Frederick had a massive stroke when he was in his mother’s womb and his entire left side of the body was affected. He could not crawl nor walk and could not talk until he was three years old. An MRI scan revealed that 25% of his brain was dead. He made some progress using conventional methods and at the age of four he was able to walk with a leg brace and talk with difficulty. But his progress plateaued. At that time his mother took him to Edward Taub’s clinic for treating him using Constrained-Induced (CI) movement therapy. CI forces patients to use the affected side by restricting the use of unaffected side. In Frederick’s case he was forced to use only his left side.
Excerpt from The Brain That Changes Itself
A mere nineteen days into the therapy, “lefty” developed a pincer grasp. “Now,” says his mother, “he can do anything with that left hand, but it is weaker than the right. He can open a Ziploc bag, and he can hold a baseball bat. He continues to improve every day. His motor skills are dramatically improved. That improvement started during the project with Taub and has continued ever since. I can’t think of anything I do for him other than being a typical parent, as far as assisting him goes.” Because Frederick became more independent, his mother was able to go back to work.
Frederick is now eight, and he doesn’t think of himself as disabled. He can run. He plays a number of sports, including volleyball, but he has always loved baseball best. So that he can keep his glove on, his mother sewed Velcro inside it, which fastens to the Velcro on a small brace he wears on his arm.
Frederick’s progress has been phenomenal. He tried out for the regular baseball team— not one for handicapped children— and made the cut. “He played so well on the team,” says his mother, “that he was chosen by the coaches for the all-star team. I cried for two hours when they told me that.” Frederick is right-handed and holds the bat normally. Occasionally he loses his left-hand grip, but his right hand is now so strong that he can swing one-handed.
Frederick’s brain was able to rewire itself and made the left side operational. This story clearly shows that human brain is malleable. But a curious mind should ask if our brain is malleable from the cradle to the grave? In the book The Brain That Changes Itself author Norman Doidge tells that our brain is plastic and it can rewire itself at any age if it’s provided with right inputs. In this post I will be summarizing my learnings from this book.
Let us get the basics right
Nervous system is divided into two parts; central nervous system and peripheral nervous system. Brain and spinal cord forms the central nervous system. It is our command-and-control center. The peripheral nervous system, which brings messages from the sense receptors to the spinal cord and brain and carries messages from the brain and spinal cord to the muscles and glands.
Brain and spinal cord is made up of many cells and one of them is a nerve cell or neuron. Neurons are cells that send and receive electro-chemical signals to and from the brain. There are about 100 billion neurons in our brain. Each neuron has three parts; dendrites, cell, and axons.
The dendrites are treelike branches that receive input from other neurons. These dendrites lead into the cell body, which sustains the life of the cell and contains its DNA. Finally the axon is a living cable of varying lengths (from microscopic lengths in the brain, to some that can run down to the legs and reach up to six feet long). Axons are often compared to wires because they carry electrical impulses at very high speeds (from 2 to 200 miles per hour ) toward the dendrites of neighboring neurons.
A neuron can receive two kinds of signals: those that excite it and those that inhibit it. If a neuron receives enough excitatory signals from other neurons, it will fire off its own signal. When it receives enough inhibitory signals, it becomes less likely to fire. Axons don’t quite touch the neighboring dendrites. They are separated by a microscopic space called a synapse. Once an electrical signal gets to the end of the axon, it triggers the release of a chemical messenger, called a neurotransmitter, into the synapse. The chemical messenger floats over to the dendrite of the adjacent neuron, exciting or inhibiting it. When we say that neurons “rewire” themselves, we mean that alterations occur at the synapse, strengthening and increasing, or weakening and decreasing, the number of connections between the neurons.
Our brain has specific processing areas called as brain maps. When we use our right hand the information gets processed in one location and when we smile the information gets processed in another location in the brain. By having specific processing areas, our brain can handle things efficiently. This is similar to how Adam Smith’s pin factory worked. Also the brain map is organized topographically; the map is ordered as the body itself is ordered. Our middle finger sits between our index finger and ring finger. The map for the middle finger sits between the map for our index finger and ring finger. Topographical organization is efficient, because it means that parts of the brain that often work together are close together in the brain map, so signals don’t have to travel far in the brain itself. By the process of evolution by natural selection our brain has worked out an efficient design. But a curious mind should ask how does this topographic order emerge in the brain map?
A topographic order emerges because many of our everyday activities involve repeating sequences in a fixed order. When we pick up an object the size of an apple or baseball, we usually grip it first with our thumb and index finger, then wrap the rest of our fingers around it one by one. Since the thumb and index finger often touch at almost the same time, sending their signals to the brain almost simultaneously, the thumb map and the index finger map tend to form close together in the brain. (Neurons that fire together wire together.) As we continue to wrap our hand around the object, our middle finger will touch it next, so its brain map will tend to be beside the index finger and farther away from the thumb. As this common grasping sequence—thumb first, index finger second, middle finger third— is repeated thousands of times, it leads to a brain map where the thumb map is next to the index finger map, which is next to the middle finger map, and so on. Signals that tend to arrive at separate times, like thumbs and pinkies, have more distant brain maps, because neurons that fire apart wire apart.
Since the brain maps had one location for one function, the medical community incorrectly generalized that if a part was damaged, the brain could not reorganize itself or recover that lost function. There were several evidences to disprove the claim but majority of the doctors ignored them. In fact they rejected papers that had the word plasticity in it. They were operating under psychological denial. Those who know about efficient market theory in finance should not be surprised by this behavior. It took several decades of work from people like Michael Merzenich, VS Ramachandran, and Edward Taub to prove that the brain is plastic and it can be rewired at any age.
Use it or lose it
A monkey’s hand like a human’s has three main nerves – radial, median, and ulnar. The median nerve conveys sensation from the middle of the hand. The other two conveys information from either side of the hand. In one experiment, Merzenich with the help of his friend Jon Kaas cut the median nerve in monkey’s hand. Two months later he remapped the monkey’s brain and found out that brain map that serves the median nerve showed no activity when he touched the middle part of the hand. But he was shocked by something else.
When he stroked the outsides of the monkey’s hand— the areas that send their signals through the radial and ulnar nerves—the median nerve map lit up! The brain maps for the radial and ulnar nerves had almost doubled in size and invaded what used to be the median nerve map. And these new maps were topographical. This time he and Kaas, writing up the findings, called the changes “spectacular” and used the word “plasticity” to explain the change, though they put it in quotes.
The experiment demonstrated that if the median nerve was cut, other nerves, still brimming with electrical input, would take over the unused map space to process their input. When it came to allocating brain-processing power, brain maps were governed by competition for precious resources and the principle of use it or lose it.
The competitive nature of plasticity affects us all. There is an endless war of nerves going on inside each of our brains. If we stop exercising our mental skills, we do not just forget them: the brain map space for those skills is turned over to the skills we practice instead. If you ever ask yourself, “How often must I practice French, or guitar, or math to keep on top of it?” you are asking a question about competitive plasticity. You are asking how frequently you must practice one activity to make sure its brain map space is not lost to another.
If we do not use a skill we will lose it. Charlie Munger in one of his talks spoke about this.
Cultivate good habits early
Dictionary meaning of habit is a settled or regular tendency or practice, especially one that is hard to give up. Habits profoundly change our neural structures and take up space in the brain map. This is true for both good and bad habits. Once a habit occupies the brain map it is very hard to get rid of it. Imagine if it is occupied by a bad habit like drug addiction. Life will be a misery. It is very important to form good habits at a young age.
Competitive plasticity also explains why our bad habits are so difficult to break or “unlearn.” Most of us think of the brain as a container and learning as putting something in it . When we try to break a bad habit, we think the solution is to put something new into the container. But when we learn a bad habit, it takes over a brain map, and each time we repeat it, it claims more control of that map and prevents the use of that space for “good” habits . That is why “unlearning” is often a lot harder than learning, and why early childhood education is so important—it’s best to get it right early, before the “bad habit” gets a competitive advantage.
Anatoly Sharansky, the Soviet human rights activist, used mental chess to survive in prison. In 1977 he was falsely accused of spying for the United States. He spent nine years in a Siberian prison and of which he spent 400 days in solitary confinement. The punishment cell was dark, measuring only five-by-six foot, and it was freezing cold. Under these extreme conditions, human brain loses its brain maps and needs some external stimulation keep it alive. What did Sharansky do?
During this extended period of sensory deprivation, Sharansky played mental chess for months on end, which probably helped him keep his brain from degrading. He played both white and black, holding the game in his head , from opposite perspectives— an extraordinary challenge to the brain . Sharansky once told me, half joking, that he kept at chess thinking he might as well use the opportunity to become the world champion. After he was released, with the help of Western pressure, he went to Israel and became a cabinet minister. When the world champion Garry Kasparov played against the prime minister and leaders of the cabinet, he beat all of them except Sharansky.
It is very important to keep our thoughts clean. Bad thoughts like envy, jealousy, anger, and self-pity will cause structural changes to our brain maps in a negative way. Why waste our brain maps on such negative thoughts when there is zero upside and infinite downside? In one experiment, Drs. Guang Yue and Kelly Cole showed that imagining one is using one’s muscles actually strengthens them.
The study looked at two groups, one that did physical exercise and one that imagined doing exercise. Both groups exercised a finger muscle, Monday through Friday, for four weeks. The physical group did trials of fifteen maximal contractions, with a twenty-second rest between each. The mental group merely imagined doing fifteen maximal contractions, with a twenty-second rest between each, while also imagining a voice shouting at them, “Harder! Harder! Harder!”
At the end of the study the subjects who had done physical exercise increased their muscular strength by 30 percent, as one might expect. Those who only imagined doing the exercise, for the same period, increased their muscle strength by 22 percent. The explanation lies in the motor neurons of the brain that “program” movements. During these imaginary contractions, the neurons responsible for stringing together sequences of instructions for movements are activated and strengthened, resulting in increased strength when the muscles are contracted.
Learnings helps your brain grow
Value learning over money. Learning increases the number of branches in our neurons and it leads to more knowledge. In today’s knowledge economy money follows those who have knowledge. Even if money does not follow you should not worry as the process of acquiring knowledge is fun. After all the goal in life is to have fun. Is it not?
Animals raised in enriched environments—surrounded by other animals, objects to explore, toys to roll, ladders to climb, and running wheels— learn better than genetically identical animals that have been reared in impoverished environments. Acetylcholine, a brain chemical essential for learning, is higher in rats trained on difficult spatial problems than in rats trained on simpler problems. Mental training or life in enriched environments increases brain weight by 5 percent in the cerebral cortex of animals and up to 9 percent in areas that the training directly stimulates. Trained or stimulated neurons develop 25 percent more branches and increase their size, the number of connections per neuron , and their blood supply. These changes can occur late in life,though they do not develop as rapidly in older animals as in younger ones. Similar effects of training and enrichment on brain anatomy have been seen in all types of animals tested to date.
For people, postmortem examinations have shown that education increases the number of branches among neurons. An increased number of branches drives the neurons farther apart, leading to an increase in the volume and thickness of the brain. The idea that the brain is like a muscle that grows with exercise is not just a metaphor.