Save Your Brain: The 5 Things You Must Do to Keep Your Mind Young and Sharp_5

44 Save Your Brain I became interested in this work, and I wanted to know how researchers defined an enriched environment. My review of this work suggests three factors were critical to the enriched environment: socialization (animals had to have other animals of their own kind in the environment); physical activity (ani-mals had a running wheel to exercise on); and mental stimula-tion (there were toys in the environment animals could play and interact with). Animals raised in unenriched environments were raised in isolation, had no running wheel, and had no toys to play with. While this research offered highly significant and important findings regarding the effects of the environment on brain structure in the animal, the critical issue of whether the same findings could be established for humans remained unknown. When thinking about a proactive brain health lifestyle, I believe the three critical factors of the enriched environment found in the animal studies are equally important to humans. Plenty of research supports the role of socialization, physical activity, and mental stimulation in reducing the risk of demen-tia in humans. However, the human organism is more com-plex than rodents and is stimulated by environmental input that is also more complex in nature. As you will learn in later chapters, my brain health lifestyle recognizes the complexity of the human brain by including two new factors, nutrition and spirituality, in addition to the three factors established from the animal literature. How Your Brain Works 45 How Environment Affects the Human Brain It was not until the late nineties that a landmark study dis-covered that the human brain has the ability to generate new brain cells. This study was a threshold moment for our species, as it confronted traditional thought that the human brain was a rigid system with no ability to regenerate. We had always believed the brain was born with all of its brain cells, that the human brain lost brain cells on a daily basis, and that our brains did not replace the lost cells with new ones. The study also indicated that the new brain cells were generated in the human hippocampus, analogous in animals to an area neurogenesis was found in the animal brain. Today, research is ongoing to deter-mine if neurogenesis occurs in other regions of the human brain or if it is specific to the hippocampus. New brain cell development is one outcome of a brain with plasticity. Remember, plasticity refers to a brain that is dynamic, constantly reorganizing, and malleable. The human brain, therefore, is now thought to possess the same type of neural plasticity as the rodent brain. Interestingly, the animal studies were conducted on rodents across their life span with an equivalent human age of seventy or eighty. A human brain that generates new brain cells mandates a curiosity of how this wonderful adaptive ability occurs. We can return to the animal studies to derive some answers to this question. The enriched environment led to new brain cell development in the hip-pocampus of the animal. The three critical factors important to the enriched environment in this study included socialization, 46 Save Your Brain physical activity, and mental stimulation. Therefore, it makes sense to ask if the human brain is similarly affected by environ-ment and if the enriched environment promotes positive brain changes in the human. As you will read in the next chapter, there is good reason to believe that the human brain benefits from a novel and complex environment. Similar to the enriched environment discussed in the animal research above, novelty and complexity infers stimu-lation that demands more of the human cerebral cortex and increases the potential for development of brain reserve. Stimuli that are novel and complex require the cortex to be engaged, as the brain has either not been exposed to the information before or it has not mastered the information. In contrast, pas-sive, rote talents or overlearned information rely more on the subcortex and are not thought to be as brain health promoting. It is also important to know that the first potential enriched environment is the womb and that the type of environment you expose your brain to will have consequences your entire life. The miracle of brain plasticity does not end at a particular age. Indeed, the human brain probably does not know its chrono-logical age and will demand and benefit from enriched environ-ments at every age. The major point of this section is that you are strongly encouraged and empowered to expose your brain to the novel and complex every day regardless of your age! Enhancing Brain Reserve Brain reserve is a well-known concept that refers to a buildup of brain cell connections that serves to assist the brain in the How Your Brain Works 47 battle against neurodegenerative diseases. To better understand brain reserve, consider the following simple analogy that I use in my lectures on the human brain. Imagine flying in an air-plane nearly a thousand feet above the ground. As you peer out your window down at the ground, you will see two very distinct scenes. The first scene is a jungle where there are so many trees you cannot see the ground. The second scene is an island with one palm tree blowing slowly in the wind. You want your brain to be like the jungle, the lush foliage symbolizing a tremendous number of synaptic connections. This is referred to as synaptic density and is a direct measure of brain reserve. You do not want your brain to look like the island with one palm tree. The reason is also simple. Think of Alzheimer’s or other types of dementia or brain disease as a weed-whacker: the disease will invade the brain and begin to cut down the neurons and synaptic connections. This occurs just like a weed-whacker cutting through the weeds around your house. If your brain looks like a jungle, filled with synaptic connections, it will take Alzheimer’s or another brain disease a long time to show its ugly clinical face. However, if your brain looks like the island with one palm tree, the clinical signs of Alzheimer’s will mani-fest quickly because there is no reserve to fight it off. Indeed, some research has shown that even though brains are diagnosed with Alzheimer’s at autopsy due to the presence of neuropathological markers such as tangles and plaques, a sig-nificant number of these persons never demonstrated the clini-cal aspects of the disease in life. This is explained one way using the brain reserve concept. Perhaps people who never manifested Alzheimer’s in life, even though they had the neuropathologic 48 Save Your Brain characteristics in their brain at autopsy, had built up brain reserve to fight off or delay the onset of the disease. The power of brain reserve to stave off the effects of Alzheimer’s is further supported by findings that relate higher education and occupational levels to lower risk of Alzheimer’s. For those with high education or occupation levels who do manifest Alzheimer’s, their disease begins to emerge later on than for those without this kind of background, and once the disease manifests, they die soon after. The theoretical reason for this is that when the disease presents clinically, it is already advanced into the final stage because the person’s brain reserve had been fighting it off. Educational settings and workplace settings are good exam-ples of environments that can be enriched. You expose your brain to these environments frequently across over the course of your life. Each of these two environments provides the oppor-tunity for you to engage in a novel and complex setting that promotes the development of brain reserve. To the extent that these environments or other settings become rote and passive, brain reserve will not be as developed, and the overall health benefit for your brain is not enhanced. It is your personal challenge to expose your brain to novel and complex experiences and enriched environments on a daily basis. Studies suggest the earlier in life you begin to expose yourself to enriched environments, the greater the health ben-efit to your brain—even well into your late life. This finding is supported by research that demonstrates that having a higher IQ in childhood and young adulthood reveals a reduced risk of Alzheimer’s and other brain health issues later in life. Lan-guage development in young adulthood also reveals a reduced ... - tailieumienphi.vn