-body-and-mind

Needless to say, having a daily meditation practice can do wonders for your overall physical, mental and emotional well being and pay huge dividends for the years to come.