One of the enduring changes in the brain of those who routinely meditate,is that the brain becomes thicker.

"One of the enduring changes in the brain of those who routinely meditate,is that the brain becomes thicker. In other words, those who routinely meditate build synapses, synaptic networks, and layers of capillaries (the tiny blood vessels that bring metabolic supplies such as glucose or oxygen to busy regions), which an MRI shows is measurably thicker in two major regions of the brain. One is in the pre-frontal cortex, located right behind the forehead. It’s involved in the executive control of attention – of deliberately paying attention to something. This change makes sense because that’s what you're doing when you meditate or engage in a contemplative activity."
"The second brain area that gets bigger," he further notes, "is a very important part called the insula. The insula tracks both the interior state of the body and the feelings of other people, which is fundamental to empathy. So, people who routinely tune into their own bodies – through some kind of mindfulness practice – make their insula thicker, which helps them become more self-aware and empathic. This is a good illustration of neuroplasticity, which is the idea that as the mind changes, the brain changes, or as Canadian psychologist Donald Hebb put it, neurons that fire together wire together."