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sound you know where to look).
formation from the cortex and organizes it into memories. The
These hundreds of regions are linked together by the
wiring of the cortex and hippocampus is designed to form links
brains equivalent of wires: thin threads called axons (each only
(or associations) between different sensory representations of
one hundredth the thickness of a human hair) that extend
the same object, event, or behavior.


with information, some of it vital but much of it unimportant.
There are 30 spe-
from nerve cells and You don't need to remember the face of everyone you pass on
cialized areas in
conduct electrical im- the visual cortex the street, but you do want to recognize someone you just met
alone; each area
pulses from one part of at your boss's party! To prevent the information overload that
links up (commu-
the brain to another. would accompany having to remember too much, the hip-
nicates) with its
neighbors (shown
Every cortical region pocampus sifts through the barrage of incoming information
here in simplified
sends and receives mil- from the cortex and picks out what to store or discard. In other
form). A realistic
diagram would
lions of impulses via words, the hippocampus acts like a central clearinghouse, de-
show over 200
these axons to and from ciding what will be placed into long-term memory, and then,
dozens of other cortical when called upon, retrieving it. The hippocampus's decision to
regions. The brain con- store a memory is believed to hinge on two factors: whether
tains literally hundreds the information has emotional significance, or whether it re-
of miles of such wires. lates to something we already know.
Thus, the cortex resem- The hippocampus is also vital for making mental maps,
bles an intricate web, VISUAL AREAS OF THE CORTEX allowing us to remember things like where our car is parked
with each region linked directly or indirectly or how to get from home to work. Animals in which the hip-
to many other regions. Some of these connections are between pocampus has been removed cannot learn or remember
areas that process similar information, such as the thirty in- simple mazes.
volving vision, while other connections are between dissimilar Most problems that cause mental deficiencies involve the
areas, such as touch and smell. The network of pathways be- cerebral cortex or the hippocampus. So keeping mentally fit re-
tween cortical regions that do many different things is what ally means exercising these parts of our brain so they function
allows the cortex to be so adept at forming associations. at their best. And what they do best is to form associations be-
Like the cortex, the hippocampus plays an important role tween different kinds of information they receive.
in forming associations. The senses continually flood the brain

ASSOCIATIONS: How WE LEARN mans and animals can form similar links between almost any
kind of sensory inputs.
Associations are representations of events, people, and places
Obviously, humans are capable of much more sophisticated
that form when the brain decides to link different kinds of in-
and abstract learning that isn't as closely tied to external stimuli
formation, especially if the link is likely to be useful in the fu-
(like bells) or external rewards (like food). Take learning a lan-
ture. The raw material for associations originates primarily
guage, for example. An infant learns language by associating a
from the five senses but also can be emotional or social cues.
particular set of sounds with a certain behavior, person, or ob-
The brain takes several different things into account in decid-
ject. (An explicit reward may or may not be present.)
ing whether to forge these mental connections. For example, if
Once such associations are formed, they reside in the
something provides inputs to two or more senses close to-
brain as a long-term memory, which can be accessed just by
gether in time, like the sight, smell, and taste of a cheese-
experiencing the original stimulus. It's rather astounding
burger, the brain will almost automatically link the sensations.
when you think about it: A certain kind of sensory experience
In essence, this is our basic learning process.
can permanently change the wiring in part of your brain!
The classic example of associative linking, often taught in
Most of what we learn and remember relies on the ability
introductory psychology courses, is Dr. Ivan Pavlov's experi-
of the brain to form and retrieve associations in much the
ments with dogs. Dogs normally salivate at the sight of food.
same way as Pavlov's dogs learned that a bell meant food. For
Every day when Pavlov fed the dogs, he rang a bell. After a
example, you pick up a rose, and its smell activates the olfactory
few days, just ringing a bell made the dogs salivate, even if no
(smelling) parts of the cortex, its image activates the visual
food was presented.
areas, and the soft petals or sharp thorns activate the feeling
These dogs made an association”a connection within
sections. All these different sensations cause nerve cells in
their brains”that a certain sensory stimulus (the bell) meant
very different areas of the cortex to be activated at the same
food. Consequently, the sound of the bell alone made the
time in a particular pattern, strengthening some of the link-
brain instruct the salivary glands to get ready for food. Hu-
ages between these areas.

14 15

Once that happens, anything that activates just part of the
network will activate all the areas of the brain that have repre-
Existing programs for brain exercise have ignored this power-
sentations of rose events. Someone hands you a rose, and as you
ful associative route to forming and retrieving memories.
hold it, you may remember your first wedding anniversary
Neurobics seeks to access it by providing the cortex with the
when you received a dozen roses, which reminds you of your
raw material that will create new and potent associations.
first apartment in that awful building with the broken elevator.
Because each memory is represented in many different cor-
Or the smell of roses reminds you of Aunt Harriet's rose garden
tical areas, the stronger and richer the network of associations
in late summer where you had picnics with your cousin Arnie
or representations you have built into your brain, the more your
who is now living in California and whom you keep meaning to
brain is protected from the loss of any one representation.1
call”all sorts of memories result from a single stimulus.
Take the common problem of remembering names.
When you meet a new person, your brain links a name to a
K you just see a rose, you activate only a small number of neural few sensory inputs, such as his appearance (visual). When the
pathways (bold arrows, left segment) within the visual cortex.
brain is younger, these few associations are strong enough so
that the next time you see this person, you recall his name.
But the more you age, the more people you've met, leaving
fewer unique visual characteristics available to represent each
new person, so the associative links between visual character-
istics and names are more tenuous. Now, imagine closing
your eyes in the course of meeting someone. Sensory inputs,
other than vision, become much more important as the basis
for forming associations necessary for recalling a name: the
But if you smell, touch, and see a rose, a much larger number of direct and indirect
pathways between the olfactory, visual, and tactile areas are activated (above, right feel of his hand, his smell, the quality of his voice.
segment). These associative linkages between senses help in memory recall.

16 17

These multisensory representations for tasks like remem-
Neurobic First Meeting
Ordinary First Meeting
bering names were always available to you, but early on, your
brain established an effective routine for meeting people that
relied primarily on visual cues. An important part of the Neu-
robic strategy is to help you "see" in other ways”to use other
senses to increase the number and range of associations you
make. The larger your "safety net," the better your chances of
solving a problem or meeting a challenge because you simply
have more pathways available to reach a conclusion.
Name Recall: If you use only sight when you meet someone, you're less likely to remem-
More often than not, adults don't exploit the brain's rich po-
ber his name. If, on the other hand, you use all your senses, you'll have many more as-
tential for multisensory associations. Think of a baby encoun-
soclations-'thinnlng hair, middle-aged, glasses, hand feels like a damp, limp rag,
clothes smell like a smokehouse, voice sounds like a bullfrog"-to recall his name.
tering a rattle. She'll look at it closely, pick it up, and run her
fingers around it, shake it, listen to whether it makes a sound,
You have now tagged someone's name with not just one or
and then most likely stick it in her mouth to taste and feel it
two associations, but at least four. If access to one associative
with her tongue and lips. The child's rapidly growing brain uses
pathway is partly blocked ("Gosh, he looks familiar"), you can
all of her senses to develop the network of associations that will
tap into associations based on other senses and do an end run
become her memory of a rattle.
around the obstruction. Adopting the strategies of forming
Now think of yourself finding a rattle on the floor.
multisensory associations when the brain is still at or near its
Most likely, you'll just look at it and instantly catalog it:
peak performance”in the forties and fifties”builds a bulwark
"It's a rattle." The point is that a child is constantly tapping
against some of the inevitable loss of processing power later in
into the brain's ability to strengthen and increase connections
life. If your network of associations is very large, it's like hav-
between its many regions”for smelling, touching, hearing,
ing a very tightly woven net, and the loss of a few threads isn't
tasting, and seeing”to produce an ever-growing tapestry
going to let much fall through.


ferent are your commutes, your breakfasts, lunches, and din-
of associations...and neural activity.
ners, week in and week out? And what about things like shop-
Adults miss out on this multisen-
ping and laundry? It's startling to realize just how predictable
sory experience of new associations
and free from surprises our everyday lives really are and, as a
and sensory involvement because we
consequence, how little we tap into our brain's ability to make
tend to rely heavily on only one or two
new associations.
senses. As we grow older, we find that
Now, routines are not necessarily bad. People created rou-
life is easier and less stressful when
tines because until recent times, the world was unpredictable,
it's predictable. So we tend to avoid
and finding food and shelter was filled with risk and
new experiences and develop routines Simultaneous sensory
input creates a neural danger. Once reliable sources of food, water, and shelter were
around what we already know and feel "safety net" that traps
discovered, it made sense to continue in the same patterns
comfortable with. By doing this, we information for future
that allowed them to be obtained with a minimum of risk.
reduce opportunities for making new access.
associations to a level that is less than ideal for brain fitness. Discovering and practicing successful routines in an
unpredictable world ensured survival.
But in our late-twentieth-century, middle-class American
ROUTINES CAN BE BRAIN-DEADENING lives, such unpredictability is largely gone. Food is readily
available at the local supermarket; water flows from the tap;
You may be reading this and thinking, "I lead a fairly active
weather-resistant, heated and cooled houses shrug off the cli-
life and my brain seems pretty stimulated. Sure, I have my
mate. Modern medicines ward off most common diseases.
routines, but it's not like I don't see new movies, listen to new
We even count on the fact that our favorite TV shows air
songs on the radio, watch TV, or meet new people."
each week at the same time.2
The truth, however, is that most of us go through our adult
What consequences does this predictability have on the
lives engaged in a series of remarkably fixed routines. Think
brain? Because routine behaviors are almost subconscious,
about your average week.. .or day-to-day life. Really, how dif-


First Exposure Routine Novel
they are carried out using a minimum of brain energy”and
provide little brain exercise. The power of the cortex to form
new associations is vastly underutilized.
If you drive or walk to work via the same route every day,
you use the same brain pathways. The neural links between
brain areas required to perform that trip become strong. But
other links to areas that were initially activated when the
route was novel”such as a new smell, sight, or sound when
you rounded a certain corner”get weaker as the trip be-
comes routine. So you become very efficient at getting from
point A to point B, but at a cost to the brain. You lose out on
PET scans of three vertical slices of the brain show that significantly more path-
opportunities for novelty and the kind of diverse, multisen-
ways are activated (shown in cross-hatching) when the brain processes a Novel
sory associations that give the brain a good workout. task than when it performs a Routine one. During the routine task (middle column)
there is no increased activity in the anterior cortex, cerebellum, or frontal cortex.

THE BRAIN HUNGERS FOR NOVELTY But if it is simply more activity in the brain that leads to in-
creased neurotrophin production, then listening to more music
The human brain is evolutionarily primed to seek out and re-
(even noise), or watching more TV, or getting a massage”all of
spond to what is unexpected or novel”new information com-
which stimulate the sense organs”would lead to better brain
ing in from the outside world that is different from what it
health. Such passive stimulation of the senses, however, doesn't
expects. It's what turns the brain on. In response to novelty, cor-
tical activity is increased in more and varied brain areas.3 This work as a brain exercise and neither does repeatedly doing the
same routine activities. Neurobics is neither passive nor routine.
strengthens synaptic connections, links different areas together
It uses the senses in novel ways to break out of everyday routines.
in new patterns, and pumps up production of neurotrophins.

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OUR UNDERUSED SENSES far more relevant than they are today. A keen sense of smell
was often vital to survival. Native Americans could track ani-
Our five senses are the portals, or gateways, through which
mals by their smell; farmers could smell when a change in the
the brain gets its entire contact with the outside world. We
weather was about to happen; smell was important in making
rely primarily on our senses of vision and hearing because
sure that foods were safe to eat; doctors even used their sense
they quickly tell us a lot about our environment. Our other
of smell to diagnose illness. Today, unless you have a very spe-
senses”smell, taste, and touch”are less frequently and obvi-
cial job, such as creating perfumes, aromas usually function as
ously called upon. To understand this better, close your eyes
masks (that's why we use deodorants and fragrances).
and try walking through a room. Instantly, the world around
Despite its diminished role in our daily lives, however, the
you changes radically. Sounds, smells, and spatial memories
sense of smell plays an important role in memory. Associations
of your physical surroundings leap into consciousness. With
based on odors form rapidly and persist for a very long time,
vision gone, your sense of touch suddenly becomes para-
unlike those based on the other
mount. Navigating even a familiar environment is a real chal-
senses. The olfactory system is the
lenge, and your brain goes into high alert.
only sense that has direct connec-
The brain has a huge network of pathways based on visual
tions to the cortex, hippocampus,
information. That's why so many everyday experiences are
and other parts of the limbic sys-
geared to visual appeal. In magazine, television, and billboard
tem involved in processing emo-
ads, businesses use visual associations to encourage purchasing
tions and storing memories (see
decisions. In a world increasingly dominated by shrink-
illustration, page 10). That's why
wrapped, plastic-packaged, and deodorized items, the efforts
certain aromas like fresh-baked
demanded of our other senses, such as touch and smell, are
bread or a particular flower, spice,
diminished”far more than we're consciously aware of.
or perfume can trigger an abun-
Information and associations based on smell used to be
dance of emotional responses that


If, magically, there were a drug to increase mental per-
Progress in neuroscience research has also led to promising
Mrnance, it would do no good unless you were exercising
drugs for treating serious brain ailments like Alzheimer's
brain at the same time. It would be like drinking one of
and Parkinson's diseases. But an unfortunate by-product of
|ifaose high-protein boosters and then not doing any physi-
this progress in a society oriented to a "pill for every ill" is a
. exercise.
growing demand for medications, pills, or diet supple-
There are also claims that brain performance can be
ments that will either magically halt declines in mental
lanced or preserved by taking large amounts of certain
abilities or improve performance with a quick fix.
iturally occurring vitamins, minerals, or plant extracts,
The media perennially tout the promise of new memory-
lile there is no question that a well-balanced diet and
enhancing pills with advertisements for "smart drugs."
physical exercise are important for maintaining a healthy
There are, in fact, drugs that do increase the synaptic
JpMrain, there is no clear scientific evidence to support the
transmission in the brain in various ways, and some of
Ijclaimed memory benefits of specific dietary supplements.
these may provide short-term memory enhancements. The
We believe a more prudent route to brain health is to
problem is that there are always hidden and still unknown
planless the brain's ability to manufacture its own natural nu-
risks in using such drugs. (Remember the negative side ef-
strients. With this approach, neurotrophins and similar mol-
fects on athletes who took steroids to boost physical per-
fecules wUl be produced in the right places, and in the right
formance?) Furthermore, the effects of "smart drugs" are
lamounts, without side effects.
only short term, so they have to be taken continuously.


stimulate the memory of events associated with them. (For ex-
As we age, our social circles tend to shrink, so an important as-
ample, realtors often advise you to have something delicious
pect of Neurobic exercise is to find opportunities to interact
baking in the oven when you're showing your house for sale.
with others. Not only does this engage our interest, which di-
And if you saw Scent of a Woman, you'll remember how Al Pa-
rectly helps us to remember things, but as the MacArthur
cino's blind character could call up complex associations based
Foundation's studies on aging have clearly demonstrated, so-

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