http://journal.frontiersin.org/article/10.3389/fpsyg.2016.01118/full?
Joyce Shaffer- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA, USA
Introduction
Since 2011, our Director of NIMH has encouraged “the
21st century discipline of clinical neuroscience” to include
brain-plasticity based strategies in providing clinical care (White, 2011).
Neuroplasticity, the capacity of brain cells to change in response to
intrinsic and extrinsic factors, can have negative or positive influence
at any age across the entire lifespan. How can these factors be
influenced in clinical settings? In keeping with the increasing shift in
focus from illness to what maximizes wellness, psychologists are
uniquely trained to use evidence based behavioral techniques as
effective methods for driving neuroplasticity in a positive direction.
Search efforts for this review were primarily focused
within the PubMed database using combinations of keywords listed above
as well as names of prominent researchers in the field. Also,
bibliographies of these articles and related reviews were searched.
Studies accepted for review included animal as well as human studies.
Studies reviewed met rigorous scientific standards, were almost
exclusively broad review articles or random controlled trials, and were
included without a specified time span. Periodic searches of this nature
were conducted between 2005 and 2016.
It has been estimated that dementia has been detected at the rate of one new person about every 7 s around the world (Ferri et al., 2005). Brookmeyer et al. (2007)
estimate that success in delaying the onset of dementia by as little as
a year could reduce the global burden of Alzheimer’s disease by as much
as 9,200,000 cases in 2050, a number that makes driving brain
plasticity in a positive direction a top priority worldwide.
The focus of this article is to review the scientific
foundation and recent progress in research of neuroplasticity; relate
that to the various ways these findings can influence treatment; propose
ways treatment protocols could increase adherence to brain plasticity
based therapeutics; and suggest research questions going forward. Before
proceeding on how to impact the so called “normal age-related cognitive
decline,” it is important to consider recent research on the myth of
cognitive decline (Ramscar et al., 2014).
While noting that there are changes in performance on many psychometric
tasks with aging, the results of this long series of studies indicate
that these changes reflect the “consequences of learning on information
processing, and not cognitive decline.” Across the years adults develop a
greater sensitivity to small details of differences in stimuli,
accumulate more acquired knowledge, and, as a result, have more and
different demands in their memory search “which escalate as experience
grows.” These researchers concluded that the performance of older adults
is a reflection of predictable outcomes of increased learning on
information processing and is not an indication of cognitive decline.
Viewing cognitive differences across the lifespan as related to better
awareness of details and accumulated learning is an example of a hopeful
perspective which could effectively empower any individual to factor
neuroplasticity into their efforts to promote improved business and
health behaviors.
Researchers have referred to Michael Merzenich as the
“father of plasticity” because he enjoyed a long career that established
that the human brain is highly plastic and that led Merzenich to
develop science-based novel interventions to drive improvements. Because
of her decades of research preceding that of Merzenich, let us consider
Marian Diamond to be the “mother of neuroplasticity.” Her work
influenced a paradigm shift for scientists when she was the first to
prove that the brain shrinks with impoverishment and grows in an
enriched environment at any age (Diamond et al., 1971, 1984; Malkasian and Diamond, 1971). Fred Gage brought science another paradigm shift with the proof of neurogenesis in humans (Eriksson et al., 1998); showing how animals could sustain fivefold induction of neurogenesis (Kempermann et al., 2002); demonstration of how humans can increase neurogenesis (Pereira et al., 2007); and using human induced pluripotent stem cells to model neurogenesis in the hippocampus (Yu et al., 2014). Richard Davidson’s research found that thought alone was associated with neuroplastic gains (Davidson and Lutz, 2008; Davidson and McEwen, 2012) and improved immune response (Davidson et al., 2003; Kaliman et al., 2014).
There is a growing corpus of literature on ways to drive
brain plasticity in a positive direction that could contribute more
powerfully in strategies of intervention for healing and enhancement of
function than would research on what drives loss. These findings coupled
with recent neuroscience clearly showing the potential for improving
brain plasticity (Goh and Park, 2009)
could give humans unprecedented hope for personal empowerment.
Neuroplasticity research has fleshed out what these chemical,
anatomical, and performance gains could include.
Healthcare providers including psychologists (Cramer et al., 2011) need to address all of the essentials identified by Diamond as well as other lifestyle choices such as sleep (Jacobs et al., 2004; Guzman-Marin and McGinty, 2006; Zhu et al., 2012; Castronovo et al., 2014; Irwin, 2014), reducing inflammation (Kohman and Rhodes, 2012; Rosano et al., 2012; Irwin, 2014) and turning stress into power (Sapolsky, 2004; Zucconi et al., 2006).
Psychology is uniquely positioned to maximize the “revolution which is
set to transform the diagnosis and treatment of mental illness and
reverse the lack of major progress made in curbing associated ill health
and death over the past 100 years” (White, 2011).
This specialty can influence “the development of a credible risk score
coupled with some, or all of, cognitive training, psychosocial
approaches, education, and the use of specially designed video and
computer games” as well as promoting choices that can enhance
neuroplasticity for, per Marian Diamond, “Enriching Heredity.”
Applying interventions in positive ways to enhance
neuroplasticity is the model proposed herein because it captures changes
made in the Diamond lab; the only change in their enriched environment
was having lab workers hold and talk with the rats; that “TLC” resulted
in fifty percent increase in longevity while maintaining plastic gains
even in animals that lived to the equivalent of ninety human years (Diamond et al., 1984).
Diamond opined these plastic gains could be enjoyed by humans at any
age. She identified five essentials for a healthy brain: newness,
challenge, exercise, diet, and love.
