Individual ThoughtChart Shows Task Differences in EEG of Meditators and Healthy Individuals

Experienced meditators can be a promising group of healthy subjects for brain connectivity analysis due to their demonstrable differences in resting state dynamics, and altered brain connectivity has been implicated as a potential factor in several psychiatric disorders. Three distinct techniques of meditation are explored: Isha Yoga, Himalayan Yoga, and Vipassana, as well as a meditation-naïve group of individuals. All individuals participated in a breath awareness task, a autobiographical thinking task, a counting task, and their own form of meditation if they had one, while being recording by a 64-electrode electroencephalogram (EEG). The brain connectivity was estimated using weighted phase lag index (WPLI) and the connectivity dynamics were investigated using a novel individual form of ThoughtChart, a previously reported dimensionality reduction method which utilizes manifold learning. The breath awareness task in all groups was found to have consistently different functional connectivity patterns than the autobiographical thinking tasks in each individual. The meditation task was found to be most similar to the breath awareness task in all groups, as expected in meditation traditions which incorporate breath awareness in their practice. Finally, the speed of connectivity changes, conceived of here as the speed of thought, in Vipassana practitioners correlated with their Toronto Mindfulness Scale score. These results demonstrate that the individual form of ThoughtChart consistently and reliably separates similar tasks among healthy meditators and non-meditators during resting state-like EEG recordings.