Meditation and the Brain: What Imaging Studies Show and What They Do Not

Headlines often say meditation "changes your brain". Some studies do report differences on brain scans, but the picture is more mixed than the headlines. This page explains the main kinds of imaging study, what they found, and why a brain difference is not the same as a health benefit. It is information only.

Two kinds of study, two kinds of claim

• Comparing groups. Researchers scan experienced meditators and non-meditators. Any difference could come from meditation, or from who chooses to meditate, so this design cannot show cause.
• Training studies. Researchers scan people before and after a course. Randomized trials with a comparison group are the stronger version.

Imaging methods also differ. Structural MRI measures the size or density of brain tissue. Functional MRI (fMRI) measures activity or how regions work together over minutes.

Early findings: differences in meditators

A review pooling 21 studies of about 300 practitioners found eight brain regions that were consistently different in meditators, including regions linked to body awareness, memory and emotion regulation. [1] The average difference was medium in size, but the authors called publication bias and methodological limitations strong concerns and said more rigorous research is needed to link practice to brain structure. [1]

A review of 78 functional imaging studies found that brain activity patterns differed between meditation styles (focused attention, mantra, open monitoring and compassion practices). [2] Some areas, such as the insula, showed up across techniques, but the authors said convergence was the exception rather than the rule and raised many methodological concerns. [2] A broad review in Nature Reviews Neuroscience likewise said the underlying neural mechanisms remain unclear and that more rigorous studies are needed. [3]

Training studies: a promising result, then a null one

An early controlled study scanned 16 meditation-naive people before and after an 8-week MBSR course and compared them with 17 on a waiting list. It found increased gray matter concentration in the left hippocampus and other regions in the MBSR group. [4]

That small result was not borne out in a much larger test. Two combined randomized trials of 218 meditation-naive adults compared MBSR with a waitlist and a matched active control. [5] The authors found no evidence that MBSR produced structural brain changes compared with either control group, including in regions chosen from earlier MBSR studies. [5] They described the earlier studies as widely referenced despite major methodological limitations. [5]

A systematic review of 21 fMRI and 7 MRI studies of MBSR and MBCT programs and their components reported increased activity or volume in regions such as the prefrontal cortex, cingulate and hippocampus, and changes in amygdala activity. [6] That review was published before the large null result above. In other words: functional findings (how the brain acts) are somewhat more consistent than structural findings (the size of brain tissue), and neither is settled.

1. Experienced meditators differ on brain scans

   Mixed

   Differences found in pooled studies, with publication bias concerns [1]

2. An 8-week MBSR course changes brain structure

   Mixed, leaning against

   Small controlled study positive [4]; large randomized trials found no change [5]

3. Brain activity differs by meditation style

   Promising but limited

   Dissociable patterns, limited convergence [2]

4. Brain changes explain the health benefits

   Insufficient evidence

   Mechanisms remain unclear [3]

What imaging cannot tell you

Even a real brain change does not prove a health benefit. A critical review by a group of mindfulness researchers gave the intersection with brain imaging a particular focus in its agenda for better research, and warned that poor methodology may mislead the public. [7] A scan cannot say whether a practice will lower your anxiety, help your sleep or suit you. For that, we look at trials of symptoms and function; see does meditation work?.

Safe, sensible takeaways

• Treat "meditation shrinks the amygdala" or "grows gray matter" as unsettled. For the detail, see default mode network, amygdala and other brain claims checked.
• For brainwave claims, see meditation, EEG and brain waves.
• Choose a practice for how it feels and what your clinician or a trial supports, not for a brain image. Start with what meditation and mindfulness are.