The study of the human brain is growing more
sophisticated with the advent of more advanced
neuroimaging technologies. This development—
colliding with the aging of the baby boomers—
is driving the evolution of a new area of study
and practice: brain health.

The study of the human brain is simultaneously mysterious and fulfilling as we continue to learn more about its grand architecture
and function. This wonderful two-to-four-pound
structure is the single greatest and most complicated system ever designed in the history of the
universe. All of our thoughts, emotions, and
movements are products of thousands of neurons firing in response to a particular environmental input. Our brain is the birthplace of our
identity, and while we should strive to learn
everything we can about this part of our being,
we can only speculate about and imagine the
brain’s capabilities.
Despite our primitive understanding of
how the brain functions, we are now better
informed—and neuroscience has unleashed
findings both transforming and exciting. The
study of the human brain may be that final great
frontier of exploration that yields answers to our
most complex questions.
Excitement about human brain study has
accelerated with the advent of more advanced
neuroimaging technologies, and this is colliding
with the aging of the baby boomers (a cohort of
seventy-six million strong born between 1946
and 1964), a generation that is passionate and
educated about health. What has now evolved is
a new area of study and practice known as brain
health, one of the most popular and discussed
topics in healthcare today.
It is quite common to read about brain health
in consumer magazines and major newspapers, or
to see programs about it on television. The topic
has permeated the business sector, healthcare and
the insurance industry, assisted living, libraries,
lifelong learning institutes and education, the
media, and religion. While such information
dissemination is likely positive for educating the
general public, there remains a need to define
brain health and to rely on scientifically based
standards for consumer application.

Underlying the increased attention to the
human brain and brain health is a fundamental
question: Can the human brain be shaped for
health and, if so, how does this occur? Another
question of equal importance ponders what we
can do, if anything, to promote our brain health.
This issue of Generations addresses these
questions by providing a critical review of some
of the major areas of brain health. The purpose
of this issue is multifold: to discuss neural
plasticity as a primary mechanism for shaping
the brain towards health; to review both the
normal changes and pathologic conditions
associated with the aging brain (plasticity infers
both positive and negative change); to review
research on the relationship between lifestyle
and brain health; and to serve as a reference
point for the consumer to make informed
decisions about the ever-proliferating information on brain health.
Brain Health Defined
There is no uniform definition of brain health;
terms such as “brain fitness,” “cognitive fitness,”
and “mental fitness” are often used to mean the
same thing. While the contents of this Generations are not meant to be the ultimate standard
for defining brain health, it is important and
useful to put forth a definition that applies
especially to this issue of the journal.
Brain health is the result of a dynamic
process in which a person engages in behaviors
and environments to shape the brain toward a
healthier existence. The articles that follow
support the idea that environmental input (our
choice of actions and external stimuli) has an
impact on our brain. The focus is to try and
identify those behaviors and environments that
help to shape the brain toward health. Several
useful reviews have been published on the
relationship between environment and the
shaping of the brain towards health (Diamond
and Hopson, 1998; Kotulak, 1997; Nussbaum,
2003), and this Generations will build upon
these early reviews.
Brain health is also distinguished from
brain fitness and other similar terms for
purposes of this issue; it is presented as more
comprehensive in scope and considers environmental input and effects that extend beyond
cognition. While cognition is important, the
brain is more than a cognitive system; health
must include the emotional, spiritual, nutritional, social, and physical aspects that can
affect the brain. Brain fitness refers to a more
specific shaping of cognition. Today, brain
fitness typically refers to online software
programs that offer mental exercises.
Neurophysiology of Brain Health
There needs to be an underlying neurophysiological basis or explanation for a brain that
can be shaped. Neural plasticity offers such
an underlying explanation for brain health.
Plasticity is not a new concept. Donald Hebb,
who is sometimes referred to as the pioneer of
plasticity at the cellular level, presented a
theory in the middle part of the twentieth century that learning occurs based
upon the capacity of the neuron to be
strengthened, changed, or associated
with other cells from repeated activation. This is thought to represent the
foundation for a model of plasticity in the
central nervous system (Spatz, 1996).
For our purposes, neural plasticity shall refer
to a brain that is dynamic, constantly reorganizing, and malleable. This contrasts with some
traditional ideas of the human brain as a fixed,
rigid—and even degenerative—system from early
age. Neuroscience and psychosocial research
have demonstrated continued development of
the brain across the lifespan, supporting the idea
for plasticity at all ages (see the articles by Perls,

Patterson and Perlstein, and Wilson on pages 21,
27, and 58, respectively). A brain that is dynamic
and malleable can be shaped towards health.
Related to the work on neural plasticity has
been the emergence of the theory of brain
reserve (Katzman, 1995; Albert, 1995). Brain
reserve (sometimes referred to as intellectual
reserve, cognitive reserve, and synaptic density)
describes the brain’s development of neuronal
connections (neuronal changes) and related
knowledge or intelligence in response to particular
environmental input across the lifespan.
There is theory that brain reserve (Albert,
1995; Wilson et al., 2010) helps to delay onset of
neurodegenerative diseases such as Alzheimer’s
and related dementias (see Weirenga and Bondi
article on page 37). Much of this work has been
correlational in nature, but the literature is
relatively robust in showing behavioral and
neuroanatomical effects associated with environmental input (Moceri et al., 2000; Sapolsky,
1998; Snowdon, 2001; Stern et al., 1994). Brain
reserve theory explains how a brain with
plasticity is shaped toward health by environmental input. The important point to keep in
mind while reading this issue of Generations is
that the human brain has plasticity and this
plasticity enables the brain to be healthier
through mechanisms of brain reserve.
One major example of plasticity (and perhaps
brain reserve) is the finding that the human
brain can generate new brain cells (neurogenesis) (Eriksson et al., 1998). These authors
provided evidence for neurogenesis in the
dentate gyrus of the hippocampus of the human
brain, the same region found to demonstrate
neurogenesis in animal models (Diamond and
Hopson, 1998). While other reports support
neurogenesis in the human brain (Beck, 2000;
Roy et al., 2000), questions remain regarding the
functional or biological significance of neurogenesis in the adult human brain.
The following are logical questions to ask:
What leads to neurogenesis in the hippocampus of the human brain? Does neurogenesis
occur in other parts of the brain? The literature on the relationship between
enriched environments and the brains
of rodents (Diamond and Hopson,
1998) may help find answers to these
questions. Diamond’s work demonstrated that socialization, physical
activity, and mental stimulation are
important parts of an enriched environment
and she reported that rodents raised in enriched environments evinced healthier brains
at autopsy (larger cortex and neurogenesis in
the hippocampus) compared to rodents raised
in isolation.
In order to better understand what the
research teaches us about particular impacts
on the human brain, this issue’s articles will
expand on the findings of the enriched
environment, and review five major parts—
socialization, physical activity, mental stimulation, nutrition, and spirituality—of what I
call a “comprehensive brain health lifestyle”
(Nussbaum, 2010).
Novelty and Complexity
In my own study of and work on brain health
and lifestyle I have described the importance of
stimuli that are “novel and complex.” This is akin
to Diamond’s ideas on the importance of enriched
environments for shaping the brain. When the
brain is engaged with stimuli that are novel and
complex, the cortex is called upon to process at a
deeper level relative to overlearned information,
and this is potentially a critical factor in development of brain reserve. An example of an activity
that is novel and complex is one in which a
person has little ability, minimal or no experience
with the task, and will feel uncomfortable trying

Public Perceptions of Brain Health
In 2006, I served on a panel of experts to review and discuss survey data on the Attitudes and
Awareness of Brain Health (American Society on Aging, 2006). Commissioned by the American
Society on Aging and MetLife Foundation, surveyors telephoned 1,000 Americans and gathered data
that reflected the rapid emergence of brain health as an area of study and practice by the general
consumer. Data were weighted so that findings from the sample were projected for the national
population, ages 42 and older. A profile of the respondents is as follows:
• 75 percent of interviews were conducted with people below age 65, including nearly
50 percent with members of the aging baby boom generation;
• 66 percent report they work full time or part time, or are active as volunteers; 33 percent
are retired;
• 25 percent describe themselves as belonging to a racial or ethnic minority group;
• Among those who reported household income information, 20 percent are below $25,000
annually; 21 percent are between $25,000 and $49,000; 28 percent have from $50,000 to
$99,000; and the remaining 18 percent more than $100,000;
• 25 percent have some college or technical/vocational education; 28 percent report earning
college degrees; 40 percent are high school graduates or have completed a GED program; and
7 percent did not complete high school;
• Sample balanced by gender (53 percent female and 47 percent male), geographic region
(East, 26 percent; South, 26 percent; Midwest, 24 percent; and West, 24 percent); and
involvement in religious activity (51 percent “yes” and 49 percent “no”).
The survey yielded tremendous amounts of data regarding the public’s perceptions of brain health and
some of the major findings are as follows:
1. We are optimistic about brain health.
Nearly nine out of ten people think that it is possible to improve brain fitness.
• 53 percent believe it can improve a lot
• 35 percent believe it can improve a little
And: An overwhelming majority says that thinking abilities should be checked routinely, just like
a physical checkup.
• 59 percent say it is very important to get a checkup
• 32 percent say a checkup is somewhat important
But: Brain health is a low priority compared to other health issues.
• 3 percent rate it the most important health subject for people their age
• 7 percent consider it the second most important topic
2. Our memory is good today, but we have doubts about tomorrow.
We give ourselves high scores on our current brain fitness, regardless of age.
• 34 percent rate their current memory as excellent
• 62 percent rate their current memory as good

But: The younger we are, the sooner we anticipate that most people will begin to worry about
their memory.
• People ages 42 to 49 perceive that worries begin at age 52
• People ages 50-plus identify age 59 as the time when worries begin
3. We know about activities that are good for brain health.
Most people recognize that many activities are very useful for improving mental fitness.
At least 60 percent say to avoid tobacco, eat fresh fruits and vegetables, do puzzles, reduce
stress, limit alcoholic drinks, spend time with family and friends, and see the doctor regularly.
And: 84 percent report they spend time, usually daily, in activities that are good for brain health.
• 68 percent choose some kind of art or creative project, including 48 percent who spend
time reading
• 44 percent keep physically active
• 35 percent play games and do puzzles
• 25 percent work
• 22 percent spend time with others
4. Doctors are our preferred source for information about brain fitness.
More than 70 percent think that most people their age would go to a medical professional
to find out about the brain and how to keep it fit.
• 76 percent of women and 68 percent of men identify doctors as the best resource
for information
• People in their 40s and 50s are more likely than those ages 65-plus to choose the
Internet for brain health news
And: We encourage others who are concerned about their memory to see a doctor.
• More than 74 percent would advise close friends or family to talk to a doctor
But: We do not do what we think is best.
• Only 58 percent say they have talked about their memory or brain fitness with anyone
• 47 percent talk with family and 42 percent turn to friends
• Just 37 percent speak with a medical professional: 13 percent with a nurse and only
24 percent with a doctor
The panel of experts who reviewed the survey results offered the following major directives for the
nation: It is time to make brain health a national priority; it is time to apply the good news from brain
research; and brain fitness activities should be everywhere.

to complete it. We all have activities or tasks that
are new and hard for us. In contrast, an overlearned activity may also be considered a talent,
or more of a habit in which we do not utilize
much conscious processing to complete it: we
have tremendous ability and extensive experience
with it and we feel comfortable doing the task.
Over time, non-enriched environments that are
absent of socialization, limited with physical
activity, and without mental stimulation can have
a detrimental effect on the human brain (Moceri
et al., 2000), and stimuli characterized as passive
and rote, rather than novel and complex, may also
be detrimental (Friedland et al., 2001).
Brain health is a lifelong and proactive
process, one in which the brain is shaped by
environmental input. Environments that are
enriched and include socialization, physical
activity, mental stimulation, proper nutrition,
and spirituality can be beneficial to the brain. It

may be that the brain’s lifelong processing of
novel and complex stimuli that fosters development of brain reserve can yield a brain that is not
only healthier, but more capable of delaying the
onset of degenerative disease.
Brain Health: Moving Forward
The survey overview on pages nine and ten
provides a small window into the public’s
perception of brain health as recently as 2006.
Data suggest we are a nation interested and
informed to some degree about brain health,
but we do not yet prioritize the practice of
brain health as we should. We tend not to
follow our own advice for brain health, such as
talking to our doctors about our brain function.
The panel of experts concluded brain health
should be considered a national priority,
particularly given the impending explosion of
dementia. We remain a nation and world that
are more reactive than proactive with our
health and lifestyle. The panel also encouraged
application of research findings from study of
the human brain and lifestyle to our daily lives,
a process that has only just begun.
In the five years since the survey was published, we are now more educated about the
brain and brain health. However, I believe we
have much to do to educate everybody about
their brain and the behaviors that are part of a
proactive “brain health lifestyle.” We also need
to offer guidelines to better equip consumers
with information on all the programs, services,
and products that purport to be “brain healthy”
(see Fernandez article on page 63).
As excited and passionate as I am and my
colleagues are about teaching the general public
about the human brain and the research-based
behaviors thought to correlate with brain health
(especially reduction in risk of dementia), it
is vital to recognize concerns that have been
raised about the study and field of brain health.
Research on the impact of brain fitness (such as
cognitive software programs) has offered some
promise with improving self-reported and
performance-based measures of daily function
and cognitive abilities (Willis et al., 2006), but
others argue for a lack of empirical support for
general improvement in cognitive function
(Owen et al., 2010).
Similarly, while there is solid literature on
the relationship between lifestyle and aspects of
brain health across the lifespan (see Nussbaum,
2003, and other articles in this issue), others
raise concerns about the association of modifiable risk factors with cognitive decline or
Alzheimer’s Disease and the need for studies that
move beyond correlational findings (Daviglus
et al., 2010). One important consideration
regarding these two divergent viewpoints is the
idea that health promotion may be something
very different from disease prevention. Applying
ideas such as intervention and cure may not be
appropriate for the practice of health promotion.
Diverse viewpoints should be considered a
positive part of discovery and will only enhance
our understanding of the human brain and
brain health. However, the following ideas
about the brain and health, though not yet
conclusive, are gradually becoming more
accepted: the human brain has plasticity;
environmental input can shape the function
and structure of the brain; the human brain
continues to develop and express in late life;
brain reserve may delay onset of neurodegenerative disease; neurogenesis occurs in the
hippocampus of the human brain; and lifestyle
has a role in promotion of brain health.
These ideas offer hope for the emergence of
a more refined understanding of the human
brain. We must continue to educate the general
public about the basics of the brain and brain
function, and use the latest research findings to
help consumers apply this information to their
Brain health is a lifelong and proactive
process, one in which the brain is
shaped by environmental input.

daily lifestyle. To that end, we should conduct
well-controlled, double-blind studies to move
our understanding from the relational to the
causal. We also need to critically review our
progress and continue to apply research findings
to the practice of brain health.
I am delighted to serve as guest editor for
this issue of Generations. We are fortunate to
have some of the leading scholars, scientists,
clinicians, and business minds in the arena of
brain health to provide a state-of-the-art review.
Relying on the neurophysiological principles
described earlier, we offer here a broad approach
to brain health that integrates the critical
components of neuroscience, clinical practice,
and consumer application.
Guest Editor Paul D. Nussbaum, Ph.D., is a clinical
neuropsychologist and adjunct professor of Neurological Surgery at University of Pittsburgh School
of Medicine.
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