Long-term meditation is associated with increased gray matter density in the brain stem.
Neuroreport January 28, 2009 Peter Vestergaard‐Poulsen, Martijn van Beek, Joshua Skewes et al.
Long-term meditation practice is associated with structural differences in the lower brainstem, specifically higher gray matter density in regions involved in cardiorespiratory control. Using magnetic resonance imaging, experienced meditators showed greater gray matter density in lower brainstem regions compared to age-matched nonmeditators. These structural differences may explain cardiorespiratory parasympathetic effects and traits, as well as cognitive, emotional, and immunoreactive impacts observed in studies of various meditation practices.