Brain Criticality and Complexity: An Analysis in the Meditative State

Meditation practices are widely recognized as promising approaches for enhancing physical and mental well-being, yet the mechanisms underlying their effects remain only partially understood. In this study, we examine how meditation influences brain activity by analyzing electroencephalographic (EEG) signals from three groups of experienced meditators (Himalaya Yoga Tradition, Vipassana, and Isha Shoonya Yoga) and a control group. The EEG dataset, publicly available, was collected at the Meditation Research Institute (MRI) in Rishikesh, India [1]. Participants completed two 20-minute sessions: one of meditation and one of mind wandering. During the first 10 minutes of the meditation session, they were instructed to focus exclusively on their breath. From the preprocessed EEG recordings, we computed several measures related to neural complexity and criticality, including Higuchi Fractal Dimension, Lempel–Ziv complexity, Long-Range Temporal Correlations, Power Spectral Density, the slope of the aperiodic component of the power spectrum, and Sample Entropy. By comparing three conditions (breath focus, meditation, and mind wandering) within each group, we observed that changes in brain criticality and complexity characteristic of the meditative state emerge already during the breath-focused phase. These findings shed light on early neural mechanisms associated with meditation. Finally, we applied a Random Forest classifier to assess which of these features best discriminate the meditative state from the other conditions.