Brain images in the meditation group revealed increases in gray matter concentration in the left hippocampus. The hippocampus is an area of the brain involved in learning, memory, and emotional control, and is suspected of playing a role in producing some of the positive effects of meditation. Gray matter also increased in four other brain regions (though not in the insula, a region that has shown changes in other meditation studies) in the meditation group. Responses to the questionnaire indicated improvements in three of the five aspects of mindfulness in the mediators, but not the control group.
The researchers concluded that these findings may represent an underlying brain mechanism associated with mindfulness-based improvements in mental health. Additional studies are needed to determine the associations between specific types of brain change and behavioral mechanisms thought to improve a variety of disorders.