Trait and state mindfulness modulate EEG microstates

The present study aimed to characterize microstate dynamics induced by non-reactive attention underlying mindfulness. Electroencephalogram signals from eighteen trained meditators and a matched non-meditators group were recorded before, during, and after a non-reactive attention meditation or during three resting periods respectively, while they were passively exposed to auditory stimulation. In a multimodal approach, microstate cluster decompositions, personality trait questionnaires, phenomenological ratings, and microstates sources localization were analyzed. Our results revealed that temporal parameters of microstates A and C at rest were negatively correlated to mindfulness traits across all participants. After meditation, the frequency of microstate A and C was decreased while microstate B was of longer duration, in meditators. Source localization analysis revealed that the non-reactive trait effect on microstate C at rest was explained by a modified activity of the salience network (identified by the anterior cingulate cortex, thalamus, and insula), while the non-reactive attentional state effect relied on a contribution of (anterior and posterior) cerebellum during meditation. Our results suggest that decreased microstates A and C reflect decreased mental state reactivity, while the increased microstate B relies on attention stability. These findings strongly encourage more research to assess the use of the microstate temporal parameters as a biomarker of the salience network activity, as well as objectify the brain changes induced by non-reactive attention training. HIGHLIGHTO_LIThe present study aimed to characterize microstate dynamics induced by non-reactive attention meditation, by the use of multimodal analysis including EEG microstate clusters decompositions, personality trait questionnaires, phenomenological reports, and source localization analysis. C_LIO_LIThe occurrence of microstate A, recognized to be related to phonological processing and depressive disorders, was negatively correlated to mindfulness trait and was decreased after non-reactive attention meditation. C_LIO_LIThe duration of microstate B, generally associated with the visual system, increases after meditation, in particular in meditators with a high non-reactivity trait. C_LIO_LITemporal parameters of microstate C, recognized to be related to default mode, were negatively correlated to the non-reactivity trait of meditators and were decreased after non-reactive attention meditation. Source analysis revealed that these trait and state effects reflect modified activities of the salient network. C_LI