Brain criticality and advanced meditation "cessation" events: An intensively sampled electroencephalography case study.

Advanced meditation includes meditative endpoints that are outcomes of meditation practice and occur with time and mastery of meditation. The "cessation" event (c.f. nirodha in Theravada Buddhism) is a meditative endpoint characterized by a loss of consciousness followed by a sense of mental reset and deep clarity. In general, organization of brain activity exists along a "criticality" spectrum: order and disorder occupy the extremes, and the critical point, which is thought to represent optimal information processing, is in between. In this exploratory, hypothesis-generating case study, we assessed brain criticality in the 39.9 s pre-cessation to 39.9 s post-cessation window by applying detrended fluctuation analysis (DFA) to electroencephalography (EEG) data in relation to 37 cessations in a single advanced meditator. Changepoint analysis and linear mixed effects modeling revealed a spike in the whole-brain DFA exponent starting from 11.3 to 3.1 s pre-cessation, suggesting a strengthening of long-range temporal correlations (LRTC) and movement towards the critical point. In addition, a sustained elevation was observed from 3.1 to 23.6 s post-cessation. Linear changepoint analysis effects were most pronounced in central, right frontal, and posterior EEG channels, while frontal channels Fp1, F3, and F7 incurred into supercritical territory surrounding cessations. Additional analysis revealed a temporary drop in the mean DFA exponent around cessation onset relative to immediately surrounding segments. For most channels, the mean DFA exponent reached a time series maximum at 1.0-3.1 s following cessation onset, often near the critical point or just into the supercritical range. These preliminary findings in a single case study, which are consistent with reported phenomenology of cessations, show large-scale modulation in criticality related to cessations.