Within-Subject Reliability in fMRI Studies of Advanced Meditation

The science of meditation has taken a significant step forward with a new functional neuroimaging study by the Meditation Research Program at Massachusetts General Hospital and Harvard Medical School. The Meditation Research Program is affiliated with both the Mass General Department of Psychiatry and the Athinoula A. Martinos Center for Biomedical Imaging. The research was reported in May 2024 in Human Brain Mapping.

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In a recent conversation, Matthew Sacchet, PhD, director of the Meditation Research Program and a faculty member in the Department of Psychiatry, outlined the research, which investigated the reliability of functional MRI (fMRI) for the study of advanced meditation, and described what he and his team learned.

Q. What motivated the study?

Sacchet: The Meditation Research Program is focused on understanding scientifically what we call advanced meditation: skills, states, and stages of meditation practice that unfold with time and mastery. The neuroscience of advanced meditation is now emerging and promises to inform how we think about altered states of consciousness and associated psychological effects.

Our new research on advanced meditation has the potential to provide new insights into models of mental health, for example, incorporating previously unstudied aspects of human flourishing, including self-transcendence. Jhana is a type of advanced meditation from Buddhism that has been practiced for thousands of years. Jhana practice is characterized by the experience of several deep and rewarding qualities of mind, including joy, peace, and bliss.

To date, very little research has been conducted on advanced meditation, including jhana. This is in part because of the rarity of sufficiently adept meditators and the difficulties inherent in conducting scientific research on these states. The current study is important because it establishes strong proof of concept for the study of advanced meditation states and stages in controlled neuroimaging settings.

Q. What were the specific goals of the work?

Sacchet: We sought to investigate and establish the reliability of neural responses from repeated experiences of jhanas. Understanding the reliability of neural markers of advanced meditation is important because it facilitates future research. This is because evidence of reliability provides confidence in the meaningfulness of neural measures in this context.

The study is one of the very first to investigate within-subject functional MRI reliability at the level of brain networks. We developed a new approach called brain network intraclass correlation (ICC). This approach can be used to assess neural reliability using data from just a single subject who is intensively sampled. Notably, the invention of this new tool enabled us to examine the reliability of rarely studied jhana within a single subject.

Q. What was the most important finding of the study?

Sacchet: We found that several brain networks demonstrated strong reliability across repeated measurements. For a bit of context, there are eight jhana states, each with distinct experiential qualities. While some of the brain areas that were identified as reliable were engaged across all eight jhana, there were also other brain areas that were uniquely reliable during specific jhanas.

We also found that changes in 'phenomenology' (self-reported experiential aspects of distinct states of consciousness) were associated with the consistency of neuronal responses. That is, phenomenology accounted for improved reliability of neural markers.

Q. What else did you learn?

Sacchet: We were able to identify the most reliable brain areas involved in jhana as measured by functional MRI. This information can help facilitate increasingly rigorous, systematic, and precise neuroscientific investigations of jhana meditation, as well as advanced meditation more broadly.

In addition, the study has provided new evidence for the importance of incorporating detailed phenomenology in tandem with neural measurements, as doing so was shown to account for additional previously unexplained neuronal signals.

Q. What are the broader implications of the research for both the study and practice of meditation?

Sacchet: By combining ultra-high-field MRI, intensive phenomenological data sampling, brain network ICC and an advanced meditation technique with clearly articulated sequential stages (i.e., jhana), our study improves our ability to scientifically investigate advanced meditation and altered states of consciousness more broadly. The ultimate aim of this kind of research, and our study in particular, is to help make advanced meditation more accessible through evidence-based therapeutic avenues. The results of the current study are a step in that direction.

Moving forward, the Meditation Research Program will continue to develop the science of advanced meditation. We hope to contribute further neuroscientific insights to neuroscience models that will ultimately inform biology-informed treatments and methods for supporting advanced meditation practice. This may include developing technology-supported solutions that harness brain measurement to improve the accessibility and clinical and non-clinical effectiveness of advanced meditation for health and thriving.

Learn more about the Meditation Research Program

Learn more about the Martinos Center for Biomedical Imaging