Meditation appears to increase the complexity of neural activity during practice, compared to resting or mind-wandering, but experienced meditators show lower baseline complexity as a lasting trait. This systematic review of studies on neural complexity in meditation examined different measurement approaches, short-term state effects, and long-term trait effects across meditation styles. The findings converge on a pattern where the meditative state enhances neural complexity, while trait effects in seasoned practitioners show reduced baseline complexity relative to novices and non-meditators. The review provides a framework to guide future research.
The sense of being a bounded self can be attenuated or dissolved while awareness remains. Analyzing magnetoencephalography data from 46 long-term meditators, the study found that both meditation conditions (self-boundary dissolution and maintenance) increased broadband entropy rate and directed information transfer compared to rest, driven mainly by high-frequency activity. Localized reductions in information transfer from the anterior cingulate to posterior cingulate and in high-beta entropy rate in sensorimotor and posterior-medial cortices differentiated the two meditation conditions. Reduced orbitofrontal cortex entropy rate and reduced information transfer from occipital, cingulate, limbic, and subcortical areas correlated strongly with self-boundary dissolution phenomenology. Together with a previously reported neural correlate of reduced high-beta power in the posterior-medial cortex, these two neural correlates explained over half the variance in phenomenological dissolution scores (R² = 0.52).