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CHAPTER 1
Your Aging Brain
"The brain is not, like the liver, heart, and other internal organs, capable from the moment of birth of all the functions which it ever discharges; for while in common with them, it has certain duties for the exercise of which it is especially intended, its high character in man, as the organ of conscious life, the supreme instrument of his relations with the rest of nature, is developed only by a long and patient training."
— R. V. Pierce (The People's Common Sense Medical Advisor in Plain English, 1917)
From the moment of conception, our brains are developing, growing, and changing, and scientists and researchers are constantly discovering new information about how our brains develop throughout our lives.
For instance, it had long been thought that the human brain created crucial neural pathways in the early years of life and then, over the course of a lifetime, worked to reinforce and strengthen the most important of these connections, while pruning away those that were underutilized. In other words, the brain was formed and influenced in early years, remained largely unchanged in middle years, and declined in old age.
Throughout the last few decades, as scientific research techniques have become more sophisticated, our ability to learn about the complexities of the brain has accelerated. Now scientists are discovering that the growth of the brain is far more complicated and ongoing than previously supposed. Studies have shown that crucial development in the prefrontal cortex occurs after the teen years, and other researchers have discovered that brain cells can continue to develop well into old age.
It is amazing to consider how our brains — these three-pound organs that constantly grow and change throughout our lives — are charged with the oversight of our entire being. This mass of tissue and nerves drives our intelligence, interprets input from our senses, initiates the movement of our limbs, and regulates the social aspects of our behavior.
In this chapter, I will talk about the structure of the brain and how choices you make about your environment, lifestyle, nutrition, and other factors can impact the health of your brain as you age.
Understanding the Brain
To get the most out of the Reboot Your Brain program, you need to have some knowledge of the most basic structures and workings of the brain and to understand how external factors influence both the growth and decline of this amazing organ.
The Architecture of the Brain
Our brains sit under our scalps, within the bony safety of our skulls, floating in cerebrospinal fluid and covered by the meninges. The meninges consists of three layers: the dura mater, a thick membrane that can restrict the movement of the brain within the skull, preventing movements that may burst the blood vessels of the brain; the middle layer, or arachnoid; and the layer closest to the brain, the pia mater. Our brains are nourished by our circulatory systems, which convert the nutrients in our blood into fuel for the ongoing computations of the brain's billions of nerve cells. The brain is covered with a thin layer of tissue called the cerebral cortex. This coating is also called gray matter because the nerves in this area lack the insulation that makes other parts of the brain appear white. Most information processing takes place in the cortex.
The Forebrain
When you look at a picture of the brain, it is likely that the first part you notice is the cerebrum. This intricate, wrinkled area, along with its covering (the cortex) is the source of higher-level functions. It holds memories and allows you to plan, imagine, and create. This is the part of your brain you use in problem solving, abstract thinking, and making judgments. The cerebrum is split down the center by a deep fissure, creating two halves, each with very different functions. At the base of the split is a thick construct of nerve fibers called the corpus callosum, which keeps communication flowing between the halves of the brain. Signals from the brain cross over on their way to the body.
The right cerebral hemisphere controls primarily the left side of the body, and the left hemisphere controls primarily the right side of the body. In most people, the left hemisphere is dominant in controlling responses, as well as language production and understanding and cognitive functions. The right side of your brain controls temporal and spatial relations, pattern recognition, recognition of complex auditory tones, and communication of emotion.
Each of the cerebral hemispheres in the forebrain can be further divided into sections called lobes, which govern specific functions.
• The frontal lobes lie directly behind your forehead and control your ability to plan, reason, and imagine. They are also important in memory construction. The rear part of the frontal lobes has a motor area that controls voluntary movement. On the left frontal lobe, a section called Broca's area works to transform thoughts into words.
• The parietal lobes govern sensory combinations and comprehension of stimuli, such as touch, taste, temperature, and movement. The parietal lobes also function in reading and arithmetic.
• The temporal lobes are associated with music, memory, and sensation. These lobes also process emotion, including strong emotions such as fear. They are important in forming and retrieving memories.
• The occipital lobes process images from the eyes and link that information with images stored in memory.
The Midbrain
This area of the brain controls some reflex actions and is responsible for some voluntary movements.
The Hindbrain
The lowermost area of the brain is composed of the upper part of the spinal cord, the brain stem, and a wrinkled ball of tissue called the cerebellum. The hindbrain governs cardiac, respiratory, and vasomotor centers.
The Limbic System
Deep within the brain, hidden from view, lie the structures that make up the limbic system, the area of the brain that is responsible for our emotional states. These gatekeepers of the brain include:
• The hypothalamus, a structure the size of a pearl, which works as a regulator, returning your body's systems to a "set point." The hypothalamus controls hunger, thirst, response to pain, and sexual satisfaction, as well as our emotions, such as anger, unhappiness, joy, and excitement.
• The thalamus acts as a clearinghouse for information flow between the cerebrum and the spinal cord. Clusters of nerve cells called basalganglia surround the thalamus and are responsible for integrating movements.
• The hippocampus works as a memory indexer and is vital in the construction and reconstruction of memory.
• The amygdala regulates our stress responses to fear and anxiety.
Communication in the Brain
All the structures in the brain communicate with each other and the rest of the body by sending signals through cells called neurons. Information passes from one neuron to another at a junction called a synapse. Chemicals known as neurotransmitters are released by one neuron, cross the synapse, and attach to a receptor in a neighboring cell. There are at least one hundred known neurotransmitters, all with individual chemical reactions that occur constantly at the millions of synaptic junctions in our brains.
Key neurotransmitters, which help the brain function quickly and smoothly, include acetylcholine, serotonin, dopamine, glutamate, and gamma amino butyric acid (GABA). Maintaining the delicate balance of these neurotransmitters within the brain is crucial to brain health.
Aging and the Brain
Our brains begin to form just three weeks after conception and continue to develop, expand, and adapt throughout our lifetimes. Babies are born with more than one hundred billion neurons, roughly the same number they will always have. Throughout the next three years, trillions of synaptic connections form between these neurons. During this period of time, frequently stimulated synapses strengthen and proliferate, and rarely used synapses are discarded. Scientists use the term "plasticity" to define this period of adaptive growth.
Until rather recently, the prevailing theory had been that, from adolescence through adulthood and old age, the brain continues to simply discard neuronal connections. Doctors told elderly patients experiencing age-related conditions such as memory loss and mental fatigue that there was nothing they could do but accept the inevitable. "Old" neurons had died, and there were no new cells to replace them. A decline in mental sharpness was an inevitable by-product of aging.
But research has shown that our brain — this amazing organ that grows and learns through interacting with the world through both perception and action — can continually adapt and rewire itself. A Princeton research team discovered there is a natural regenerative mechanism in the mature brain that creates neurons that migrate to the cerebral cortex, where they "plug in" and become a new part of the brain's central circuitry.
Think about the brain of an infant, which is constantly amassing new information and stimulation and enrichment for the neurons forming synaptic connections. Now consider your own perceptions about challenging your brain when you are middle-aged or during your elder years. Stimulation, mental activity, and challenge all are essential in brain growth and vitality. This new research brings new urgency to a key maxim for vigorous mental health at any age: "Use it or lose it!"
But clearly the issue of what weakens our brain function is not simply the act of aging. Despite what we have been told for decades, we need not accept the idea that our bodies, or our brains, simply and inevitably "wear out" as we grow older. Staying vital both mentally and physically as we age requires paying close attention to the mind — body connection and the effects outside factors such as environment, nutrition and diet, and stress and emotion bring to bear on our welfare.
Negative Factors and Brain Weakness
What does happen, as we grow older, is that we begin to experience the cumulative effects of negative lifestyle habits and outside influences. Mental health conditions that have been labeled "age-related" are more often the result of our neglect of our bodies and our brains. If we understand the negative factors and how they impact our mental vitality, we can make the changes necessary to ensure vigorous mental health throughout our lifetimes.
In the rest of this chapter, I discuss the key factors in your environment and lifestyle that can negatively impact your mental health as you age. In chapter 3, you will find out how you can protect yourself from these external hazards and rejuvenate your brain naturally.
Environment and the Brain
Pollution and poisons in our environment are especially harmful to our brains. Let's examine the substances of greatest concern.
Toxic Substances
Our daily environment can be hazardous to the health of our brains. It is shocking to realize that there are approximately one thousand substances that may cause brain toxicity and accelerate the decline of the brain. Of these one thousand substances, we are in danger of being exposed to several on a regular basis.
These substances cause brain damages in two main ways:
• Acute toxicity occurs when there is a single exposure to high levels of a substance, causing immediate neurological damage.
• Chronic toxicity results from continuous exposure to lower levels of a toxin and can result in long-term negative effects in the body.
Four general categories of substances may contribute to brain toxicity: heavy metals, solvents and fuels, pesticides, and carbon monoxide.
Heavy Metals
Heavy metals that are not metabolized by the body can accumulate in the soft tissue with toxic effect. Heavy metals enter our bodies through food, water, and air. They may also be absorbed through direct contact with our skin. Blood and urine tests can be used to assess levels of heavy metals in the body. According to Dr. Christopher Calapai, DO, "The biggest enemy of the brain is clearly heavy metals. Research going back thirty years has linked heavy metals with Parkinson's, ALS, MS, lupus, Alzheimer's, autoimmune disease — it runs the gamut. And as we pull metals out of the body with appropriate chelation therapy, and we get vitamins, minerals, glutathione back in the body, we start to see significant improvement."
The list below contains four heavy metals that appear in the top ten substances on the 2003 Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) Priority List of Hazardous Substances, compiled by the Agency for Toxic Substances and Disease Registry (ATSDR).
Arsenic. Arsenic is the most common cause of acute heavy metal poisoning in adults. Arsenic is released into the environment by certain manufacturing processes. It can be found in our soil, water, and air. The central nervous system, blood, kidneys, digestive system, and skin are the main targets of arsenic toxicity.
Lead. Children are particularly susceptible to lead toxicity because they are likely to ingest lead-containing substances, such as paint chips. (Paint manufactured prior to 1940 contains lead.) Lead exposure also occurs in the home as drinking water passes through pipes, drains, and soldering materials used on plumbing. Adverse effects of lead exposure occur in the brain, bones, blood, kidneys, and thyroid. A simple blood test can determine lead levels in your body.
Mercury. Mercury affects the cerebellum, the basal ganglia, and the visual centers of the occipital lobe. Among the many conditions linked to mercury in the body is short-term memory loss. Mercury is extremely toxic, and exposure can result in serious physical and neurological problems, and even in death. Mercury is used in thermometers, thermostats, and dental amalgams. Mining operations and paper industries are significant producers of mercury. Until 1990, mercury was added to paint as a fungicide. Mercury is also present in the medicines Mercurochrome and Merthiolate, as well as in some childhood vaccines.
Cadmium. Cadmium is a by-product of mining and the smelting of zinc and lead. Fertilizers with cadmium are used in agriculture and may leach into water supplies. Cigarettes also contain cadmium. Inhalation or ingestion of cadmium can result in damage to the brain, liver, kidneys, bones, and lungs.
Other Toxic Metals
While not considered heavy metals, two other metals pose serious dangers to the brain:
Aluminum. We are exposed to aluminum in abundance. It is found in food additives, antiperspirants, drinking water, automobile exhaust, tobacco smoke, foil, cookware, cans, and ceramics. Researchers have discovered significant amounts of aluminum in the brain tissues of patients with Alzheimer's disease. Although there is no conclusive evidence either for or against aluminum as a factor in Alzheimer's disease, research continues into the relationship between aluminum and such serious brain conditions as dementia and Alzheimer's.
Manganese. Manganese toxicity is a well-recognized hazard for those who may inhale manganese dust. Inhaled manganese is transported directly to the brain and may cause neurological symptoms similar to those of Parkinson's disease. The symptoms of manganese toxicity generally appear slowly, over a period of months or years. Used in gasoline as an antiknock additive, the manganese-containing compound methylcyclopentadienyl manganese tricarbonyl (MMT) was approved for use in the United States in 1995. Manganese may also be ingested by drinking contaminated water and may also cause neurological symptoms.
Solvents and Fuels
Paints, glues, and thinners contain substances that have been shown to cause neurological problems. The usual symptoms of people exposed to these toxins include fatigue, headache, and confusion.
Toluene. Toluene has been associated with long-term neurological problems, such as dementia, balancing and coordination problems, and brain atrophy. Toluene occurs naturally as a component of crude oil and is produced in petroleum refining and coke oven operations. It can also be found in gasoline. Do not be lulled into thinking you have escaped its ravaging effects once you are inside your home, however, because toluene can be found in household aerosols, nail polish, paints, and cleaning agents containing a solvent base.
Sniffing or "huffing" substances containing toluene on a continual basis causes permanent brain damage. Researchers have long studied how exposure to solvents has affected humans. Among the deleterious effects are a wide variety of brain conditions, such as cognition, attention, and memory problems. Depression and anxiety have also been associated with exposure to solvents.
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Excerpted from "Reboot Your Brain"
by .
Copyright © 2013 Gary Null.
Excerpted by permission of Skyhorse Publishing.
All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
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