La caractérisation neuromagnétique de l'attention sans réflexion chez les méditants zen dans un contexte d'images visuelles négatives
Non-elaborative attentional stance, called mindfulness, demonstrated many positive clinical effects on emotional disorders associated with various medical conditions. The amount of scientific papers addressing the neuronal basis of this attentional stance increases but there is still a need to further investigate, in order to potentially improve clinical interventions. The present study aims to determine, by use of magnetoencephalography, which brain regions correlate with mindfulness in experts, namely, zen meditators. These people cultivate a state in which they abstain from rejecting or seeking sensorial phenomena. In a context of emotional visual stimulation, meditators were instructed to observe images with mindfulness (experimental condition) or without making any effort to do so (control condition). Results suggest that participants experienced less intense emotions in a state of mindfulness: both subjective ratings and an evoked brain response known to be related to emotional intensity, the magnetic Late Positive Potential (mLPP), suggest this. However, the most statistically convincing result surpasses the emotional nature of the presented stimuli. It is a sustained diminution of induced oscillations in the gamma band localized in visual associative regions of the right temporal lobe, regardless of the emotional nature of stimuli. Additionally, mindfulness is associated to a suppression of gamma activity in the left lateral prefrontal cortex. This may indicate a diminution of language-mediated conceptualization of visual stimuli and self-reflective processes. Those results bring a new light on the neural substrate of mindfulness, mostly studied with more limited brain imaging techniques on the level of temporal resolution.
Emotion Mindfulness Zen Buddhism Magnetoencephalography Emotional regulation Gamma frequency Late positive potential Meditation Brain