The human brain, which weighs about three pounds and is composed of approximately 100 billion nerve cells (neurons), is the most complex organ in the body. The brain not only controls our heart rate, breathing, blood pressure and body temperature, but also allows us to walk and talk as well as see, hear, smell, think, remember and create.
Scientists have long sought to understand the inner workings of the human brain—and, more specifically, how we process both learning and memory.
Among the important discoveries in this field are those of Eric R. Kandel, MD, a winner of the Nobel Prize for his lifelong research into the biological basis of learning and memory.
Originally trained as a psychiatrist at New York University School of Medicine and Harvard Medical School, Dr. Kandel has written many scientific papers on brain function and is coauthor of Principles of Neural Science, generally considered to be the standard textbook in the field.
We interviewed Dr. Kandel to learn more about his research and its implications for a healthier brain and a happier life…
- What is the essence of the research for which you were awarded the Nobel Prize? I was recognized for mywork on the molecular biology of learning and memory. Throughout my career, I have been extremely interested in the biology of learning.
- What changes in the brain as we learn? And, once something is learned, how is that information retained in the brain? Our most basic finding was that the physical structure of the brain actually changes through the process of learning—whether it's learning to use a computer or speak a foreign language.
- What does that finding mean in terms of memory in humans? Over the past 50 years, my colleagues and I have delineated the biological—the molecular and cellular—basis of both short- and long-term memory in a simple experimental system, the marine snail aplysia.
Short-term memory (a memory that lasts for a few minutes) is controlled by a functional change in the brain—a change in the strength of communication from one nerve cell to another. This often is mediated by an intracellular "signaling" molecule, such as cyclic adenosine monophosphate (cAMP), that helps relay information from the synapse of a nerve cell to its nucleus.
Long-term memory (a stored memory that lasts days or even a lifetime) involves an anatomical change, with the growth and strengthening of synapses (connections between nerve cells). In this case, cAMP enters the nucleus of the nerve cell and stimulates memory-enhancer genes, which in turn activate the growth of these new connections. Short-term memory commonly is converted to long-term memory by repetition.
- What are some of the implications of this research? Based on these findings, several colleagues and I started the company Memory Pharmaceuticals in 1996 to develop drugs to treat memory loss. The company has created several families of compounds. One is for benign senescent forgetfulness—non-Alzheimer's age-related memory loss.
Age-related memory loss can begin in a person's 40s and worsen with time, and it affects the ability to convert short-term memory into long-term memory. For example, this could be remembering the next morning the name of a person you met at a dinner party the evening before. Another family of compounds is intended to reverse the early phases of Alzheimer's disease.
Currently, the compounds are being tested in the laboratory—some of them improve a rat's memory of a new task for months. Another few years of research and testing might lead to medications for humans that were scarcely imaginable just a few years ago.
- What do these discoveries about shortand long-term memory tell us about human capability? Obviously, there is a genetic predisposition for many capabilities, but superimposed upon that is a huge capability to modify predispositions through learning.
This capability allows you to change the very architecture of your brain. Since learning leads to anatomical changes, every single brain is different from every other brain—by virtue of learning.
- What's the best way to keep one’s brain healthy?
There are factors that are important for long-term mental functioning, such as not being overweight and not being physically inactive, both of which reduce blood flow to the brain.
It is also important to see life as an adventure—to see oneself not in a static state, but in a process of continual growth and a state of expanding knowledge. Otherwise, one can become intellectually lazy.
But most of all, you should stay intellectually active, through learning new things and facing new mental challenges, whether it is solving a crossword p:uzzle, or learning a new language.
Interacting with young people also is intellectually invigorating—they challenge your established thinking and help you think in new, fresh ways.
- Dr. Kandel, you are one of the world's most successful scientists. What lessons have you learned that could be applied to any individual's professional life?
Three lessons have been most important to me throughout my career.
First, learn to trust your own judgment. When you reach a certain intellectual maturity—when you have developed a way of thinking that has not proven at least moderately effective—trust your instincts for new ideas.
I have often gone in directions that I felt were interesting but initially seemed to be quite "fvzzy"—yet they have turned out to be quite fruitful in the long run.
For example, I started my work on memory by studying marine snails, which seemed a wild idea to some scientists. However, I thought that the technical advantages of studying a particular species of snail were extraordinary in part, because some of this snail's brain cells are the largest in the animal kingdom. That proved to be a sound judgment.
Second, don't be afraid to change directions, even if it involves learning a new discipline. At almost every phase of your life, you're fully capable of developing new intellectual skills. Don't be frightened of something because you're inexperienced. With time and effort, there's no reason why you can't master a new discipline.
Lastly, be willing to be bold. 'Within reason, take chances intellectually. If you tackle important problems in original ways—even if you fail—that's preferable to doing something everyone else can do as well as you can.
- What will science reveal about the mind in the 21st century?
In the next 50 years, we will understand, through improvement in brain imaging and improvements in the use of animal models, many details of mental function. There will be a new "science of mind" that will revolutionize how we think about ourselves and our interactions with others.
We will begin to comprehend in biological terms the brain-based biology of behavior, social cognition, decision-making in business, our appreciation of the arts and much more.
We also will develop effective approaches, such as new medications, to treat brain diseases, including age-related memory loss, Alzheimer's disease and mental illnesses such as depression and schizophrenia.
The biology of mind—the science of mind—will enlighten all aspects of mental life, for the betterment of individuals and all of humankind.
Surprising Ways to Fight Fatigue! Boost Mood! Prevent Stroke! More
Though many of the brain's inner workings remain a mystery, scientists make new discoveries about this powerful organ almost weekly. Recent brain research has revealed ways to significantly improve memory and mental ability along with practical ways to prevent stroke and other brain diseases, including Alzheimer's.
Boost Performance With Stress
Scientists used to view stress as a detriment to mental performance. They advised people who were trying to improve learning and memory skills to minimize stress—with regular meditation, yoga, etc.
New finding: People learn more efficiently when they maintain an optimal level of stress. A principle called the Yerkes-Dodson Law has shown that a certain amount of stress (arousal) motivates people to try harder.
Balance is the key. People who experience very little stress—when taking a test or writing a paper, for example—tend to make errors of omission, such as forgetting to complete all the answers. People who experience too much stress make errors of commission, such as hitting the wrong computer keys.
What to do: If you find you're making more errors than usual in completing a task, you're probably experiencing too much stress. If you're bored, your stress levels are too low. For optimal mental performance, it is best to be in between these two extremes.
How to achieve stress balance: Too much stress is typically caused by one of two factors—having too few personal resources in a demanding situation or feeling that you have no options.
In the first case, increase your resources (practice, learn new skills, find helpers) or decrease the demands made on you (change to a less demanding task, simplify the task in some way).
In the second case, talk with your associates or with a counselor or doctor to identify ways to gain more control over the situation.
Too little stress is caused by having too many resources in a situation that is not very demanding—you are overqualified for the task at hand. Address this by handicapping or otherwise limiting yourself.
Example: When my daughter was younger and I played tennis with her, I would hit to her singles court, while she hit to my doubles lanes—so the tennis became more interesting for me. Or you can increase the level of difficulty or complexity of what you are doing. For example, if you are bored writing something, try doing it without using the verb "to be."
Reduce Stroke With Chocolate
People who consume moderate amounts of chocolate have better brain circulation and can reduce their risk of stroke. Cocoa beans—the main ingredient in chocolate—contain natural antioxidants called cocoa flavonoids. The flavonoids in chocolate are more powerful than vitamin C at limiting fatty deposits (plaque) in arteries in the brain and heart. Buildups of plaque can impair mental performance and are the main cause of strokes.
Chemical compounds in chocolate also increase the levels of nitric oxide, a critical compound in the blood that relaxes the inner walls of blood vessels and promotes better blood flow and lower blood pressure. A study of 470 healthy men in the Netherlands found that those who ate the most cocoa beans—in the form of chocolate bars, pudding, hot cocoa, etc.—had lower blood pressure and half the risk of dying during the study period than those who ate the least.
What to do: Have one to two cups of cocoa or two small squares of a bar of chocolate daily. The darker the chocolate, the better. According to the ORAC scale—a measure of the antioxidant levels in foods—dark chocolate has double the amount of antioxidants of milk chocolate.
Fight Afternoon Fatigue
Nearly everyone gets sleepy after lunch. You can prevent this afternoon slump by eating protein first during lunch, then carbohydrates. The protein triggers an energy-promoting amino acid in the brain.
Foods that are high in complex carbohydrates, such as whole-grain bread, fruits and vegetables, are good for you, but they contain an abundance of the amino acid L-tryptophan, which promotes relaxation and sleepiness. High-protein foods, such as meats and fish, contain L-tyrosine, which makes you more alert and less likely to feel tired.
Your energy level after you eat will depend on which of these amino acids reaches your brain first.
What to do: Start your meal with a bite or two of protein. This allows the L-tyrosine to reach the brain before the L-tryptophan. But don't just eat protein—carbohydrates are your body's main source of fuel.
Get Happy With Omega-3's
In countries such as Norway and Japan, where people eat the most fish—the best source of omega-3) fatty acids—the incidence of depression and suicide is much lower than in countries where people eat less. Omega-3s can help prevent and treat a variety of disorders, including bipolar disorder and attention deficit hyperactivity disorder (ADHD).
Unfortunately, Americans get excess amounts of another fatty acid group, the omega-6s, found mainly in meats, cooking oils and soybeans. In the last century the ratio of omega-6s to omega- 3s has soared, increasing the risk of mood disorders, including depression.
What to do: Eat three to four fish servings weekly to get more omega-3s. (Avoid fish high in mercury, such as shark, swordfish, tilefish and king mackerel, as well as large tuna, such as albacore, yellowfin, bigeye and bluefin) Or you can eat nuts if you prefer. Ten to 15 walnut halves or 15 to 20 pecan halves provide the recommended daily amount of omega-3s.
Rest - But Don't Nap!
The inventor Thomas Edison was famous for getting by on only two to four hours of sleep a night. When he was working on a particularly difficult problem, he would rest for five to 10 minutes. In the brief period between wakefulness and sleep, he often would experience an “A-ha!” moment and find the solution to his problem.
Scientists have found that when the brain goes into an "alpha state”—characterized by brain waves that are slower than the beta waves of wakefulness-people often develop insights, along with more focus and energy.
What to do: Shut your eyes and let your mind relax for five to 10 minutes. Resting in this fashion is not sleeping. People who slip into true sleep are groggy and less alert when they wake up.
Prevent Alzheimer's With "Idea Density"
The important Nun Study funded by the National Institute of Aging—a long-term study of 678 members of the School Sisters of Notre Dame, ages 75 to 106—revealed that cloistered nuns with brain changes characteristic of Alzheimer's disease didn't necessarily have cognitive impairments. Why do some people with these brain changes (apparent during autopsies) develop Alzheimer's, while others do not?
When researchers analyzed short biographies that the nuns had written upon taking their vows decades earlier, they found that those with a high "idea density" (many thoughts woven into a small number of words)—a marker of educational level and vocabulary—were less likely to develop Alzheimer's symptoms later in life, even when their brains showed signs of the disease.
The brain continues to form neurons and connections between neurons throughout life. People who are mentally active form the most connections and develop brain reserves that can slow the onset of Alzheimer's symptoms.
What to do: Stay mentally engaged. Take classes at a university or community college. Read challenging books and periodicals. Keep a diary or do crossword puzzles. Learn a new language.
Take Learning Breaks
You'll learn most efficiently when you focus on one thing at a time, then take a break before moving on to new material.
Example: Someone learning a new golf swing needs about six hours for the new neural pathways to become established. If he/she tries to learn a second swing within that six-hour window, the new information will crowd out the previous learning.
What to do: If you're in school, studying for a professional exam or just trying to learn a new skill, save the beginning of each day for major new learning. Use the rest of the day for practice and repetition.
Suppose you're learning a new language, such as Spanish. You might spend the morning memorizing verbs with "-ir" endings. Practice this during the day or practice material learned on previous days, but don't introduce verbs with "-er'' endings until the next day.