Alterations in the structure of the brain — review & implications

Fox, Kieran C. R., & Rael B. Cahn. (2018). “Meditation and the brain in health and disease.” Forthcoming in The Oxford Handbook of Meditation, Farias, Brazier, & Lalljee, Eds. Full text.

The aim of this chapter is to provide an accessible introduction to the neuroscience of meditation. First, we review studies examining the relationship between meditation and alterations in the structure of the brain’s grey and white matter (so-called morphometric neuroimaging).

Next, we discuss findings from functional neuroimaging methods, such as functional magnetic resonance imaging (fMRI) and positron emission tomography (PET) scans, and what they have taught us about the brain’s patterns of activity during different forms of meditation, how meditation alters the brain’s response to various tasks and experiences, and how the expertise of long-term meditators might be harnessed to help us explore subtle aspects of human cognition.

Third, we review electrophysiological methods of measuring brain activity during meditation, such as electroencephalography (EEG), and how these findings relate to what we have learned from morphometric and functional neuroimaging.

Finally, we discuss the implications of this research and of meditation more generally for brain health and psychological well-being. Specifically, we focus on how meditation might ameliorate the deficits related to cognitive aging, as well as help ameliorate the symptoms and underlying neural substrates associated with neurodegenerative and psychiatric disease.

Brain regions associated with attention may differ between long- and short-term meditators

Baron Short, E., et al. (2010). Regional brain activation during meditation shows time and practice effects: an exploratory FMRI study. Evidence-Based Complementary and Alternative Medicine, 7(1), 121-127. Full text via abstract.

Excerpts: Meditation involves attentional regulation and may lead to increased activity in brain regions associated with attention such as dorsal lateral prefrontal cortex (DLPFC) and anterior cingulate cortex (ACC). Using functional magnetic resonance imaging, we examined whether DLPFC and ACC were activated during meditation. Subjects who meditate were recruited and scanned on a 3.0 Tesla scanner.

Subjects meditated for four sessions of 12 min and performed four sessions of a 6 min control task. Individual and group t-maps were generated of overall meditation response versus control response and late meditation response versus early meditation response for each subject and time courses were plotted. For the overall group (n = 13), and using an overall brain analysis, there were no statistically significant regional activations of interest using conservative thresholds.

A region of interest analysis of the entire group time courses of DLPFC and ACC were statistically more active throughout meditation in comparison to the control task. Moreover, dividing the cohort into short (n = 8) and long-term (n = 5) practitioners (>10 years) revealed that the time courses of long-term practitioners had significantly more consistent and sustained activation in the DLPFC and the ACC during meditation versus control in comparison to short-term practitioners.

The regional brain activations in the more practised subjects may correlate with better sustained attention and attentional error monitoring. In summary, brain regions associated with attention vary over the time of a meditation session and may differ between long- and short-term meditation practitioners.