EEG alpha-theta dynamics during mind wandering in the context of breath focus meditation: an experience sampling approach with novice meditation practitioners

Summary

Mind wandering during breath focus meditation is linked to specific changes in brain waves. In 25 novice meditators, episodes of mind wandering showed increased amplitude and decreased frequency of theta oscillations (4-8 Hz), while alpha oscillations (8-14 Hz) decreased in amplitude and increased in frequency. Mind wandering also involved greater harmonicity and phase synchrony between theta and alpha rhythms. These spectral changes resemble those seen in controlled cognitive processes like memory and executive control, suggesting shared neurocognitive mechanisms. The findings indicate that theta-alpha oscillatory activity could serve as a basis for EEG-neurofeedback protocols to detect mind wandering during meditation.

Study at a glance

Abstract

Meditation practice entails moments of distraction dominated by self-generated thoughts (i.e. mind wandering). Initial studies assessing the neural correlates of mind wandering in the context of meditation practice have identified an important role of theta (4-8 Hz) and alpha (8-14 Hz) neural oscillations. In this study, we use a probe-caught experience sampling paradigm to assess spectral changes in the theta-alpha frequency range during mind wandering in the context of breath focus meditation. Electroencephalography (EEG) was measured in 25 novice meditation practitioners during a breath focus task in which they were repeatedly probed to report whether they were focusing on their breath or thinking about something else. Mind wandering episodes were associated with an increase in the amplitude and a decrease in the frequency of theta (4-8 Hz) oscillations. Conversely, alpha oscillations (8-14 Hz) were shown to decrease in amplitude and increase in frequency during mind wandering relative to breath focus. In addition, mind wandering episodes were shown to be accompanied by increased harmonicity and phase synchrony between alpha and theta rhythms. Because similar spectral changes in the theta-alpha frequency range have been reported during controlled cognitive processes involving memory and executive control, we speculate that mind wandering and controlled processes could share some neurocognitive mechanisms. From a translational perspective, this study indicates that oscillatory activity in the theta-alpha frequency range could form adequate parameters for developing EEG-neurofeedback protocols aimed at facilitating the detection of mind wandering during meditation practice.