Meditation and Neuroplasticity
Last week, we raised the astonishing proposition that we may be able to rebuild our brains. Well, if not actually rebuild, at least direct our minds to focus on a bit of minor repair work.
The principle is called neuroplasticity. A simple example is learning a musical passage. The formation of new memories involves physical changes in our neural circuitry. New studies are suggesting that repeated effort can accomplish a lot more.
In that same piece from last week, we showcased a study that found that London taxi-drivers, who must memorize a tangle of 25,000 streets, have larger hippocampi - an area associated with laying down memories - than the population at large. A follow-up study concluded that it wasn’t that the cabbies simply had larger hippocampi to begin with - before and after brain scans revealed significant growth taking place.
As well as laying down memories, the hippocampus is also involved in mood regulation. Brain scans of people exposed to depression or trauma reveal reduced hippocampal volume. Meanwhile, a larger amygdala - associated with fight-or-flight - is linked to anxiety and other ills.
So forget for now everything you may have read about "chemical imbalance." If we are going to talk about any kind of imbalance, maybe we need to consider what happens when that 90-pound weakling of a hippocampus is forced to compete with a bulked-up amygdala. I’ve never had my brain scanned, but I am pretty sure what a picture of mine would look like.
Now imagine if you could direct your brain to physically restore balance, and, for good measure, enhance some of the gray matter in your cortical regions. Sound too good to be true? Read on "
Sara Lazar is a neuroscientist at Harvard. In a TEDx Talk delivered in 2011, she related how she took up yoga strictly as an exercise regimen. As a scientist, Dr Lazar admitted to rolling her eyes in response to her instructor’s New Age claims about yoga increasing compassion and opening up the heart and all the rest.
Funny thing, though: "After a couple of weeks, I started noticing some of these changes." She observed that she was calmer and in better shape to handle difficult situations. Not only that, she felt more compassionate toward others. Curious, she discovered a substantial body of research linking yoga and meditation to reduced depression, anxiety, pain, and insomnia, plus enhanced ability to pay attention and improved quality of life.
She also pulled up a study that showed three months of juggling changed the parts of the brain responsible for detecting visual motion. What about mediation? she wondered.
In her first study, she recruited a group of people who practiced meditation for 30 to 40 minutes a day and compared their brain scans to a matched group of non-meditators. The results showed thicker cortical grey matter in the meditators. As we age, grey matter is expected to become thinner, but the older meditators’ brains were indistinguishable from those half their age.
A follow up study performed before-and-after scans on a group of non-meditators receiving an eight-week meditation course. You guessed it - massive increase in the hippocampus. There was also an increase in the temporal parietal junction, associated with, among other things, empathy and compassion. And, last but not least, a decrease in the amygdala. Not only that, the greater the reduction the subjects reported in their stress the smaller the amygdala.
The smaller amygdala finding paralleled in reverse findings of studies done on rodents. You can’t exactly teach rats and mice to meditate, but you can subject them to stress. Lo and behold - at the end of ten days, these on-edge critters had larger amygdalae. After being left alone for three weeks, the researchers found the rodents’ amygdalae remained large, and that they stayed stressed.
Back to the humans, Dr Lazar pointed out that nothing had changed in their environment. They still had their same stressful jobs. The economy still sucked. Yet their amygdalae got smaller and they reported less stress. As Dr Lazar concluded: "So the idea I would like to share with you today is that meditation can literally change your brain."
Is there hope for us?
More to come "
John is an author and advocate for Mental Health. He wrote for HealthCentral as a patient expert for Depression and Bipolar Disorder.