Routine meditators also retain more brain cells, while the rest of us lose 4% of ours as we age.

According to set point theory, our attitude and behaviors have a bigger effect on our happiness than our external circumstances – and that’s good news for mindfulness. Mindfulness shapes our brain by increasing gray matter in areas related to attention, learning, self-awareness, self-regulation, empathy, and compassion.

Mindfulness literally changes our brains, making some areas more responsive, interconnected, and dense. In particular, these are areas related to empathy (the insula); memory, emotion, and emotion regulation; and reward circuitry. In response to distressing stimuli, meditators see more activation in their prefrontal structures (for awareness) and less in their fear-driven amygdala.

When our mind wanders during meditation, a group of brain areas called the “default mode network” activates. Scientists aren’t exactly sure what this network does – it may be directly involved in mind wandering or simply be carrying out brain maintenance when we aren’t thinking about anything in particular. As soon as we realize our mind is wandering during meditation, other brain regions for detecting relevant events light up. As we refocus our attention on the breath, the executive brain network takes over. Experienced meditators who repeat this process thousands of times start to show differences in the brain. They develop more connection between the self-focused part of the default mode network and brain regions for disengaging attention, which makes it easier to shut off that area of the brain when they realize their minds are wandering. Over time, meditation improves working memory, fluid intelligence, and standardized test scores.

Just having positive experiences is not enough to promote last well-being. If a person feels grateful for a few seconds, that’s nice. That’s better than feeling resentful or bitter for a few seconds. But in order to really suck that experience into the brain, we need to stay with those experiences for a longer duration of time—we need to take steps, consciously, to keep that spotlight of attention on the positive. So, how do we actually do this? These are the three steps I recommend for taking in the good. I should note that I did not invent these steps. They are embedded in many good therapies and life practices. But I’ve tried to tease them apart and embed them in an evolutionary understanding of how the brain works. 1. Let a good fact become a good experience. Often we go through life and some good thing happens—a little thing, like we checked off an item on our To Do list, we survived another day at work, the flowers are blooming, and so forth. Hey, this is an opportunity to feel good. Don’t leave money lying on the table: Recognize that this is an opportunity to let yourself truly feel good. 2. Really savor this positive experience. Practice what any school teacher knows: If you want to help people learn something, make it as intense as possible—in this case, as felt in the body as possible—for as long as possible. 3. Finally, as you sink into this experience, sense your intent that this experience is sinking into you. Sometimes people do this through visualization, like by perceiving a golden light coming into themselves or a soothing balm inside themselves. You might imagine a jewel going into the treasure chest in your heart—or just know that this experience is sinking into you, becoming a resource you can take with you wherever you go.

Another region is the frontal regions of the prefrontal cortex—areas involved in controlling attention. Again, this should be no surprise: They’re focusing their attention in their meditation, so they’re getting more control over it, and they’re strengthening its neural basis.

You can use the mind to change the brain to change the mind for the better. This is known as “self-directed neuroplasticity.” Neuroplasticity refers to the malleable nature of the brain, and it’s constant, ongoing. Self-directed neuroplasticity means doing it with clarity and skillfulness and intention. The key to it is a controlled use of attention. Attention is like a spotlight, to be sure, shining on things within our awareness. But it’s also like vacuum cleaner, sucking whatever it rests upon into the brain, for better or worse.

research has also shown that it’s possible to slow the loss of our brain cells. Normally, we lose about 10,000 brain cells a day. That may sound horrible, but we were born with 1.1 trillion. We also have several thousand born each day, mainly in the hippocampus, in what’s called neurogenesis. So losing 10,000 a day isn’t that big a deal, but the net bottom line is that a typical 80 year old will have lost about 4 percent of his or her brain mass—it’s called “cortical thinning with aging.” It’s a normal process. But in one study, researchers compared meditators and non-meditators. In the graph to the left, the meditators are the blue circles and the non-meditators are the red squares, comparing people of the same age. The non-meditators experienced normal cortical thinning in those two brain regions I mentioned above, along with a third, the somatosensory cortex. However, the people who routinely meditated and “worked” their brain did not experience cortical thinning in those regions.

People who maintain some kind of regular meditative practice actually have measurably thicker brains in certain key regions. One of those regions is the insula, which is involved in what’s called “interoception”—tuning into the state of your body, as well as your deep feelings. This should be no surprise: A lot of what they’re doing is practicing mindfulness of breathing, staying really present with what’s going on inside themselves; no wonder they’re using, and therefore building, the insula.

busy regions of the brain start stitching new connections with each other. Existing synapses—the connections between neurons that are very busy—get stronger, they get more sensitive, they start building out more receptors. New synapses form as well.

more activation in the left prefrontal cortex is associated with more positive emotions. So as there is greater activation in the left, front portion of your brain relative to the right, there is also greater well-being. That’s probably in large part because the left prefrontal cortex is a major part of the brain for controlling negative emotion. So if you put the breaks on the negative, you get more of the positive. On the other hand, people who routinely experience chronic stress—particularly acute, even traumatic stress—release the hormone cortisol, which literally eats away, almost like an acid bath, at the hippocampus, which is a part of the brain that’s very engaged in visual-spatial memory as well as memory for context and setting. For example, adults who have had that history of stress and have lost up to 25 percent of the volume of this critically important part of the brain are less able to form new memories.

And better understanding them means we can skillfully stimulate the neural substrates of those states—which, in turn, means we can strengthen them. Because as the famous saying by the Canadian scientist Donald Hebb goes, “Neurons that fire together, wire together.”

during periods of mind-wandering, regions of the brain’s default mode network were activated. Then when participants became aware of this mind-wandering, brain regions related to the detection of salient or relevant events came online. After that, areas of the executive brain network took over, re-directing and maintaining attention on the chosen object. And all of this occurred within 12 seconds around those button presses.

A particularly generative field is contemplative neuroscience, which involves collaborations between scientists and expert authorities in the traditions that have informed the concept of mindfulness.

For example, when your mind wandered off in that meeting, it might help to know you’re slipping into default mode—and you can deliberately bring yourself back to the moment. That’s an ability that can improve with training.

One brain area stood out in this analysis: the medial prefrontal cortex, a part of the default mode network that is particularly related to self-focused thoughts, which make up a good portion of mind-wandering content. It turns out that experienced meditators deactivated this region more quickly after identifying mind-wandering than people who hadn’t meditated as much

more experienced meditators have increased connectivity between default mode and attention brain regions, and less default mode activity while meditating.