Mindfulness Training Reduces Stress and Amygdala Reactivity to Fearful Faces in Middle-School Children

The impact of mindfulness training on stress and associated brain plasticity has been shown in adults, whereas the impact of such training in the developing brain remains unknown. To address this open question, 40 middle-school children were randomized to either mindfulness or coding training (active control) interventions during the school day for eight weeks. Outcome measures were ratings of self-perceived stress and right amygdala activation while viewing fearful, happy, and neutral facial expressions during functional MRI. Prior to intervention, greater stress correlated with greater right amygdala activation in response to fearful versus neutral facial expressions across all children. After intervention, children who received mindfulness training reported lower stress associated with reduced right amygdala activation to fearful faces relative to children in the control condition. Amygdala responses to happy faces were unrelated to either initial stress or mindfulness reduction of stress. Moreover, mindfulness training led to relatively stronger functional connectivity between the right amygdala and ventromedial prefrontal cortex during the viewing of fearful facial expressions. Changes in perceived stress and neuroplasticity occurred in nonmeditative states, indicating that the benefits of mindfulness training generalized beyond the active meditative state. This study provides initial evidence that mindfulness training in children reduces stress and promotes functional brain changes and that such training can be integrated into the school curriculum for entire classes. This study also reveals first evidence that a neurocognitive mechanism for both stress and its reduction by mindfulness training is related specifically to reduced amygdala responses to negative stimuli.