Meditation not only changes our mind but also our brain – this is what more and more neuroscientific research suggests.
Neuroplasticity – the change of brain structures as a result of experience – is considered to be one of the most important discoveries of neuroscience. Over the last 10 years evidence has been growing that not only the acquisition of navigational knowledge by London Taxi drivers (see video) or learning a new motor task like juggling (see article), but also meditation practice can lead to significant changes to brain structures. Here I respond to a recent request and list five key articles on that topic.
Article 1: Meditation experience is associated with increased cortical thickness
To my knowledge this is the first study showing differences in brain structure between meditators and non-meditators. Magnetic Resonance Imaging (MRI) revealed that experienced meditators had a thicker cortex than non-meditators. This was particularly true for brain areas associated with attention, interoception and sensory processing.
Lazar, S. W., Kerr, C. E., Wasserman, R. H., Gray, J. R., Greve, D. N., Treadway, M. T., … & Fischl, B. (2005). Meditation experience is associated with increased cortical thickness. Neuroreport, 16(17), 1893-1897. [pdf]
Article 2: Long-term meditation is associated with increased gray matter density in the brain stem
This study compared long-term meditators with age-matched controls with Magnetic Resonance Imaging and found structural differences in regions of the brainstem that are known to be concerned with mechanisms of cardiorespiratory control.
Vestergaard-Poulsen, P., van Beek, M., Skewes, J., Bjarkam, C. R., Stubberup, M., Bertelsen, J., & Roepstorff, A. (2009). Long-term meditation is associated with increased gray matter density in the brain stem. Neuroreport, 20(2), 170-174. [pdf]
Article 3: The underlying anatomical correlates of long-term meditation: larger hippocampal and frontal volumes of gray matter
Another study that compared long-term meditators with matched control participants. The main findings were that meditators had larger gray matter volumes than non-meditators in brain areas that are associated with emotional regulation and response control (the right orbito-frontal cortex and the right hippocampus).
Luders, E., Toga, A. W., Lepore, N., & Gaser, C. (2009). The underlying anatomical correlates of long-term meditation: larger hippocampal and frontal volumes of gray matter. Neuroimage, 45(3), 672-678. [pdf]
While the studies listed so far merely compared existing differences between meditators and non-meditators and thus do not provide information of causality (a possible explanation would be that these people were drawn to meditation because their brains are different – rather than the difference being a result of meditation), below are two studies demonstrating actual impact of meditation practice by means of longitudinal designs (comparing pre- and post-meditation brain scans).
Article 4: Mindfulness practice leads to increases in regional brain gray matter density
Compared to a control group participation in an 8-week Mindfulness-Based Stress Reduction (MBSR) programme resulted in increased grey matter in the left hippocampus, a brain area strongly involved in learning and memory.
Hölzel, B. K., Carmody, J., Vangel, M., Congleton, C., Yerramsetti, S. M., Gard, T., & Lazar, S. W. (2011). Mindfulness practice leads to increases in regional brain gray matter density. Psychiatry Research: Neuroimaging, 191(1), 36-43. [pdf]
Article 5: Mechanisms of white matter changes induced by meditation
Here we have a very exciting study showing the impact of meditation practice on the connections between brain areas using Diffusion Tensor Imaging (DTI). After only four weeks of meditation changes in white matter – which is strongly involved in interconnecting brain areas [see myelin] – were present in those participants who meditated but not in the control participants who engaged in relaxation exercises. Interestingly, these changes involved the anterior cingulate cortex, a part of the brain that contributes to self-regulation, an important aspect when people start engaging with meditation practice. (read more about this article in a previous post )
Tang, Y. Y., Lu, Q., Fan, M., Yang, Y., & Posner, M. I. (2012). Mechanisms of white matter changes induced by meditation. Proceedings of the National Academy of Sciences, 109(26), 10570-10574. [pdf]