A review of the methodology, taxonomy, and definitions in recent fMRI research on meditation

Objectives: As meditation is increasingly employed for the promotion of good health, there is a growing interest in using neuroimaging methods to investigate the neural mechanisms by which meditation acts. In the wake of this rising interest, criticism regarding the lack of clarity concerning theory, definitions, and taxonomy, as well as deficient or poorly reported methodology, has arisen. The aim of this study was to investigate trends in current neuroimaging research on meditation and to provide guidelines for future studies. Methods: We made a literature search for articles published during 2016–2019 using the search phrases “meditation” and “functional magnetic resonance imaging or fMRI”. Inclusion criteria were limited to meditation studies using resting-state fMRI or such task-based fMRI examinations that were specifically targeting meditative states in healthy participants. Text analysis was performed using Nvivo 12 Mac (QSR International). Results: Twenty-eight articles were included from which we identified four different intention-based dimensions of meditation practice: The present moment, Wholesome qualities to cultivate, Unwholesome qualities to avoid, and Attitudes. Half of the studies do not make assessments of subjective experience. The results were related to networks and brain regions describing cognitive, affective, somatic, and self domains of brain function. Most studies describe meditation-related brain function in terms of “processes”. Conclusions: We defined five areas of potential improvement regarding research methodology: (1) Provide clear and unambiguous definitions of constructs and practices, (2) Include measures of subjective experience, (3) Perform correct assessment of processes, (4) Combine methodologies for more substantiated conclusions, (5) Avoid the risk of overinterpretation