Although it is extremely difficult to isolate a specific mental function to a particular brain region (and the results of efforts to do so are controversial in the scientific community), the particular areas that Lazar identified in the frontal cortex are essential for a variety of critically important capabilities. The prefrontal cortex manages higher cognitive “executive” functions like planning, decision-making, and judgment, and keeps us out of trouble by facilitating socially appropriate behavior. It allows us to hold two concepts or experiences in mind simultaneously so that we can compare and evaluate plans, ideas, and memories. It also helps us to link memory with sensory input so we can connect what we have learned from the past with what is happening in the present moment.

The other major region identified by Lazar, the insula, seems to integrate sensation and emotion, and to process social emotions—such as empathy and love. It is thought to be essential for the capacity for self-awareness. Although no region of the brain is unimportant, the activities supported by these brain areas are especially crucial for our effective functioning in the world.

This research is still viewed as preliminary, partly because it contradicts a lot of what we thought we knew, and partly because it studied only twenty meditators. Lazar says that among her scientific peers, some are enthusiastic while others are skeptical. Subsequently, however, Lazar’s work was confirmed by a researcher in Germany, Britta Hölzel, who also found additional regions, hidden more deeply within the brain, that had increased gray matter density in meditators. Gray matter is the part of the brain that holds most of the actual brain cells; its increased density may reflect an increase in connectivity between the cells. Hölzel, who is a meditation practitioner as well as a researcher, now works with Lazar in Boston. The regions that Hölzel and Lazar identified are areas that are associated with the kinds of psychological and behavioral changes reported by meditators for millennia.

One of these regions allows us to shift perspective, an ability that supports a variety of skills and behaviors, including empathy (when we take the perspective of another) and the management of emotional upheavals (when we step out of our reactivity). This is completely in keeping with what actually happens during mindfulness practice. The shift of perspective from automatic-pilot reactivity to a more aware and observant witness is a central component of meditation training. Over and over, you practice shifting from a dreamy nonawareness into the vividness of the present moment. Lazar and Hölzel have also recently reported that the region of the brain most associated with emotional reactivity and fear—the amygdala—has decreased gray matter density in meditators who experience less stress. The most surprising finding was that both of these types of structural brain changes were seen after only eight weeks of practice in a Mindfulness-Based Stress Reduction program.

Hölzel says her neuroscience research has been extremely helpful in her own mindfulness practice. “It helps me to refine my practice, to be more aware of the processes that are going on while I’m practicing,” Hölzel says. “It also helps me to cultivate patience and acceptance. You might think that it should be easy to quiet your mind, but I know that neural systems take time to change, and wandering is built into the system. That knowledge allows me to accept how it is right now for me. It’s not my fault or my problem. It is simply the way that the brain is built and how the system functions.”

The benefit of this information for practitioners is confirmed by Lazar. “The thing that surprised me most about this research,” Lazar says, “is how many senior practitioners and meditation teachers say that it motivates them to practice during the times when their meditation seems to be going nowhere.” She says meditators often tell her, “I used to think that I was wasting my time because my mind was all over the place. This helps to keep me on the cushion because I remember how significant these changes are.”