And what was interesting was that in this one region, the 50 year old meditators had the same amount of cortex as the 25 year olds, suggesting that meditation practice may actually slow down or prevent the natural age-related decline in cortical structure.
So now, the critics, and there were many critics, said, well, you know, meditators, they’re weird. Maybe they were just like that before they started practicing, right? A lot of them were vegetarian, so maybe it had something to do with their diet, or something else with their lifestyle, you know. Couldn’t possibly be the meditation, it’s something else, right?
And to be fair, you know, that could be true. This first study could not address that. So we did a second study.
In this study, what we did is, we took people who had never meditated before, and we put them in the scanner, and then we put them through an eight-week meditation-based stress reduction program where they were told to meditate every day for 30 to 40 minutes. And then we scanned them again at the end of the eight weeks, and this is what we found.
So what you see is that several areas became larger. In this slide we can see the hippocampus, and in the graph, the controls are in blue and the meditation subjects are in red, and what we see is that the hippocampus, this is the area that’s important for learning and memory, it’s also important for emotion regulation and it was interesting it was less gray matter in this region in people who had depression and PTSD.
Another region we identified was the temporoparietal junction which is here above your ear, it’s important for perspective taking and empathy and compassion. And again, these are both functions which people report changing when they start practicing meditation and yoga.
Another region we identified was the amygdala. And the amygdala is the fight-or-flight part of your brain. And here we actually found a decrease in gray matter. And what was interesting was that the change in gray matter was correlated with the change in stress. So the more stress reduction people reported, the smaller the amygdala became. And this was really interesting, because it’s sort of opposite and parallel of what some animal studies have shown.
So Chatterjee and colleagues using rodents, they took rodents who were just happy, normal rodents, and they had them in their cage, and they measured their amygdala, and then they put them through a ten- day stress regimen. And at the end of the ten days, they measured their amygdala, and this exact same analogous part of the rat brain grew. So we found a decrease with stress, they found an increase with stress.
What was interesting was that then they left the animals alone, and three weeks later they went back and tested them again. And three weeks later, that same part of the amygdala was still large, and the animals, even though they were in their original cages where they were happy, were still acting stressed out, so they were cowering in the corner, and they just weren’t exploring the space the way they had before.
And so, this is the exact opposite of what we saw at the humans, because with the humans nothing has changed with their environment. They still had their stressful jobs, all the difficult problems still being difficult, and the economy still sucks, but yeah, their amygdala got smaller, and they were reporting less stress.
And so, together these really show that the change in the amygdale is not responding to the change in the environment, but rather it’s representing the change in the people’s reaction or relationship to their environment.
And then the other thing that the study shows is that, it wasn’t just the people were saying, “Oh, I feel better.” Or that it was a placebo response, or that they’re trying to please us, but there was actually a neurobiological reason why they’re saying they felt less stressed.
And so the idea that I’d like to share with all of you today is that meditation can literally change your brain.