By: H. Randall Griffith, Ph.D., ABPP
Ackerson and Associates, Birmingham Alabama
Most of the
questions I tend to get in my clinical practice regarding cognitive enhancement
have to do with memory functioning. However, memory is but the tip of the
iceberg for cognitive enhancement. In order to understand how we can change our
cognitive functioning, it is useful first to think about how the brain
processes information in general. The brain is a vast storage and communication
network comprised of around 100 billion neurons, which are the basic cells that
make up the brain, as well as some 100 trillion connections among these
neurons. Think of the internet, but on a vaster scale. Each neuron could
represent a networked device on the internet: it receives information from
thousands and thousands of other devices and can send out information to
thousands and thousands of others. The connections between neurons are called
synapses, and it is at these synapses where the dynamic processes of brain
functioning primarily occur.
Unlike in the world of the
internet, where everything comes through one cable or wireless connection, in
the brain the number of synapses are critically important for the functioning
of an efficient network. The brain is flexible in the way it makes these
connections, astonishingly so. Microscopic images of synapses that are
presented in a time sequence show these connections among neurons literally
blooming before the viewer's eye. Well-connected neurons can be widely
influential, and are able to become more efficient in their response to
receiving messages: they actually learn to respond more robustly to certain
signals from other “familiar” neurons. The bottom line is that the health of
neurons, their connections, and the biochemical processes that govern the
actions of these connections is critically important to how our brains function
(or do not function!) as we age.
So what do we know about the aging
brain? Neurons die. Actually, they die throughout the lifespan, at certain
points in our lives die at an astonishing rate. A newborn child has more
neurons in their developing brain than they will ever need – too many, in fact.
Part of early development is the loss of neurons that really have no use, called
pruning. By and large, this process is over early into our lives, and
development takes on a new job, that of creating new connections and
strengthening important connections. This is essentially learning, which
mostly occupies the first two decades of life. Our brains literally soak up
information during this time of life, for most of us working in a highly
efficient manner to store new information so that it is easily accessible. As
well, the brain becomes more efficient. Neurons that are near each other do not
necessarily need to have long connecting fibers, or axons, to communicate.
However, neurons sometimes have a long haul to get neurochemical signals to
their destinations. The longest axons in the human body literally are
stretching from head to foot (the sciatic nerve). In order to be more
efficient, such long nerves need to have a lipid-protein covering, or myelin,
to make the signal transmission go faster (in the brain the neurons do not work
wholly on electrical impulses but on electro-chemical impulses). The process of
myelination helps explain why balanced nutrition for children and teenagers is
so important for cognitive functioning. Myelination of the frontal lobes, where
emotions, behaviors, and critical thought processes are regulated, is not fully
complete until the 20s or 30s. So for parents of teenagers, it is somewhat
comforting to know that the teenage brain is not finished developing!
Starting in the late 30s to early
40s, our brains actually start to shrink, subtly at first but after the 6th
decade at a more accelerated rate. Unfortunately, neurons do not live forever.
And even if some new neuronal regeneration occurs (and we are discovering more
and more that this may be the case), remember this is only one part of the
equation, because it is the synapses, the connections among all those
neurons, that really represent what we have learned. The loss of neurons means
that synapses are becoming less robust, less efficient.
As well, aging (and the health
issues that inevitably emerge from aging) affects the efficiency of the nerve
bundles deep within the brain. This relates to blood supply to the brain.
Oxygen is the most critical need that the blood supply provides to the brain.
Neurons begin to die within one minute of oxygen deprivation, and within 3
minutes of total interruption of oxygen serious brain damage has occurred. Most
of our brains will not suffer the effects of full anoxia. However, chronic
starvation of the brain can cause cumulative damage to the neurons and their
axons. The medical term for this process is microvascular ischemia: micro (as in small) vascular (as in blood vessels) and ischemia, or restriction of blood flow to tissue. Unfortunately, in
the brain there are susceptible areas related to the type of blood vessel that
supplies that area of the brain. The blood vessels that supply the myelinated
nerve bundles in the brain are more prone to changes in blood pressure and also
to the effects of inflammation. The result is that damage can occur to these
nerves without a noticeable clinical stroke; accumulate enough of such damage
over time and this will start to affect the efficiency of the brain.
When damage to the nerves
interconnecting the neurons occurs, there will be a loss of synapses, just like
telecommunication wires being damaged by falling trees in a storm. Fewer
connections mean that the ability of the brain to access its vastly distributed
information network becomes inefficient, slower, and unreliable. In the
severest of circumstances, the neurons themselves can die from damage to their
nerves, or from the loss of connectivity. When one considers the accumulation
of such “silent” damage over time, it is not surprising that brains begin a
slow, steady decline in size somewhere around middle age.
So, how could we slow or even
possibly stop this process of cumulative damage to the brain? The answer lies
in promoting cardiovascular health. We are fairly well educated about how to
decrease risk of heart disease nowadays; most all of us have had tests to measure
qualities of heart health such as measuring blood pressure, cholesterol levels,
blood sugar, triglycerides, and such. Good heart health prevention not only
focuses on keeping track of these tests, but also taking the medical,
behavioral, and lifestyle steps to ensure heart health to the fullest extent.
In the medical realm, it is
critical to treat those diseases that affect the heart to protect the brain. So
for instance, high blood pressure should be monitored closely, medications used to help control blood
pressure (if needed), and regular medical checkups. The same thing goes for
high cholesterol, diabetes, cardiac arrhythmia, and the like. There is no
better step to take than to keep such conditions medically under control.
There are habits that are very bad for the heart and brain.
Tobacco use is a risk factor for heart disease. Chronic obstructive pulmonary
disease (COPD) can lead to serious implications for the brain, as difficulty
getting oxygen to the bloodstream due to poor lung function will have an effect
on the regular, steady supply of oxygen that the brain needs. Not getting good
sleep can be detrimental to the brain’s ability to store information. Sleep and
its cycles are intimately related to how the brain processes and stores information,
as well as repair and regenerative processes. Good sleep habits are conducive
to good sleep: schedules, routines, regularity. Also, avoiding any type of
behavior or
activity that may make it harder to get to sleep, such as consuming caffeine in
the evenings, watching television in the bedroom or actually while in the bed,
etc. Treating sleep problems medically is also important. Sleep disturbances
are often a sign of diseases that can impact the brain.
For the brain, you are what you eat. Having poor eating habits, such as eating
most calories late at night and eating irregularly, contributes to obesity,
disturbs the sleep cycle, and leads to daytime variations in glucose levels.
Fatigue can often be related to poor diet and dietary behaviors. In contrast,
there are good dietary additives and supplements that have been shown to
promote brain functioning. We know that fish oil, specifically its component
docosahexaenoic acid (DHA), is an excellent protector of heart and brain
health. Turmeric, a component of curry-based foods, is also increasingly
recognized as protective for heart functioning. Blueberries are also the latest
“super food” of the brain, as are avocados. Such food components and
ingredients likely play a role as antioxidants, which help reduce oxidative
stress and inflammation. Avocados may also help lower blood pressure.
While eating right is important,
another essential lifestyle change is the role of cardiovascular exercise.
While this is one of the lifestyle changes that may have the most impact with
the littlest cost, it is probably one of the hardest lifestyle changes to make
and maintain. It may be best to start with the small changes that are easiest
to maintain. For instance, if you are capable of it, park further away in the
parking lot. Take the stairs instead of the elevator if only going up or down a
few flights. And consider a modest and easily maintainable exercise routine.
For instance, recent research has indicated that as little as 30 minutes of
brisk walking 3 times a week can be beneficial for your health.
A last lifestyle consideration is
being more mentally active. Much like physical strength, mental strength and
endurance is a “use it or lose it” phenomenon.
Mental activity that stimulates processing speed, in particular visual
attention and processing, can actually improve speed of thinking as we age and
can result in benefits in our everyday functioning. Enter computer-assisted
cognitive training applications. While there are many such programs out there,
here are two to consider. I do not endorse these products, but they are
examples of what you might want to look for in a brain training software. One
is Lumosity: www.lumosity.com, a website
where members can use brain training activities and keep track of their
progress. Another is Brain Age: www.brainage.com, which is marketed by Nintendo for their hand-held Nintendo DS game
system. The desirable features of a brain training software would be games that
focus on concentration and reaction time, as well as keep track of your scores
over time so that you can see if your score is improving, so you have feedback
on potential improvements in your skills. Equally important to the process is periodic
“tune up” sessions, once you have achieved your goal, to maintain your
progress.
While not all cognitive aging effects can be prevented,
comprehensive lifestyle changes may help to delay the more serious cognitive
complications of aging. Consider a recent book, The Alzheimer's Prevention
Program by Dr. Gary Small and Gigi Vorgan. Dr. Small, who is an eminent
researcher in memory and memory disorders from UCLA, presents the argument
that, even if a person has family risk factors of Alzheimer's disease,
preventive measures can delay the onset of this disease. An ambitious goal, but
not impossible. Many researchers studying neurological diseases share this same
goal, and many of the drugs that will be developed in the next decades will
considerably slow onset of Alzheimer's. Until then, armed with knowledge
regarding prevention, we can put the best foot forward to improve cognitive
functioning well into older adulthood
