Opening Peas by Melina Meza
"Stress can damage the brain. The hormones it releases can change the way nerves fire, and send circuits into a dangerous feedback loop, leaving us vulnerable to anxiety, depression and post-traumatic stress disorder.” — Geoffrey Mohan, LA TimesOne of my new areas of interest is brain health. Yes, not too surprisingly, I’d like to keep my brain—along with my body—healthy as I age (as I’m sure you all do, too). And one thing I’ve been noticing lately in my research is that chronic stress is as bad for the brain as it is for the body. In a way, that makes sense because really your brain is just another organ in your body, and we all know that chronic stress takes a toll on other organs, such as your heart and your digestive system. But I was fascinated to read recently in Stress matters to brain's white matter that neuroscientists at the University of California found evidence that cortisol, one of the stress hormones, trips a switch in stem cells in the brain, causing them to produce white matter cells that can change the way circuits are connected in the brain.
In a study published in Nature, Stress and glucocorticoids promote oligodendrogenesis in the adult hippocampus, researchers examined stem cells in the brain’s hippocampus. (The hippocampus plays an important role in the consolidation of information from short-term to long-term memory and spatial navigation. And in Alzheimer’s disease, the hippocampus is one of the first regions of the brain to suffer damage.) Under normal circumstances, these stems cells in the hippocampus form new neurons or glia, a type of white matter. But after examining the brains of mice that were chronically stressed out (yes, they’re stressing out those poor mice again), the researchers discovered that the stress hormone corticosterone (the rodent equivalent of cortisol in humans) causes the stem cells produce instead an abundance of oligodendrocytes. The LA Times quoted Daniela Kaufer, lead investigator of the study:
“Usually the brain doesn’t make much oligodendrocytes in adulthood from those neural stem cells. But under stress, all of a sudden, you discover they are making those cells.”
She observed that moderate stress, such as that produced by studying for an exam or competing in the Olympic Games, can build stronger circuitry and a more resilient brain. But acute, prolonged stress can wreak havoc.
So scientists are now actually finding specific evidence—and understanding the exact mechanisms at work—of how chronic stress can actually damage brain. We’d all like to avoid that, I’m sure. Of course, chronic stress can also cause high blood pressure, which leads to strokes, also damaging—sometimes very seriously—the brain. In fact, my father suffered in the later part of his life from stroke-related dementia, so I’ve seen it up close.
If you haven’t already incorporated some yoga stress management techniques into your daily life, take a look at one of my early posts The Relaxation Response and Yoga, which gives an overview of the many options that yoga provides. There are so many choices you’re sure to find something you enjoy and that you can practice on a regular basis.
P.S. After my post on Of Mice and Men, are you wondering how the scientists stressed out their test subjects? According to the LA Times, the researchers stressed out the mice by either immobilizing them in a straitjacket for three hours a day, seven days a week, or injecting them with corticosterone. Tiny straightjackets for mice? I’m not so sure what I think of that.
