Neuroscience has confirmed that meditation produces measurable changes in brain structure and function. Studies using MRI show that long-term meditators have increased gray matter density in the prefrontal cortex (associated with attention and decision-making) and reduced gray matter in the amygdala (associated with stress and fear responses). Harvard researchers found that just 8 weeks of mindfulness meditation increased cortical thickness in areas related to awareness and reduced the size of the amygdala. The field of contemplative neuroscience — pioneered by Richard Davidson at the University of Wisconsin — continues to map exactly how meditation reshapes the brain.

Reference:

Wikipedia: Research on Meditation

https://en.wikipedia.org/wiki/Research_on_meditation