Brain Drains and Sprains

Until fairly recently, conventional wisdom among medical researchers probing the mysteries of the brain was that that glob of gray matter pretty much hits its growth peak at early adulthood, cannot create new functioning cells and deteriorates with disease and old age. Hey, stupid older person, live with your regressive cranial cavity! Not exactly. Myth exploded. The human brain has remarkable resiliency, expands its cellular structure to meet challenges, exhibiting a degree of plasticity that had scientists wowed by the flexibility of that incredible organ.

But in the world of “use it or lose it,” where obesity and sedentary lifestyles take their toll on muscle tone and longevity, comes another harsh lesson for too many of us. Sitting around watching TV, working at a sedentary job and living an inactive life takes its toll not just on the body but the brain itself. And then that lethargic brain then dictates some nasty commands to other parts of your body… seriously important parts.

Yup, brain fans, there’s some serious evidence that couch potatoes are yearning and striving for potato-like brains. The unfortunate rats that have paved the way for that understanding lived at Wayne State. “So for a study recently published in The Journal of Comparative Neurology, scientists at Wayne State University School of Medicine and other institutions gathered a dozen rats. They settled half of them in cages with running wheels and let the animals run at will. Rats like running, and these animals were soon covering about three miles a day on their wheels… The other rats were housed in cages without wheels and remained sedentary.

“After almost three months of resting or running, the animals were injected with a special dye that colors certain neurons in the brain. In this case, the scientists wanted to mark neurons in the animals’ rostral ventrolateral medulla, an obscure portion of the brain that controls breathing and other unconscious activities central to our existence.

“The rostral ventrolateral medulla commands the body’s sympathetic nervous system, which among other things controls blood pressure on a minute-by-minute basis by altering blood-vessel constriction. Although most of the science related to the rostral ventrolateral medulla has been completed using animals, imaging studies in people suggest that we have the same brain region and it functions similarly…

“And, as it turned out, when the scientists looked inside the brains of their rats after the animals had been active or sedentary for about 12 weeks, they found noticeable differences between the two groups in the shape of some of the neurons in that region of the brain… Using a computerized digitizing program to recreate the inside of the animals’ brains, the scientists established that the neurons in the brains of the running rats were still shaped much as they had been at the start of the study and were functioning normally… But many of the neurons in the brains of the sedentary rats had sprouted far more new tentacle-like arms known as branches. Branches connect healthy neurons into the nervous system. But these neurons now had more branches than normal neurons would have, making them more sensitive to stimuli and apt to zap scattershot messages into the nervous system…

“In effect, these neurons [from sedentary rats] had changed in ways that made them likely to overstimulate the sympathetic nervous system, potentially increasing blood pressure and contributing to the development of heart disease… This finding is important because it adds to our understanding of how, at a cellular level, inactivity increases the risk of heart disease, Dr. [Patrick Mueller, an associate professor of physiology at Wayne State] said. But even more intriguing, the results underscore that inactivity can change the structure and functioning of the brain, just as activity does.

“Of course, rats are not people, and this is a small, short-term study. But already one takeaway is that not moving has wide-ranging physiological effects. In upcoming presentations, Dr. Mueller said, he plans to show slides of the different rat neurons and, echoing the old anti-drug message, point out that ‘this is your brain. And this is your brain on the couch.’” New York Times, January 22^nd. A couch trip probably won’t get you too far, I guess.

I’m Peter Dekom, and remember that New Year’s resolution about hitting the gym more often…..