Changes in EEG and autonomic nervous activity during meditation and their association with personality traits.

During Zen meditation, brainwave activity shifts toward increased fast theta and slow alpha power in the frontal area, while heart rate variability indicates greater parasympathetic and reduced sympathetic activity. These changes correlate with specific personality traits: increased slow alpha power, reflecting internalized attention, is linked to higher novelty seeking scores and reduced sympathetic indices; increased fast theta power, reflecting mindfulness, is linked to higher harm avoidance scores and greater parasympathetic activity. The findings suggest that internalized attention and mindfulness during meditation involve distinct psychophysiological and personality profiles.

Study at a glance

Abstract

Meditation is the attainment of a restful yet fully alert physical and mental state practiced by many as a self-regulatory approach to emotion management, but the psychophysiological properties and personality traits that characterize this meditative state have not been adequately studied. We quantitatively analyzed changes in psychophysiological parameters during Zen meditation in 20 normal adults, and evaluated the results in association with personality traits assessed by Cloninger's Temperament and Character Inventory (TCI). During meditation, increases were observed in fast theta power and slow alpha power on EEG predominantly in the frontal area, whereas an increase in the normalized unit of high-frequency (nuHF) power (as a parasympathetic index) and decreases in the normalized unit of low-frequency (nuLF) power and LF/HF (as sympathetic indices) were observed through analyses of heart rate variability. We analyzed the possible correlations among these changes in terms of the percent change during meditation using the control condition as the baseline. The percent change in slow alpha EEG power in the frontal area, reflecting enhanced internalized attention, was negatively correlated with that in nuLF as well as in LF/HF and was positively correlated with the novelty seeking score (which has been suggested to be associated with dopaminergic activity). The percent change in fast theta power in the frontal area, reflecting enhanced mindfulness, was positively correlated with that in nuHF and also with the harm avoidance score (which has been suggested to be associated with serotonergic activity). These results suggest that internalized attention and mindfulness as two major core factors of behaviors of mind during meditation are characterized by different combinations of psychophysiological properties and personality traits.