Build a Better Brain
Learning, the process by which we acquire information about our
world, may actually change our brains for the better.
By Beth Livermore, published on September 1, 1992 - last reviewed on June 20, 2012
In one corner stands a stack of magazines. In another sits the Sunday paper. On the
counter, the radio crackles with news, while nearby the fax machine hums. The
information age is definitely upon us.
If you're like most, you're still reeling, struggling to take it all in, perhaps shutting down
your input channels entirely or jettisoning subscriptions simply to survive. And it's not
going to get any better. The outlook report from dataland is bleak: Every five years, the
information load is doubling.
There's nothing left to do but hope for a bigger, brighter brain.
What the data doctors can't even hope to promise, science may yet deliver. In this, the
Decade of the Brain, researchers are hot on the trail of how we acquire and store
information. Merging psychology with biology, they have made a series of recent
discoveries that appear to catch learning in its tracks.
Neuroscientists plumbing this virgin terrain now know that, along with genetic
inheritance, experience shapes the very structure of our nervous systems—it alters the
brain circuits that process everything from a French lesson to an auto repair guide.
Learning, the process by which we acquire information about our world, may actually
change our brains for the better. Animal research suggests that the more we use our
brains, the more efficient our intellectual muscle gets.
Taken together, their work demonstrates that the brain is an extraordinarily plastic
organ, responding actively to a novel environment by growing new connections to greet
it. Although the brain is unlike any other organ in that it lacks the ability for cell-body
renewal, nerve cells do generate new connections, or synapses—the points at which
signals are transmitted—forging new and enhanced pathways for the flow of
information.
These findings suggest you can essentially train your brain to collate more information
faster, and access it quicker and better. And under the right conditions of stimulation,
you can grow yourself a brain that will keep up with your information needs—perhaps
even exceed them.
Nature does set certain parameters. We all start out with about the same number of
neurons, or brain cells, having the same basic structure. By nine months of age, our
nerve cells stop dividing, leaving us with about 100 billion to a trillion each.
By far the most sophisticated thinking machine known to man, the adult brain massively
outperforms today's best supercomputer. It processes billions of operations a second—
approximately 10[15], versus a mere 109 for the machine—all in three pounds of tissue
crammed inside the cranium. So densely packed is the brain that a sample no larger
than a grain of rice contains one million neurons, 20 miles of axon—or the extension
cords of nerve cells—and 10 billion synapses, calculates California neurobiologist
Charles Stevens, Ph.D.
The vast majority of them are contained in the cerebral cortex, or neocortex, the most
recently evolved part of the brain—a highly corrugated sheet of gray matter less than
three eighths of an inch deep that overlies most other brain structures. The cortex
accounts for 80 percent of its total volume and containing the equipment responsible for
many sensations, thoughts, imagery, language, and other distinctively human abilities.
Here, with the assistance of other brain structures, is where the brain makes sense of
received stimuli, piecing together the signals from various sensory pathways,
connecting them and interconnecting them, and converting them into felt experience.
Formerly the domain of philosophers, this once-ethereal territory has been opened for
scientific exploration. Using such technological advances as electrodes, gels, highpowered microscopes and imaging devices including positron emission tomography, or
PET scans (think of them as maps of energy flow), along with such low-tech equipment
as sea slugs and rat brains, neuroscientists are providing an
unprecedented understandingof our brains.
"Stimulation in general is very important to the development of the brain," reports
neurobiologist Carla Shatz, Ph.D., of the University of California at Berkeley. While
evolution has programmed us to perform certain basic tasks necessary to sustain life—
such as eating and sleeping—we still have to learn how to do almost everything else.
Researchers believe that, from birth to adolescence, we are laying down the basic
circuitry of the brain. As we grow up, the world subsequently makes its mark physically.
Exposure to novel tasks and novel stimuli generates the development of new circuits
and synapses for handling all of them. From then on, continued stimulation throughout
life further strengthens these pathways and enhances their interconnections.
Scientists cannot yet quantify exactly how much an enriched environment helps the
brains of young children to grow. But "we do know that deprivation and isolation can
result in failure of the brain to form its rich set of connections," says Shatz.
Whether it's a new sensation or a fresh idea, every outside stimulus is first converted
into electrical signals as it enters the cranium. These electrical signals trundle down
known pathways, splitting off into multiple directions for processing. Where the lack of
prior experience has left no established route, the signal will forge a new one, linking
neuron to neuron as it travels along. The resulting chain is called a brain circuit, and the
next time the same stimulus enters the brain, it speeds efficiently along its old route,
now grooved into an expressway. Hundreds of millions of brain circuits are created by
millions of experiences…
..[T]he brain is an enormously adaptive organ: The connections between neurons
proliferate and shrink depending upon use. The links between them can be
strengthened or weakened. "Brain networks can always be fine-tuned," says
neurobiologist Stevens, of the Howard Hughes Medical Institute at Salk Institute in La
Jolla. The more synapses between cells, the more avenues for information
transmission. The better your cells communicate with one another, the more information
you can likely digest, understand and recall efficiently.
"Smarter" people—those who can consume and regurgitate facts with the efficiency of
machines—may in fact have a greater number of neural networks more intricately
woven together. And recall of any one part seems to summon up a whole web of
information.
Pictures of the brain in action confirm this model of efficiency of information flow.
Researchers scanning human brains by positron emission tomography (PET)—which
highlights the regions that work hardest during various tasks—found that "smarter"
brains consume less energy than other brains; to do the same tasks they require less
glucose, their favored fuel. "It maybe that once the brain becomes really well grooved
you don't need as much energy," explains Eric Kandel, M.D., a neurobiologist at the
Howard Hughes Medical Institute at Columbia University in New York.
Perhaps that explains why rats raised in enriched environments later learn faster than
counterparts kept in barren cages. And perhaps it will help researchers to understand a
recent controversial study showing a significant correlation between low levels
ofeducation and the incidence of Alzheimer's disease. According to neuroscientist
Robert Katzman, Ph.D., of the University of California at San Diego, individuals who
lack formal education may develop fewer synapses, or junctures between neurons, than
individuals who have routinely stretched their minds. Then, when disease occurs, there
is less brain reserve to call on, he says. When Alzheimer's disease strikes them, the
loss of synapses is dramatic and quick to show.
Katzman hopes to directly investigate whether the number of synapses in uneducated
people is actually different from that of educated people. In the meantime,
neurobiologist Richard Mayeux, Ph.D., of Columbia University, appears to have
confirmed part of what Katzman is getting at. He has shown that people with high IQs
can withstand more brain scarring than less gifted people before they show a noticeable
loss of intellect…
Background of Rosenzweig and Bennett:
Rosenzweig and Bennet’s study aims to understand the effects the
environment has on the structures of the brain. They specifically analyze
the effects the environment has on dendritic branching; which is a
physiological process. Dendritic branching occurs when the neurons in the
brain make new, and more connections between dendrites. This enables a
person to complete a task with greater ease, even if it was initially difficult.
Summary of the procedure:
Rosenzweig and Bennett began the experiment by placing a set of rats into
one of three environments. One was a neutral environment; which was a
standard cage for rats. The second was an enriched environment, which
had toys and obstacles for the rats to climb on. The third was a deprived
environment, which had the bare necessities for survival. Furthermore, in
the enriched environment, Rosenzweig and Bennett paced many rats,
while there was only one in the deprived environment.
After allowing the rats to stay in the environments for between 30 and 60
days, they killed the rats, and analyzed their brains.
Summary of findings and conclusions:
Upon analysis of the brains, the researchers discovered that the frontal
cortex of the rats in the enriched environments were denser, and had
more dendritic connections than those of the rats in the deprived
environments. The frontal cortex is responsible for planning, and problem
solving Rosenzweig and Bennett concluded that the enriched environment
allowed the rats opportunities to “learn” and “problem solve,” which
increased the amount of dendritic connections in that portion of the brain.
Name:_____________________________________
Block:_____________
Build a Better Brain Questions:
1. What does “brain plasticity” mean?
2. What is “dendritic branching?”
3. How can the environment affect the physiological process of dendritic branching?
4. How did the environment affect the rats in Rosenzewig and Bennett’s study?
5. Respond to the following question as an 8-mark. Use empirical evidence from class, the
article, and the study to support your answer.
How can the environment affect a physiological process?