Use It or Lose It
One of the most novel avenues of brain research has produced astonishing evidence that the way you use your brain can alter its very form. Stimulating your brain intellectually and physically can actually cause measurable changes in its structure. Such activity can prod the brain to produce new connections between neurons and even create brand-new brain cells! That’s what many scientists now say, based on very recent research. Unquestionably, it happens in laboratory rats, according to remarkable findings.
A research team headed by William T. Greenough, of the University of Illinois at Urbana-Champaign, raised rats in three different environments—alone in cages, two to a cage, and in a large playground cage with many young rats, toys, and treadmills—”a Disneyland for rats,” in Dr. Greenough’s words. He compared the complexity of their brain cells.
What he found was startling. Within only four days of exposure to the “Disney wonderland of fun and games” the rats’ brains went wild with new growth—the density of their synapses and the length of their dendrites increased profusely and rapidly. In short, the animals in the stimulating environment suddenly acquired more connections per nerve cell—more synapses—and a lush forest of dendrites.
Their brains also grew new blood vessels to transport more blood and oxygen required to feed the rats’ more active brain cells. Plus, the round bodies of the neurons grew bigger. Dr. Greenough put the rats through their paces in mazes and other tasks and found the stimulated rats per-formed better and were smarter.
Older rats put into the “rat wonderland also grew more new connections between brain cells, compared with those left to languish in a restricted, dull environment—”cage potatoes,” Dr. Greenough calls them. However, the brains of the old rats sprouted new connections more slowly than did the brains of young rats.
Dr. Greenough theorizes that the rats’ stimulating lifestyle switched on genes in nerve cells, producing proteins that spurred the new growth of dendrites and synapses. Also exciting are more recent studies by neuroscientist Fred Gage and colleagues at the Salk Institute for Biological Studies in La Jolla, California. They took newborn rats and put some in ordinary laboratory housing and others in an “enriched environment with climbing tubes and running wheels, novel food, and lots of social interaction.
Two months later, the “teenage rats were subjected to brain examination, using a tracer drug to pinpoint new brain cells. According to Dr. Gage, the researchers counted every cell in the hippocampus of both sets of rats. The rats who grew up in ordinary digs had 270,000 neurons on each hemisphere of the hippocampus. Incredibly, the rats who grew up in the rollicking fun-and-games environment had an extra 50,000 brain cells in each side of their hippocampus. Thus, the stimulating environment added nearly twenty percent more brain cells, strategically placed in the memory and learning center of their brains!
Other tests on stimulated mice showed essentially the same startling increase in number of neurons and branching dendrites. Moreover, mice that lived in a stimulating environment were smarter, performing better on water maze tests of memory and learning than mice housed in spartan surroundings. Scientists explain that some neurons typically form in the brains of animals after birth, but usually die quickly.
In the stimulated animals the newly formed cells mysteriously live on, increasing intellect. Janice Juraska, neuroscientist at the University of Illinois, calls such experiments “a unique demonstration of the power of the environment to sculpt the brain.” The implications for young children are mind-boggling.
Exercise Expands Brains
A few years ago scientists were blown away by experiments showing that putting rats on treadmills induced their brain cells to produce a chemical “growth factor’ that spurs growth of dendrites, thereby expanding communication networks. Most remarkable, the neuronal growth happened not only in parts of the brain that control motor function, but also in areas that control memory, reasoning, thinking, and learning, according to the research by Carl Cotman and colleagues at the University of California at Irvine.
Exercise also increased blood flow to the brain. Dr. Cotman later found that older humans who exercised scored higher on tests of cognitive function than non-exercisers.
Remarkable new findings by Arthur Kramer of the University of Illinois at Urbana-Champaign further prove how exercise infuses new life into the brain. Dr. Kramer tested the cognitive functioning of 124 men and women, ages sixty to seventy-five, who never or rarely exercised. He put them on a three-times-a-week regimen of either aerobic exercise—a brisk one-hour walk—or yoga-type stretching.
After six months, the walkers scored 25 percent higher than the stretchers on cognitive tests of “executive control” or “executive memory” The boost occurred in “higher” functions of decision-making, planning, scheduling, ability to quickly switch tasks, look up and remember phone numbers—skills essential for independent living, yet the first to decline as you get older. Dr. Kramer believes aerobic exercise pumps more blood to the brain’s frontal cortex that controls exec-utive functions.
Other researchers find that exercise raises levels of free-radical fighters to protect brain cells and that activity of any type improves mood.
“Simply running a few days a week increases brain proteins, and that helps protect nerve cells from injury, cells known to be associated with cognition.” — Carl Cotman, University of California at Irvine
Truly we have entered a new miracle age of the brain, bursting with the promise of unprecedented emotional and intellectual fulfillment. Scientists for the first time in history are beginning to comprehend the brain’s awesome “plasticity”—its stunning ability to continually reinvent itself. All of us alive today are the beneficiaries of this new knowledge.