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.coma 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