Anatomical changes
The human brain is considered as the most complex structure in the universe. It is also a most vital organ, responsible for everything in our body from involuntary life support functions like heartbeats and breathing to the essence of personality and memory. It contains more than 100 billion cells including neurons-the specialized cells of the nervous system responsible for the transmission of electrical impulses to and from the central nervous system. Neurons can send signals to thousands of other cells at a rate of about 200 miles per hour. Just how these neurons work-a complicated system involving various chemicals (neurotransmitters) and electrical impulses-is only slowly coming to light.
Until recently, brain aging-and everything that entails, from the annoying inconveniences of age-related memory loss to more serious conditions like Alzheimer's and dementia-was equated with neuron failure. Now, scientists discovered that if you don't have a specific disease that causes loss of nerve cells, then most, if not all, of the neurons remain healthy through your life. One reason for the change: improved technology like higher resolution magnetic resonance imaging (MRI) and positron emission tomography (PET) scans. These help scientists pinpoint the parts of the brain that function or fail as individuals’ age. The technology has also generated a wealth of information about the physical changes in the aging brain, including:
- Brain weight and volume decrease.
The brain weighs around 350 g at birth and increases to around 1,375 g by the age of 20. The largest increase in brain weight takes place in the first three years of life during which time it quadruples in size. Brain weight starts to decline between the ages of 45 - 50 and decreases by around 11 per cent from its maximal weight in young adulthood.
In the older brain tissue loss is most obvious on the surface and is seen as shrinkage of the natural convolutions in brain tissue. Changes are most prominent in the forebrain and less so in the cerebellum - the area at the back of the brain mainly responsible for balance and dexterity of movement.
In the young brain the ratio of gray to white matter is 1:28 and this declines to around 1:13 in the brains of people in their sixties. Curiously, there is evidence to suggest a reversal in trend as the brain ages further with gray to white matter back to 1:55 by the age of 90.
- The grooves on the surface of the brain widen, while the swellings on the surface become smaller.
- So-called "neurofibriallary tangles," decayed portions of the branch-like dentricles that extend from the neurons, increase.
- "Senile plaques," or abnormally hard clusters of damaged or dying neurons, form.
Along with realizing these physical changes in the brain, one of the big surprises in recent years is data that suggests cognitive decline like age-related memory loss is not due to neuron loss, as previously thought. Instead, scientists now believe changes in function as we age have more to do with complex chemical interactions in the brain that occur over time.
Working Memory
A function called "working memory" occurs in the hippocampus and in the frontal cortex. Working memory is temporary storage of information and includes processes for analyzing information, decision-making and information selection. On the other hand, long term memories have been found to be stored in many different locations in the brain.
With aging, our brains change. Brain cells die off and in some people, a number of brain structures such as the hippocampus become smaller. Brain changes such as these may not have any impact on memory and the changes vary widely from person to person. Although brain cells do die off, the process does not accelerate with age, and the areas of the brain that lose cells are not necessarily the ones that relate to memory. Researchers who study the effects of aging on the brain say that even though the hippocampus shrinks, it probably compensates for its smaller size by working harder.
Though the brain’s physical changes do not necessarily relate to loss of memory, changes do occur in memory function as we age. The way the brain processes information is often slowed, affecting the rate that people can put new information into their permanent memory, especially rote, factual information. With aging, we often experience delayed recall — not being able to remember a familiar name or word — and it becomes harder to pay attention to more than one thing at a time.
In a study done by Dr. Monte Buchsbaum, Professor at the Department of Psychiatry, Mount Sinai School of Medicine, a group of young and old people who had equally good memories were tested. They were told to look at 16 words on a screen, organize the words into categories and then memorize them. The younger people used the frontal lobe, which is the part of the brain generally used for organizational tasks such as categorizing words. The older group, on the other hand, used a different part of the brain, an area used for processing visual images. According to the researchers, the results suggest that healthy aging may involve the ability to move tasks out of the frontal lobe into other areas of the brain. Though researchers do not know how this is done, the answer could help people train their brains to use different regions as they age.
Research also shows that though most older people tend to experience some memory deficiency, others maintain a high level of cognitive functioning into their later years. These "successful agers," as they are sometimes labeled, show less age-related memory loss. They generally have higher levels of education, stay involved in their work and spend more time doing activities that require complex thought.
People who have a positive mental outlook tend to show slower decline in mental functioning as they age, as well. Research is showing that a positive relationship exists between physical fitness and memory, especially for those participating in aerobic exercise.
Factors of Influence
- The genetic influence on the rate of brain aging is one of the potential factors due to the genetic evolution, favoring those who, while getting older, retained the active capacity to teach and provide emotional support to the younger people. However, until recently, the average life span was much lower, and it was rare for people to live past age 40 or 50, leading to very weak evolutionary selective pressure to make the brain work after 60. That's probably why all brains decline with aging.
- The rate of change may be hastened or slowed by lifestyle factors. For instance, maintaining a lower weight might affect brain aging. The opposite condition is diabetes-a condition with elevated blood sugar- those with diabetes typically show more signs of brain aging than non-diabetic individuals.
- Education: Those who 'use it, don't lose it' as quickly, according to studies that compare brain function in adults who attended college and those who did not. One recent study showed that cognitive challenge actually created new neurons in the adult brain, which means that the old idea that we have all the neurons in the brain when born, and then we start losing them gradually, is probably wrong.
- Exercise: Those who walk rapidly for as little as 45 minutes three times a week significantly improve age-related declines in cognitive abilities.
- Rest: A regular pattern of eight hours of sleep per night helps protect against age-related chronic illnesses including memory loss.
- Hypertension: Hypertension speeds up normal brain shrinkage and loss of mental abilities. Even those on antihypertensive medication have accelerated aging and shrinking of the brain.
- Stress: When under stress, the human body produces a hormone called cortisol. In small amounts, it can improve memory-which is what helps emotional events stay vividly in our minds. In larger amounts, however, it wears away at the neurons in the hippocampus.
- Head trauma: It has long been known that boxers get punch drunk and their brains exhibit changes that mimic Alzheimer's disease, only much earlier. A new series of studies show that former soccer players have declines in cognitive function in proportion to their use of their heads in propelling the ball.
Aging Generation
Some researchers believe that the baby-boom generation could be less at risk of cognitive decline than their parents because they have higher education levels, which may serve to increase the density of their neural synapses. People who engage in cognitive activities—reading a book, playing chess or crosswords, listening to a radio program—are less likely to lose their mental edge than those who do not. Older people can improve their memory capacity through training to the point that it equals that of untrained younger people, recent research shows.
Brain Maintenance
From the brain aging processes and factors of influence, you have probably already figured the ways on how to keep it in the best state. There are some advices from the specialists:
- Move It
“The best advice I can give to keep your brain healthy and young is aerobic exercise," says Donald Stuss, PhD, a neuropsychologist and director of the Rotman Research Institute at Baycrest Centre for Geriatric Care in Toronto.
Mark McDaniel, PhD, professor of psychology at Washington University in St. Louis, agrees, but adds, "I would suggest a combined program of aerobics and weight training. Studies show the best outcomes for those engaged in both types of exercise."
As we age, our brain cells, called neurons, lose the tree-branch-like connections between them. These connections, or synapses, are essential to thought. Quite literally, over time, our brains lose their heft. Perhaps the most striking brain research today is the strong evidence we now have that "exercise may forestall some kinds of mental decline," notes McDaniel. It may even restore memory. Myriad animal studies have shown that, among other brain benefits, aerobic exercise increases capillary development in the brain, meaning more blood supply, more nutrients and -- a big requirement for brain health -- more oxygen.
The preeminent exercise and brain-health researcher in humans is Arthur Kramer at the University of Illinois at Urbana-Champaign. In a dozen studies over the past few years, with titles such as "Aerobic Fitness Reduces Brain Tissue Loss in Aging Humans," Kramer and his colleagues have proved two critical findings: Fit people have sharper brains, and people who are out of shape, but then get into shape, sharpen up their brains. This second finding is vital. There's no question that working out makes you smarter, and it does so, Kramer notes, at all stages of life. Just as important, exercise staves off heart disease, obesity, diabetes and other maladies that increase the risk of brain problems as we age.
As we age, our brain cells, called neurons, lose the tree-branch-like connections between them. These connections, or synapses, are essential to thought. Quite literally, over time, our brains lose their heft. Perhaps the most striking brain research today is the strong evidence we now have that "exercise may forestall some kinds of mental decline," notes McDaniel. It may even restore memory. Myriad animal studies have shown that, among other brain benefits, aerobic exercise increases capillary development in the brain, meaning more blood supply, more nutrients and -- a big requirement for brain health -- more oxygen.
The preeminent exercise and brain-health researcher in humans is Arthur Kramer at the University of Illinois at Urbana-Champaign. In a dozen studies over the past few years, with titles such as "Aerobic Fitness Reduces Brain Tissue Loss in Aging Humans," Kramer and his colleagues have proved two critical findings: Fit people have sharper brains, and people who are out of shape, but then get into shape, sharpen up their brains. This second finding is vital. There's no question that working out makes you smarter, and it does so, Kramer notes, at all stages of life. Just as important, exercise staves off heart disease, obesity, diabetes and other maladies that increase the risk of brain problems as we age.
2. Feed It
Another path to a better brain is through your stomach. We've all heard about antioxidants as cancer fighters. Eating foods that contain these molecules, which neutralize harmful free radicals, may be especially good for your brain too. Free radicals have nothing to do with Berkeley politics and everything to do with breaking down the neurons in our brains. Many colorful fruits and vegetables are packed with antioxidants, as are some beans, whole grains, nuts and spices.
More important, though, is overall nutrition. In concert with a good workout routine, you should eat right to avoid the diseases that modern flesh is heir to. High blood pressure, diabetes, obesity and high cholesterol all make life tough on your brain, says Carol Greenwood, PhD, a geriatric research scientist at the University of Toronto.
If your diet is heavy, then you're probably also heavy. The same weight that burdens your legs on the stairs also burdens your brain for the witty reply or quick problem solving. The best things you can eat for your body, Greenwood notes, are also the best things you can eat for your brain. Your brain is in your body, after all. Greenwood's recommendation is to follow the dietary guidelines from the American Diabetes Association.
3. Speed It Up
Our brains naturally start slowing down at the age of 30. New studies show that people of any age can train their brains to be faster and, in effect, younger. "Your brain is a learning machine," says Michael Merzenich, PhD, a neuroscientist at the University of California, San Francisco. Given the right tools, we can train our brains to act like they did when we were younger. All that's required is dedicated practice: exercises for the mind.
Merzenich has developed a computer-based training regimen to speed up how the brain processes information (positscience.com). Since much of the data we receive comes through speech, the Brain Fitness Program works with language and hearing to improve both speed and accuracy. Over the course of your training, the program starts asking you to distinguish sounds (between "dog" and "bog," for instance) at an increasingly faster rate. It's a bit like a tennis instructor, says Merzenich, shooting balls at you faster and faster over the course of the summer to keep you challenged. Though you may have started out slow, by Labor Day you're pretty nimble.
Similarly, Nintendo was inspired by the research of a Japanese doctor to develop a handheld game called Brain Age: Train Your Brain in Minutes a Day, which has sold more than two million copies in Japan. No software out there has yet been approved by the FDA as a treatment for cognitive impairment, but an increasing number of reputable scientific studies suggest that programs like Merzenich's could help slow down typical brain aging, or even treat dementia. The biggest finding in brain research in the last ten years is that the brain at any age is highly adaptable, or "plastic," as neurologists put it. If you ask your brain to learn, it will learn. And it may speed up in the process.
To keep your brain young and supple, you can purchase software like Merzenich's, or you can do one of a million new activities that challenge and excite you: playing Ping-Pong or contract bridge, doing jigsaw puzzles, learning a new language or the tango, taking accordion lessons, building a kit airplane, mastering bonsai technique, discovering the subtleties of beer-brewing and, sure, relearning differential calculus.
- Stay Calm
While challenging your brain is very important, remaining calm is equally so. In a paper on the brain and stress, Jeansok Kim of the University of Washington asserts, in no uncertain terms, that traumatic stress is bad for your brain cells. Stress can "disturb cognitive processes such as learning and memory, and consequently limit the quality of human life," writes Kim.
One example is a part of the brain called the hippocampus, which is a primary locus of memory formation, but which can be seriously debilitated by chronic stress. Of course, physical exercise is always a great destressor, as are calmer activities like yoga and meditation. And when you line up your mental calisthenics (your Swahili and swing lessons), make sure you can stay loose and have fun.
One example is a part of the brain called the hippocampus, which is a primary locus of memory formation, but which can be seriously debilitated by chronic stress. Of course, physical exercise is always a great destressor, as are calmer activities like yoga and meditation. And when you line up your mental calisthenics (your Swahili and swing lessons), make sure you can stay loose and have fun.
- Give It a Rest
Perhaps the most extreme example of the mental power of staying calm is the creative benefit of sleep. Next time you're working on a complex problem, whether it be a calculus proof or choosing the right car for your family, it really pays to "sleep on it."
Researchers at Harvard Medical School have looked at the conditions under which people come up with creative solutions. In a study involving math problems, they found that a good night's rest doubled participants' chances of finding a creative solution to the problems the next day. The sleeping brain, they theorize, is vastly capable of synthesizing complex information.
- Laugh a Little
Humor stimulates the parts of our brain that use the "feel good" chemical messenger dopamine. That puts laughter in the category of activities you want to do over and over again, such as eating chocolate or having sex. Laughter is pleasurable, perhaps even "addictive," to the brain.
- Get Better With Age
In our youth-obsessed culture, no one's suggesting a revision to the Constitution allowing 20-year-olds to run for President. The age requirement remains at 35. You've heard about the wisdom and judgment of older people? Scientists are starting to understand how wisdom works on a neurological level.
When you are older, explains Merzenich, "you have recorded in your brain millions and millions of little social scenarios and facts" that you can call upon at any time. Furthermore, he notes, "you are a much better synthesizer and integrator of that information."
When you are older, explains Merzenich, "you have recorded in your brain millions and millions of little social scenarios and facts" that you can call upon at any time. Furthermore, he notes, "you are a much better synthesizer and integrator of that information."
Older people are better at solving problems, because they have more mental information to draw upon than younger people do. That's why those in their 50s and 60s are sage. They're the ones we turn to for the best advice, the ones we want to run our companies and our country.
As Barry Gordon, a neurologist at The Johns Hopkins School of Medicine and author of Intelligent Memory: Improve the Memory That Makes You Smarter, puts it, "It's nice to know some things get better with age."
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