By Savannah Moscon & Emily Tufano

Meditation is an ancient technique that is gaining popularity due to its robust mental and physical health benefits. In fact, those in stressful situations or jobs (that’s us!) are encouraged to practice mindfulness through meditation to relieve chronic anxiety and stress. For many, the practice of mindfulness, defined as the process of attending to the present moment without judgment, can reduce ruminative thinking.¹ Additionally, meditation significantly increases quality of life by decreasing the symptoms of various disorders including anxiety, depression, and even chronic pain.² The utility and accessibility of meditation, makes this an attractive way to promote meaningful change in those who practice.

Interestingly, the effects of meditation seem to extend beyond personal development and may change the brain’s structure to further promote positive thinking and reduce stress. This is due to the brain’s inherent neuroplasticity; the brain can alter its architecture, connectivity, and resulting function at the cellular and behavioral level in response to internal and external stimuli.³ Life habits directly affect the structure and function of the brain, which is tightly connected to the risk of neurodegenerative disease and other disorders such as depression.³ In this article, we explore the evidence for meditation as a mechanism to reduce stress and promote long-term healing and disease prevention through altering brain structure.

How does meditation affect the structure of the brain?

Many recent findings have suggested that meditation alters the structure of various brain regions, particularly the hippocampus and prefrontal cortex (PFC), which we will discuss here.

The hippocampus is a brain region primarily responsible for learning, memory, regulation of hormone release, and importantly, emotional regulation.⁴ Activation in the hippocampal regions during meditation is thought to be directly related to a person’s ability to regulate their emotional responses.⁵ Magnetic resonance imaging (MRI) studies have shown that meditation can increase the gray matter density in the hippocampus.² Gray matter represents the concentration of cell bodies (as opposed to myelinated axon-rich white matter) and is known to decline with aging.⁶ Additionally, the increase in gray matter in the hippocampus in those who meditate may be responsible for these individuals’ long-term ability to implement positive emotions and habits in their routine. In fact, this phenomenon seems to be a positive feedback loop, where practicing mindfulness and positive thinking increases gray matter in the hippocampus, which then continuously promotes positive thinking and healthy habits. Interestingly, loss of gray matter volume in the hippocampus is considered a biomarker for Alzheimer’s disease (AD), so the increase in gray matter through meditation may help combat pathologies of aging that lead to AD propensity. In fact, only 12 minutes of meditation a day was able to improve several clinical symptoms of AD.⁷ Similarly, increases in hippocampal volumes are a side effect of selective serotonin reuptake inhibitors, which are commonly prescribed to patients with anxiety, depression, and related disorders, and this volume increase is correlated to the positive changes in behavior seen in patients on these medications.²

Another region that has been investigated regarding the effects of meditation is the PFC, which is involved in decision making, emotional regulation, and attention. After just four weeks of meditation, cortical thickness and cerebral blood flow in the PFC were increased, suggesting greater neuron branching, increased glial cell number (neuron support cells), and increased vasculature in the region.⁸ The increase in blood flow was particularly true in the anterior cingulate cortex (Figure 1), which is responsible for impulse control, empathy, and decision making.⁹ Reduced cortical thickness in the PFC has been described in patients with symptoms of AD, multiple sclerosis (MS), and even depression.^10–12 These data suggest meditation is an effective drug-free intervention for depressive disorders that are experienced by approximately 30% of the global population.¹³ In fact, a recent meta-analysis has found that mindfulness-based interventions have more consistent evidence of efficacy than medication for treating psychiatric disorders, particularly depression.¹⁴ While the relationship between meditation and disease prevention is simply correlative, it is important to highlight its potential impact on reversing or preventing structural changes to the brain that are broadly associated with illness.

How does meditation affect how the brain functions?

The effects of meditation could not be fully described without a discussion of the functional and connectivity differences in the brain. A key functional change occurs in the default mode network (DMN); a network of brain regions that activate during rumination and mind-wandering.¹⁵ Overactivity of this network is seen in various mental health disorders such as major depressive disorder and bipolar disorder. Meditation has been found to reduce the activity of the DMN thus promoting present-moment awareness and reducing self-referential thoughts.¹⁵ Outside the DMN, it has been found that practitioners of meditation have overall increased activity in regions associated with emotional regulation, such as the amygdala and insula, resulting in improved emotional regulation.¹⁶

How do these changes affect more than just my brain?

In addition to its effects on the brain, the practice of mindfulness and meditation is known to reduce the production of stress hormones.¹⁷ Chronic stress (A.K.A. grad school) can have negative effects on neuroplasticity. However, meditation was shown to increase BDNF, a cardinal marker for neuroplasticity, and decrease depression severity.¹⁷ Meditators also have lower circulating cortisol and IL-6; markers of stress and inflammation. Meditation has even been shown to improve cell health biomarkers in the body, such as decreased DNA damage, decreased reactive oxygen species, and increased telomerase activity, supporting the importance of the mind-body connection.¹⁷ And the benefits do not even end there!

Given the ability of meditation to reduce stress hormones, it is intuitive that this practice is also associated with lowering blood pressure in hypertensive patients.¹⁸ Surprisingly, these changes are even related to alterations in gene expression. Data suggest that individuals following guided meditation for just 20 minutes a day had increased expression of genes related to DNA repair, stress response, energy production, and immune cell signaling. These changes were complemented by a reduction in general inflammatory signals, directly relating to the changes in blood pressure that were observed.¹⁸ It is well known that high blood pressure promotes long-term heart disease, so by incorporating mindfulness into your daily routine, you can promote heart health and brain health!

I’m in! How do I start?

Do not be discouraged if you do not know how to start meditating! To begin, find a comfortable seat, set a timer (5 or 10 minutes is a great place to start), and begin to notice your mind wandering. When you notice where your train of thought is leading, see if you can meet it with kindness, not judgment, like watching clouds go by, and try to bring your focus back to your breath. Meditation is not about having an empty mind, or about keeping your mind from wandering; it is about noticing where your mind goes and greeting your thoughts with acceptance. There is no “right” or “wrong” way to meditate, as long as your practice calms your mind and encourages you to live in the present moment. Luckily, there is an abundance of resources available to help you incorporate mindfulness into your everyday routine if this article sparked your interest in promoting good brain health! Look over this guide which outlines how to begin meditating, or if you learn best with more structure, begin a Mindworks guided meditation course. Other guided meditation websites include Tara Brach (free), Headspace ($10/year for students), Art of Living (free), and many more. There are far too many amazing sources to share here, so we encourage you to search YouTube, podcast apps, and search engines to find meditation guides to help with anxiety, depression, attention-deficit, anger, sleep, or anything else you could imagine.

Everyone reading this possesses the power of altering their brain’s biology to improve their quality of life and prevent disease through the simple practice of meditation. We hope your understanding of the neuroscience of meditation will empower you to incorporate this free, easy, and accessible practice into your daily routine to cultivate a healthier mind and body.

TL:DR

• Meditation structurally and functionally changes the brain to reduce stress, prevent disease, and improve emotional regulation, attention, and resilience.
• EVERYONE is capable of obtaining the benefits of meditation!

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References

1. Yang, C.-C. et al. Alterations in Brain Structure and Amplitude of Low-frequency after 8 weeks of Mindfulness Meditation Training in Meditation-Naïve Subjects. Sci. Rep. 9, 10977 (2019).
2. Hölzel, B. K. et al. Mindfulness practice leads to increases in regional brain gray matter density. Psychiatry Res. Neuroimaging 191, 36–43 (2011).
3. Bartsch, T. & Wulff, P. The hippocampus in aging and disease: From plasticity to vulnerability. Neuroscience 309, 1–16 (2015).
4. Anand, K. S. & Dhikav, V. Hippocampus in health and disease: An overview. Ann. Indian Acad. Neurol. 15, 239–246 (2012).
5. Luders, E., Toga, A. W., Lepore, N. & Gaser, C. The underlying anatomical correlates of long-term meditation: Larger hippocampal and frontal volumes of gray matter. NeuroImage 45, 672–678 (2009).
6. Ramanoël, S. et al. Gray Matter Volume and Cognitive Performance During Normal Aging. A Voxel-Based Morphometry Study. Front. Aging Neurosci. 10, (2018).
7. Khalsa, D. S. Stress, Meditation, and Alzheimer’s Disease Prevention: Where The Evidence Stands. J. Alzheimers Dis. 48, 1–12 (2015).
8. Lazar, S. W. et al. Meditation experience is associated with increased cortical thickness. Neuroreport 16, 1893–1897 (2005).
9. Tang, Y.-Y., Lu, Q., Fan, M., Yang, Y. & Posner, M. I. Mechanisms of white matter changes induced by meditation. Proc. Natl. Acad. Sci. U. S. A. 109, 10570–10574 (2012).
10. Sailer, M. et al. Focal thinning of the cerebral cortex in multiple sclerosis. Brain J. Neurol. 126, 1734–1744 (2003).
11. Singh, V. et al. Spatial patterns of cortical thinning in mild cognitive impairment and Alzheimer’s disease. Brain J. Neurol. 129, 2885–2893 (2006).
12. Pink, A. et al. CORTICAL THICKNESS AND DEPRESSIVE SYMPTOMS IN COGNITIVELY NORMAL INDIVIDUALS: THE MAYO CLINIC STUDY OF AGING. J. Alzheimers Dis. JAD 58, 1273–1281 (2017).
13. Steel, Z. et al. The global prevalence of common mental disorders: a systematic review and meta-analysis 1980–2013. Int. J. Epidemiol. 43, 476–493 (2014).
14. Goldberg, S. B. et al. Mindfulness-based interventions for psychiatric disorders: A systematic review and meta-analysis. Clin. Psychol. Rev. 59, 52–60 (2018).
15. Brewer, J. A. et al. Meditation experience is associated with differences in default mode network activity and connectivity. Proc. Natl. Acad. Sci. 108, 20254–20259 (2011).
16. Creswell, J. D. et al. Alterations in Resting-State Functional Connectivity Link Mindfulness Meditation With Reduced Interleukin-6: A Randomized Controlled Trial. Biol. Psychiatry 80, 53–61 (2016).
17. Tolahunase, M. R., Sagar, R., Faiq, M. & Dada, R. Yoga- and meditation-based lifestyle intervention increases neuroplasticity and reduces severity of major depressive disorder: A randomized controlled trial. Restor. Neurol. Neurosci. 36, 423–442 (2018).
18. Bhasin, M. K. et al. Specific Transcriptome Changes Associated with Blood Pressure Reduction in Hypertensive Patients After Relaxation Response Training. J. Altern. Complement. Med. 24, 486–504 (2018).