Rewire Your Brain 2.0: 5 Healthy Factors for a Better Life (2023) - PDF

Advanced Praise for Rewire Your Brain 2.0 “I was delightfully stunned when reading Rewire Your Brain 2.0. It’s rare to find a book that seamlessly integrates the latest findings of neu- roscience with practical tools for overcoming ingrained toxic lifestyle habits that sap joy and happiness. With its blend of c ompelling anec- dotes, fascinating science, and easy-to-implement practices, Rewire Your Brain 2.0 will inspire you to change your life in ways you never before dared or even dreamed possible. Dr. John Arden has g enerously gifted us with a brain-and-life-changing book designed to enhance, heal, and recover our innate sense of w holeness−for body, mind, and spirit. How wonderful!” —Donald Altman, author of The Mindfulness Toolbox, Simply Mindful, and Clearing Emotional Clutter “There is so much in this book. As I read it, I thought that if I only read one book – this would be it! Dr John Arden’s Rewire Your Brain draws together the latest research from neuroscience, psychology, biology and genetics to demonstrate how our minds, bodies, and life- styles interact. Packed with practical ideas, this book details actions we can readily integrate with everyday activity, providing compelling evidence for simultaneously optimizing social, emotional, and physi- cal well-being. Dr Arden eloquently explains and illustrates ways of rewiring our brains and strengthening the mental systems that lead us to long, happy, and healthy lives.” —Jean Annan, PhD, author of 7 Dimensions. Children’s Emotional Well-being, Auckland, New Zealand “This book is wonderfully entertaining and inspiring from the first pages. Neurons and even new neurons, intertwining, find new con- nections in the process of reading this book. Many, weaving into others, as they expand your horizons of new thinking. These new neural connections build powerful ways out of bad habits and atti- tudes that have blocked your life and recreate yourself. You will find this book thoroughly satisfying, accessible, and rewarding.” —Svitlana Grygorieva, PhD, associate professor, State University Odessa, Ukraine “A timely update for those of us invested in keeping our brains and minds healthy. Dr. Arden doesn’t offer brain “hacks” or “hot tips,” but down-to-earth, thoughtful and encouraging advice grounded in neuroscience.” —Sarah McKay, PhD, author of The Women’s Brain Book, Sydney, Australia “Dr. John Arden has that rare ability to take complex biological and psychological science and translate it into easily understood con- cepts for mental health professionals and the general public alike. Not only does he have this translational gift, but he combines it with a creativity and keen insight that takes him to the cutting edge of what we know about healthy minds and healthy bodies. Rewire Your Brain is a powerful synergy of years of accumulated knowledge boiled down to key concepts that are fascinating, intuitive, and practical for you to live a better life. This second edition is a must for anyone who wants to know what key areas are important for overall health, why, and what to do about it, from one of our leading professionals in mental health. —Matthew Dahlitz, Editor-in-Chief, The Science of Psychotherapy, co-author of The Practitioner’s Guide to The Science of Psychotherapy. “In Rewire Your Brain 2.0, Dr. John Arden delivers a masterpiece that’s sure to appeal to both professional and general readers alike. This book combines a fascinating overview of applied neuroscience with tangible steps we can all take to improve our brain and in turn improve our lives in a lasting way. By explaining how and why princi- ples like mindfulness, social connection, and exercise work the way they do, Arden empowers all of us to foster well-being one practical step at a time. A must-have book!” —Jonah Paquette, PsyD, author of Happily Even After, Awestruck, and The Happiness Toolbox “Everything, you, as a professional, need to know about how to nur- ture your most important tool—your brain – for achieving sustainable performance and long-term health, is awaiting you in Dr. Arden’s remarkably well-written book, Rewire Your Brain 2.0. So, what are you waiting for?” —Sefan Falk, executive coach and author of Intrinsic Motivation: Learn to Love Your Work and Succeed As Never Before. “As a clinical neuroscientist, I have always been fascinated by John Arden’s ability to bring the issues of Applied Neuroscience to the ordinary public. The new edition (2.0) of his book Rewire Your Brain allows any person to apply, in his or her real life and real world, the biological basis of a positive behavior and welfare, both for brain and mind. Stimulating and beautifully written, the Rewire Your Brain 2.0, contributes to develop an innovative approach to mental health.” —Tullio Scrimali, MD, PhD, professor of clinical psychology, University of Catania, Catania, Italy, founder and director of ALETEIA, European Scholl of Cognitive Therapy, Enna, Italy “Dr. Arden explains, in a clear, entertaining, and well-supported way, how gene expression can be activated, how we can stimulate neurogenesis, and develop better mental and emotional states fol- lowing a series of behavioral guidelines that become healthy habits. This book is the equivalent of Whitman’s Song to Myself, from the perspective of neuropsychology, a song to freedom to which human beings can aspire. It will add more life to your years. —Juan Francisco Ramírez Martínez CENTRO MEXICANO DE PROGRAMACIÓN NEUROLINGÜÍSTICA “In this engaging book, Dr. Arden teaches us neuroscience with clear, easy to understand and easy to remember explanations and examples. Interwoven throughout the narrative, he offers practical strategies for preserving and boosting, not only brain health, but also total well-being and happiness. Rewire Your Brain 2.0 is a must read!” —Liana Lianov, MD, MPH, president, Global Positive Health Institute Rewire Your Brain 2.0 Rewire Your Brain 2.0 Five Healthy Factors to a Better Life John B. Arden, PhD, ABPP Copyright © 2023 by John B. Arden. 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Library of Congress Cataloging-in-Publication Data is Available: ISBN 9781119895947 (Paperback) ISBN 9781119895954 (ePDF) ISBN 9781119895961 (ePub) COVER DESIGN: PAUL MCCARTHY COVER ART: © GETTY IMAGES | TIMANDTIM This book is dedicated to all those people who have incorrectly assumed that they are beyond help, that their mental health problems can be addressed only medically, and to those who support them. Contents Preface to the Second Edition xiii Part 1 Healthy Brain and Body 1 1 Your Adaptive Brain 3 2 Energizing Your Brain 25 3 Taming False Threats 55 4 Shifting into Action 79 Part 2 The Five SEEDS Factors 103 5 The Social Factor 105 6 The Exercise Factor 129 7 The Education Factor 145 8 The Diet Factor 165 9 The Sleep Factor 195 xi x ii C o n te n ts Part 3 Your Mind-Brain 219 10 Resiliency to Wisdom 221 References237 About the Author 269 Acknowledgments271 Index273 Preface to the Second Edition Since the first publication of this book there have been exciting advances in fields of research that were once assumed irrelevant to the brain and mental health in general. Not only has research in the fields of psychology and neuroscience combined to offer new prac- tical insights about how to improve your brain and mental health, but also the fields of metabolism, epigenetics, and immunology have revolutionized our understanding. This book brings together the practical insights from all these fields and explains how you can apply them to your life. This book is a nontechnical companion to my book Mind-Brain- Gene. Whereas that book addresses how the developments in neu- roscience, epigenetics, and immunology can be applied to therapy, Rewire Your Brain 2.0 is meant to be a down-to-earth book for the general public that describes how to change your brain based on well-researched principles that work. If you want more neuroscien- tific detail, I have added boxes with that information separate from the general narrative. Overall, this book will guide you through the process of rewiring your brain so that you can change how you think and feel for the better. xiii x iv Pre fa c e to th e S e c o n d Edi ti on Each chapter explains key insights from new developments in all these sciences and describes how to apply them to specific areas of your life to help you thrive. I have tried to keep the technical termi- nology to a minimum, but there are some terms and concepts that are worth remembering. In Chapter 1, you’ll learn about the major discoveries that explain how to rewire your brain. You’ll learn how habits are formed, how to increase good habits, and how to stop bad ones. Your brain is always developing new connections between brain cells, called neu- rons, and shedding the old ones that are not being used. You’ll learn how to make new connections that promote good habits and shut off those that support bad habits. These brain changes have been described as “Cells that fire together wire together” and “Cells that fire out of sync lose their link.” You’ll learn to use the acronym FEED to help you remember the steps to rewire your brain. The mnemonic stands for Focus, Effort, Effortlessness, and Determination. By practicing these steps, you can feed and make the rewiring changes described in the rest of the book. You cannot rewire your brain without producing and utilizing energy efficiently. To understand how this works, in Chapter 2 you will learn about your metabolism and the indispensable energy fac- tories in each of your cells. You will learn that your DNA is not your destiny. Your genes are, of course, critical, but the emerging science of epigenetics has shown that genes can be turned on and off with self-care and positive behavior change. You will also learn about how your immune system, and especially chronic inflammation, has a profound negative effect on your brain. The exciting field of psychoneuroimmunology (which stands for the links between your mind, brain, and immune system) will be explained, and there will be suggestions for achieving mental health. We all feel a little anxious or down in the dumps at times. You’ll learn how to reframe these feelings to feel more positive. In Chapter 3, you’ll learn about a part of your brain called the amygdala that can detect threat and is sometimes turned on when there is actually just the miss-perception of threat. Since your amygdala can Pre fa c e to th e S e c o n d Edi ti on xv trigger these kinds of false alarms, you will learn how to keep it in check with another part of your brain called the prefrontal cortex. You’ll also learn about the balance between your sympathetic and the parasympathetic nervous systems: which one becomes excited when need be, and which one helps you to calm down afterward. Also, I’ll explain an evidence-based practice called exposure, which turns off a false alarm so you may approach life courageously and with vitality. In Chapter 4, you’ll learn how withdrawing from the world can worsen sadness and depression. The underactivation of the left prefrontal cortex (PFC) and overactivation of the right PFC are associated with depression. In contrast, activation of the left PFC, which is associated with taking action, contributes to the alleviation of depression and the promotion of positive feelings. I will explain how the techniques of behavioral activation and cognitive restructur- ing can shift your brain activity to your left PFC. You’ll learn how chronic inflammation is strongly linked with depression and prob- lems with thinking clearly. Also, I’ll explain how full spectrum light affects your biochemistry and your mood. You’ll learn how to stay positive and enjoy life with an optimistic attitude. The next five chapters will describe the lifestyle practices that have received the most consistent research toward brain health. They are encoded in the mnemonic SEEDS, which stands for Social, Exercise, Education, Diet, and Sleep. You’ll also learn how these healthy habits enhance your brain’s longevity and how to max- imize a vibrant life free of self-imposed limitations. The SEEDS factors form the foundation and prerequisite for brain health. In Chapter 5 specifically, you’ll learn how people who main- tain positive social relationships live longer and feel more satisfied with their lives and about the brain networks that thrive on social support. I’ll describe how these networks help to build healthy rela- tionships and the empathy critical for your mental health. In Chapter 6, you’ll learn that exercise plays an indispensable role in how your brain rewires and creates new neurons. Exercise is one of the most powerful ways to jump-start the neurochem- istry of neuroplasticity, and one of the best antidepressants and xvi Pre fa c e to th e S e c o n d Edi ti on anti-anxiety techniques that you have immediately available to you. This essential behavior can stimulate neurogenesis, which is a process that can actually grow new neurons in your brain. In Chapter 7, you’ll see how education harnesses your memory skills by wiring together as you learn. Various memory techniques have been used for the last 2000 years, and you can refashion them to enhance your memory capacity. You’ll learn mnemonic devices to make your memory skills work optimally, and how education builds what we call cognitive reserve, to build added connections between neurons that act like a reserve. In Chapter 8, you’ll learn how a healthy diet ensures that your brain creates the right fuel for your energy factories. Your diet also provides the biochemistry for making your brain cells communicate with one another so that you can be calm, energized, and focused. In addition to consuming the right amino acids, vitamins, and min- erals through your diet, you’ll need the correct essential fatty acids to ensure that your cell membranes are supple and flexible enough to enable neuroplasticity. In Chapter 9, you’ll learn how sleep plays a central role in brain maintenance. You spend one-third of your life asleep, and the quality of your sleep determines your health and longevity. You will learn how to achieve a healthy sleep cycle and what the stages of sleep do for your brain. There are stages that help to encode memory, boost your immune system, and wash your brain clean of toxins. In the next part of the book, specifically in Chapter 10, you’ll learn what factors increase your resilience and, despite obstacles, allow you to approach life with a can-do attitude. Research in the field of positive psychology illuminates the role of optimism and healthy ambition and offers antidotes to the narcissistic and material focus that is endemic in contemporary society. In addition, the practice of compassion and nonattachment helps to alleviate needless tension and suffering. Since there are always bumps on the road of life, resiliency and openness allow you to rewire your brain to be flexible and accepting of the rich complexity of life. Pre fa c e to th e S e c o n d Edi ti on xvi i You’ll also learn about the calming yet vitalizing role of nonjudg- mental attention, your prefrontal cortex, and an accepting attitude. The subtle power of parasympathetic meditation can increase your tolerance of stress and your sense of peace. You’ll learn how to increase your ability to be mindfully present and to maintain a sense of connectivity with others and the world around you to thrive. Part 1 Healthy Brain and Body 1 1 Your Adaptive Brain A revolution is occurring in many sciences such as neuroscience, epigenetics, immunology, and psychology to reveal how you can rewire your brain. Since the first edition of this book, new insights have illuminated how your mind, brain, genome, metabolism, and immune system need to be in sync for your well-being. This book brings all this new knowledge together in a down-to-earth manner and explains how to apply it to your daily life and how to get better control of your thoughts and emotions. It was once incorrectly assumed that the brain you were born with was hardwired to function in predetermined ways dictated by your genes. Your brain is not hardwired. Rather, it is soft-wired by experience and how well you take care of it. Neuroscientific research has revealed that the brain is quite plastic. If you think you are stuck with a brain that tortures you with anxiety and depression, you are not. The brain you were born with is modified by your expe- riences throughout your life and is changing all the time. Neither is your behavior or your emotions rigidly determined by your genes. Genes lay out potential vulnerabilities, but they do not dictate your 3 4 Rewi re Yo u r Bra i n 2.0 thoughts, your feelings, or your behavior. You can even turn genes on or off by your self-care behaviors. It was also erroneously believed that all the brain cells you had at birth would be the only ones you would ever possess. The possibil- ity of developing new neurons was thought to be ridiculous. In fact, when I was first studying neuropsychology, my professor said, “You have as many neurons as you will ever have the day you were born; then you lose 10,000 a day!” Yet it turns out that you can grow new neurons in specific areas of your brain under certain conditions. This phenomenon is called neurogenesis. These discoveries shed light on how you can maximize your potential and minimize your vulnerabilities. This book describes how to apply the findings from these fields to rewire your brain so that you can feel calm and positive. By learning these skills, you can improve your ability to focus, face challenges, reach your goals, and yes, even be happy. You can learn to feel less tense, less anxious, and less easily stressed. There are parts of your brain that, when not tamed, tend to overreact and add to needless tension, anxiety, and stress. This book will describe how to get those parts rewired and work for you, not against you. The bottom line is this: how you train yourself to think, feel, and take care of yourself on a regular basis will rewire your brain and allow you to be calm, positive, and focused. This process of rewiring your brain is not merely a taming of parts that are overactivated but also activating the parts that are not. For example, there are parts of your brain that thrive on taking action, and when you do take action you are more likely to enjoy positive feelings. On the other hand, when you sit back passively and wait for positive feelings to emerge, parts of your brain become overac- tive to promote anxiety and depression. Thanks to new discoveries, we now know much more about how the brain works and how you can rewire the parts of it that are out of balance with the others. Think of this book as a manual for a brain tune-up. You will learn to tune up the areas that have become either underactivated or overactivated when you feel down in the dumps, lose your optimism, and look only at the dark side. I will Yo u r Ad a p ti ve B ra i n 5 describe how to activate the parts of your brain that must be bal- anced so you feel positive about your life and see the glass as (at least) half full. You’ll learn to calm down in the face of stress and boost your mood when you’re down. You’ll also learn to improve your memory, have better relationships, and get a good night’s sleep, all of which rewire your brain and thus enable you to be calmer and feel more positive. Nurtured Nature To rewire your brain, the first thing you need to understand is that your brain changes as you adapt to the world around you. Most importantly, you can change how you feel and think. We have moved far away from the old debate about nature versus nurture, and we now know that you are able to “nurture your nature.” Since your brain is not hardwired and is instead soft-wired, your experience and behavior play major roles in modifying your nature. In other words, you change your brain by what you do (Figure 1.1). Figure 1.1 The brain weaving itself 6 Rewi re Yo u r Bra i n 2.0 Your brain weighs just three and a half pounds, yet it’s one of the most advanced organs on the planet. According to the last good count, it has 86 billion brain cells, called neurons, and a trillion glial cells. All these cells are social, meaning that they need to be activated to stay alive. What you do, how you think, and how you take care of yourself changes your brain, just as muscles change when you exercise them. Your brain cells communicate with one another all the time. Most of this communication takes place in the gaps between your neurons, called synapses (Figure 1.2). Since they are not hardwired but instead are soft-wired, new synapses are made when you learn a new skill. This is called synaptic plasticity or neuroplasticity, which you can remember as a rewiring of your brain. Because the syn- apses between your neurons are modifiable, you can acquire new skills and talents, such as how to speak a new language, play the piano, or read. When you repeatedly do something, like ride a bicycle, you use the synaptic connections that support that skill, and in turn you strengthen those connections. When you let the skill lie dormant, you weaken those connections. It’s similar to atrophy and the way your muscles weaken if you stop exercising. In this very real sense, your brain is a use-it-or-lose-it organ. The mantra “Cells that fire together wire together” aptly describes the way your neurons make new synaptic connections so that you can learn new skills. The more you do something in a particular way, such as how to speak a new language, ride a bicycle, or play a piano, the more the neurons fire together and wire together to make it happen again with more ease. Repetition and practice strengthen those synaptic connections. The more the neurons fire together, the more likely it is that they will fire together in the future. A saying that describes the opposite effect is “Neurons that fire apart wire apart.” Or you could say that neurons that are out of sync lose their link, which is the neural explanation for why you forget things. This can happen when you forget to feel anxious or depressed in a certain situation that previously made you anxious or depressed. I use the Yo u r Ad a p ti ve B ra i n 7 Synapse (Axoaxonic) Axonal terminal Node of Ranvier Dendrites Synpse Synaptic Microtubule Synapse Neurofibrils (Axosomatic) cleft Synaptic vesicles Polyribosomes Ribosomes Neurotransmitter Microtubule Receptor Membrane Axon Golgi apparatus hillock Nucleus Myelin Sheath (Schwann cell) Nucleolus Mitochondrion Smooth ER Nucleus (Schwann cell) Microfilament Dendrites Synapse (Axodendritic) Microtubule Axon Figure 1.2 Synapses and neurons 8 Rewi re Yo u r Bra i n 2.0 words made you very lightly because situations do not make you feel this way. They are bad habits that you can break. More about this in Chapters 3 and 4. The more you do something, the more likely it is that you will do it again in the future. That’s why baseball players go to batting practice, golfers go to driving ranges, and piano players practice for hours on end. The same goes for thinking. The more you think about your Aunt Alice, the more she will pop into your mind again and again. That’s what studying for exams is all about. Repetition rewires your brain and grooms habits. When preparing for a final exam, you can earn a higher score by studying early and often. Neuroplasticity makes learning how to be positive possible and how to deal with stress effectively. In fact, if your brain is really hardwired and you were depressed, you would be stuck for life. But this is not true. You are not doomed to suffer. Learning something new is rewiring the brain. By making new connections between thoughts and feelings, you make new synapses between the neurons that encode those ideas and images. LTP vs. LTD Another way to describe the way neuroplasticity works is by the long-term potentiation (LTP) that occurs when the excitation between cells is prolonged and it tends to increase the poten- tial for them to fire together again more easily. This sensitizes and strengthens the connections between the cells to make them more likely to fire together in the future. Thus, LTP pro- motes long-lasting affinity between neurons by reconfiguring their electrochemical relationship. On the sending side of the synapse, the stores of the excitatory neurotransmitter gluta- mate become stronger, while the receptor side of the synapse reconfigures to receive more of it. The voltage on the receptor side becomes stronger in its resting state, which attracts more Yo u r Ad a p ti ve B ra i n 9 glutamate. If the firing between these neurons continues, the genes within the neurons turn on to construct more building blocks for the synapse, which strengthens its activity. Just as the brain needs the LTP mechanisms that strengthen the connections between neurons so that you can improve your memory and learn new skills, it also needs mechanisms that will help it to forget. A process known as long-term depression (LTD) helps you break bad habits. (Note: LTD has nothing to do with the emotional state called depression.) LTD helps you weaken the connections between the neurons that support an old bad habit—like anxious feelings and depressive thinking. This is what is meant by the saying “Cells that fire out of sync lose their link.” When neurons fire together often, they begin to fire together at a quicker rate. They do not require as much energy as before when you were first learning the skill. This leads to increased efficiency because there is more precision in the number of neurons that are recruited to do that skill. For example, when you learn to ride a bicy- cle, you use muscles and neurons that have not yet been linked. As you begin to link them when learning to ride, at first you try to avoid wobbling and falling over. Then, once you learn to ride with ease, less effort is required, and your ride becomes much smoother and faster. The neurons required to fire with their partners have teamed up and wired together. As you become more talented at a specific skill, a greater amount of space in your brain is devoted to making that skill possible. For example, Alvaro Pascual-Leone of Harvard Medical School used measured regional cerebral blood flow with positron emis- sion tomography (PET) to measure specific areas of the cortex. He studied people who are blind who read braille and found that the neuronal networks associated with their reading fingers were larger than the networks for their other fingers and for the fingers of 10 Rewi re Yo u r Bra i n 2.0 readers who can see. In other words, the sensitivity of their reading fingers involved more connections, which used more space. This means that practice enhances neuroplasticity that creates extra space devoted to that skill in your brain. In another example of how the brain rewires, musicians who play string instruments such as the violin were examined to see if their brains had reorganized to accommodate more space. There tends to be little difference between the musicians and the non-musicians in how much space was made available for the fingers of the right hand. However, the area of the brain devoted to the fingers of the left hand showed a dramatic difference because they must be nim- ble and dexterous to make all the fingering movements. The brain space devoted to the fingers involved in fingering was significantly greater in these musicians than in non-musicians. This difference was greatest if the musician had started playing the instrument before the age of 12. In other words, although this use-dependent neuroplasticity occurs during adulthood, it is more dramatic the earlier and the longer that the person plays the instrument. To understand how neuroplasticity works, consider that the age at which you learn a language affects whether you speak with an accent. If you learn a new language while in your 20s, it’s highly probable that you will speak that new language with an accent from your first language. If you learn a new language before age 9, however, you probably won’t have an accent tinged by your first lan- guage. When you learn a new language as an adult, the neurons that have always connected to make specific sounds tend to continue to fire together even when you try to make different but related sounds. For example, if your first language is German and now you are learning English, you may have trouble with the sounds found at the beginning of the words wish and this, because with sounds don’t exist in German. You may therefore pronounce them instead as v and z, which are similar sounds that occur in German. People who speak Japanese often have trouble with the English r and l sounds. The more you speak to people who don’t share your accent, the greater the chance that your accent will fade. For example, both my parents grew up in the Boston area, and a few years after I was born Yo u r Ad a p ti ve B ra i n 11 my family moved to California. My parents gradually lost most of their Bostonian accents as they spoke with people who had moved west from all over the country and with people who had grown up in California. Not only does your behavior rewire your brain; just thinking about or imagining behaviors also can change your brain structure if you repeat those thoughts enough. For example, researchers have shown that simply imagining a session of piano practice contributes to neuroplasticity in the area of the brain associated with the finger movements of playing the piano. Essentially, mental practice con- tributes to the rewiring of the brain. Of course, mental practice is what studying for an exam is all about. But imagining piano lessons without the figure movements is not as effective as with the finger movements. You get the point: Mental practice establishes new con- nections and strengthens them. The bottom line is that repeating a particular behavior strength- ens the synaptic connections that make that behavior possible, and not repeating it weakens the connections. To break a habit, your task is to not strengthen it by repeating it. Eventually it will fade. The less you repeat anxious and depressive thoughts and behaviors, the less they will automatically plague you in the future. Chapters 3 and 4 offer methods to specifically eliminate anxiety and depression. The point here is that cells that fire out of sync lose their link. Neurogenesis One of the important players in both neuroplasticity and neuro- genesis is a growth substance called brain-derived neurotrophic fac- tor (BDNF). It belongs to a family of proteins that enhance your brain cells, called neurotrophic factors. BDNF helps build, grow, and maintain the infrastructure of brain cell connections. Since I described it in the first edition of this book, it continues to be one of the hottest areas of research in neuroscience, and thousands of articles have been written about its amazing growth functions. I call it organic fertilizer because when it’s applied to neurons, it causes them to grow. A vivid illustration of BDNF’s super-fertilizing effect 12 Rewi re Yo u r Bra i n 2.0 occurs when researchers sprinkled BDNF onto neurons in a Petri dish. Those neurons sprouted new branches just like they do in your brain during learning and development. BDNF does its magic in a variety of ways. In general, BDNF prevents cells from dying and enhances their growth and vitality. It works within your brain to activate the genes that increase the production of proteins, serotonin, and even more BDNF. It binds to the receptors at the synapse, triggering a flow of ions that increases the voltage, which in turn strengthens the connectivity between the neurons. BDNF is activated indi- rectly by glutamate and increases the production of internal antioxidants and protective proteins, which stimulates LTP and BDNF. Learning increases BDNF levels. When researchers deprived the brains of BDNF, the brains also lost their capacity for LTP—in other words, learning. Several factors slow BDNF: Chronic inflammation Chronic stress Recurrent depression Marijuana Obesity Sugar Several factors promote BDNF: Exercise Fasting Fewer calories consumed (calorie restriction) Food content (Omega 3) Sunshine and vitamin D As you can see from this list, exercise and diet play major roles in the possibility of neurogenesis. In addition to maximizing the Yo u r Ad a p ti ve B ra i n 13 potential of neurogenesis, both these factors minimize depression, stress, and obesity. Exercise and diet therefore are two of the critical SEEDS factors explained in Chapters 6 and 8. We will explore the neurotrophic factors in Chapter 2. Your Brain’s Brain To rewire your brain, you need to harness the power of your brain’s brain. It is called the prefrontal cortex (PFC) because it is in front of our frontal lobes (Figure 1.3). It makes up about 12% of your brain. In comparison, the PFC of a cat occupies about 3.5% of its brain. The PFC is the most recent addition to human evolutionary development and the last part of the brain to mature in humans. Its development is not complete until the middle of the third decade of life. It provides many of your most complex cognitive, behavioral, and emotional control capacities. Your PFC enables you to focus on, develop, and act on a moral system. It allows you to set aside your immediate impulses and reflect on your long-term goals as well as Dorsolateral Prefrontal Cortex Orbital Prefrontal Cortex Figure 1.3 Prefrontal cortex and its parts 14 Rewi re Yo u r Bra i n 2.0 the needs of others. If your PFC is damaged, you are more likely to engage in antisocial and impulsive behaviors or not engage in any purposeful and constructive behavior at all. One of the most recent evolutionary advances of our PFC is the dorsolateral prefrontal cortex (dlPFC). Yes, this is a mouthful of a term. Dorsal means “fin” or “top,” and lateral means “side.” So think of it as the top and to the side part of your PFC. Your dlPFC is very involved in higher-order thinking, attention, and working memory, the latter so named because it processes what you are working on in mind at any one time. You can usually hold information you’re working on in mind for 20–30 seconds. In addition to the fact that your dlPFC is the last part of your brain to fully mature, it is also the earliest to falter during the senior years of life. When it does falter, it is the reason behind the phenomenon of walking purposely into a room and then forgetting what you intended to do there. The dlPFC is involved with complex problem-solving, and it maintains rich connections with your hippocampus, which helps you to remember things for later. I am constantly “losing” my reading glasses because of it! I will expand on the key role of the hippocampus for memory and education in Chapter 7. Another significant part of your PFC is called the orbital frontal cortex (OFC), so named because it lies just behind the orbs of your eyes. It maintains a closer relationship with the parts of the brain that control threat detection generated by your amygdala. We will get into the role it plays with your amygdala in the detection of threat and anxiety in Chapter 3. Your OFC developed earlier in your life than your dlPFC and is closely associated with socially adept parts of your brain. Highly influenced by bonding, your OFC thrives on close relationships as described in Chapter 5. If those relationships are trusting and sup- portive, your OFC becomes more capable of regulating your emo- tions. In contrast to your dlPFC, your OFC does not falter much in old age. Just to put the OFC in perspective, serious damage to it can result in becoming erratic and explosive. Take the famous case of Phineas Gage, who back in 1848 severely damaged his OFC, which Yo u r Ad a p ti ve B ra i n 15 destroyed his ability to control his emotions. While working on a railroad crew, a steel rod shot through his OFC but left everything else in his brain intact. Gage retained his cognitive abilities but lost much of his ability to inhibit impulses. He had previously been a supervisor who was widely respected for his emotional reserve, but after the accident he became erratic, rude, and unstable. His skull is on display at Harvard Medical School. The take-home point in this chapter is that your brain is amaz- ingly adaptable and changes as you learn new skills. You are in more control of your brain than you think. It is time to exercise that control. FEED Your Brain Now that you have a better idea of how your brain can change, let’s apply a method of rewiring your brain that involves four steps: F: Focus E: Effort E: Effortlessness D: Determination To help you remember these steps, use the acronym FEED, as in feeding your brain. Now let’s examine each step in detail. Focus Focus on the situation, the new behavior, or information that you want to repeat or remember. Focus and attention activate your dlPFC, which alerts other parts of the brain to get engaged. Think of this step as the wakeup call. It is a “This is important!” function. You can’t rewire your brain without alerting the rest of your brain to open the gate for new information. Focus plays an important role in neuroplasticity. Focus gets the ball rolling. Since your PFC is your brain’s brain, it helps to direct the resources to what is important. This contrasts with when you are on automatic pilot, such as when you are driving on a highway 16 Rewi re Yo u r Bra i n 2.0 and talking to your friend in the passenger seat, your attention is directed to the conversation. The conversation is what you will remember, not the trees and the houses along the road. On the other hand, if you talk about what you both notice on the highway, your attention has shifted, and you may remember the physical details of the journey. Yet, simply focusing attention doesn’t ensure that your brain has been rewired. You focus briefly on a hundred thousand experiences every day, and your brain can’t possibly remember all the things you experienced. Think of how many times you paid attention to all the driving challenges such as the intense traffic. Do you remember the traffic lights when you arrive home? No, because they were not important beyond those moments when you had to bring the car to a stop. Focus allows you to pay attention to what’s happening here and now, and this starts the process of neuroplasticity. Effort If you talk about these details of the journey later, you’ll strengthen those memories. If you don’t discuss those details later—that is, you don’t direct your attention to them after your initial focus—chances are those memories will fade. Trying to repeat what you want to remember strengthens the new synaptic connections. Maybe you want to remember a particular area along the road that was your habit of traveling so often you did it on autopilot. Without knowledge of how the brain works, psychologists Robert Yerkes and John Dodson made it clear over a century ago that learn- ing required effort beyond a person’s comfort level. They pointed out that if you are too relaxed or extremely anxious, there is little learning possible. The sweet spot is in the middle of what is referred to as the inverse U (Figure 1.4). It is preferable to be moderately out of your comfort zone to learn and change your brain. Your brain uses a lot of energy when you are trying to learn some- thing new. By observing brain scans, neuroscientists have amassed considerable information about what parts of the brain light up in the scan due to glucose metabolism when someone is think- ing or feeling something new. When you’re making an effort to do Yo u r Ad a p ti ve B ra i n 17 Optimal level QUALITY OF PERFORMANCE Mild alertness Stress Boredom Anxiety Panic Sleep Low High LEVEL OF AROUSAL Figure 1.4 Inverse U something new, the area of your brain associated with that task shows up in the scan as using more energy than other areas. Effortlessness After you have made an effort to learn the new behavior, way of thinking, or feeling, it will take less energy to keep it going as your new habit. Like learning a new tennis swing or how to say hello in a new language, in the beginning it takes focus, effort, and more energy in your brain. But after you make the swing or say hello in Spanish enough times, it becomes wired so that it becomes increasingly effortless. This means that to rewire your brain you’ll have to stay with the new behavior long enough to make it become automatic—effortless. The bottom line is that after a period of time the new skill will come easier. Your brain won’t have to work as hard once you reach this level. Your brain follows natural laws, and the concept of effortlessness is consistent with the Law of the Conservation of Energy. This means that the things that happen are usually things that happen easily to minimize the energy necessary to make it happen. All water flows downhill, not uphill. The deeper the creek, the more water flows in it. 18 Rew i re Yo u r B ra i n 2.0 The same is true for your brain: the more you use certain brain cells together, the more likely you will use them together in the future. It becomes easier and easier. As brain scans illustrate, when you become more proficient in a particular skill, the brain region associated with that skill labors less. This illustrates the fundamental principle of efficiency: what comes easily will be repeated because it’s easy. Determination Once you have developed a new skill—the tennis swing or saying hello in Spanish with the right accent—it will become easier to do each time. But what if you stop doing it? If you haven’t played tennis in 10 years, you won’t swing as well immediately. If you go to Spain 10 years after taking a class in Spanish, you won’t be as fluent as when you were in the class (unless, of course, you have practiced in the meantime). You must continue to do the activity often to effortlessly retain the ability. You’ll certainly play tennis better than if you never played before, and your Spanish will come back more quickly than if you had never learned it before. However, by being determined to stay in practice doing these things, your brain will remain wired to perform them effortlessly. The final step to FEED your brain involves maintaining deter- mination to stay in practice. You must be determined to engage in the activity again and again. Being determined to continue engag- ing in that new habit will not be tiring and painful. If you practice the other three steps in feeding your brain, by the time you get to this one, it remains easy. That’s because effortlessness precedes it. Determination simply means that you must stay in practice, and you’ll complete the feeding process to rewire your brain. Now that you know the four basic steps or principles, we’ll look at how you can apply them in your daily life. In Chapter 3, we’ll discuss dealing with anxious feelings, needless worries, or just plain fear, and in Chapter 4 we’ll address how you can avoid feeling down in the dumps. Chapters 5 to 8 describe the five healthy brain fac- tors to practice daily. The following story illustrates how important it is to make a commitment to stay with all the steps of the FEED formula in rewiring your brain. Yo u r Ad a p ti ve B ra i n 19 Marlee FEEDS Her Brain Marlee asked for an appointment, saying that she was “fed up with being moody.” She complained that she tended to be irritable and easily stressed. “I want to be positive like everyone else,” she said, shaking her head woefully. “I heard that you know how to rewire people’s brains. Please rewire mine.” “It’s not me but you that rewires your brain. Are you willing to do the work?” I asked. “Why can’t you do whatever it is that you do?” she insisted. “They told me that you do hypnosis.” It is true that I was trained in hypnosis, but she needed more to establish a new way of dealing with her emotions. “I’m tired of trying all these gimmicks that are supposed to work but never do.” “When you try something new, how long do you stay with it?” I probed. “Long enough to know that it doesn’t work,” she stated matter-of-factly. I gently prodded her for a clear answer of how long. “Until it gets uncomfortable,” she said, as if that confirmed her strong effort. I explained the inverse U learning curve: how a moderate degree of discomfort is critical to rewire the brain. She had to try to stay with the new behavior until it became effortless to actually learn it. “You must practice doing it until it becomes a new habit,” I told her. “That means that you must do what you don’t feel like doing and continue doing it until it becomes easy to do again.” “Isn’t forcing myself to do something against my nature?” she asked incredulously. “Actually, it’s very natural,” I answered. “That’s how you learn new skills. When you study for a test, you go over material repeatedly until it’s easy to remember it, right?” “No. I just crammed the night before and it worked just fine,” Marlee informed me. “I passed the courses. That’s all I cared about.” 20 Rewi re Yo u r Bra i n 2.0 “Do you remember the subject matter now?” I asked. She shook her head no. I invited her to pick a habit that she wanted to break. “My family says I’m irritable,” she admitted. “Do you agree?” I wanted to know. “When I snap at them, it seems like they deserve it at the time,” she noted. “But later it seems that I was shooting my mouth off and they didn’t really deserve it.” “Do you really want to change or is it your family wants you to?” I asked. “Your motivation is critical. A passive effort just won’t work. With effort, the activation of your brain’s brain can direct all the resources to make the change.” “I’m sick of myself like this,” she said solemnly. “I’m ready to do something.” “Let’s start at the point when you feel the impulse to say some- thing. That’s when you need to interrupt your impulse.” I asked Marlee to stop and focus her attention on the moment before she reacted impulsively. People who have anger outburst problems react immediately through the fast track to the amygdala and lash out with more fight than flight. We will examine this ten- dency in greater detail in Chapter 3. In fact, a time-out step like this is used in anger management classes. Yet here, her task had to go further and focus on being an observer who is detached from the immediacy of the emotional reaction. Instead of the fight part of the fight or flight she needs to focus time to put the brakes on her automatic emotional reactions. Marlee’s PFC had to develop better adaptive strategies to draw attention to what she was angry about rather than to simply express her anger. Next, Marlee needed to make an effort to interrupt her usual impulsive lashing out. She had to act in a way that was different from her usual irritable way she spoke first and lamented later. Instead, she needed to learn to think first and speak later. She espe- cially needed to make this effort when she didn’t feel like it. Marlee needed to repeat this effort enough times so that she eventually found it effortless to do so. She worked with focus and Yo u r Ad a p ti ve B ra i n 21 effort until it was effortless, feeding her brain for several weeks; then she came back in and said, “Well, I don’t have to work as hard on that anymore—I’m getting the hang of it. So, I can take a break, right?” I told her that she needed to continue working on these skills. She needs determination to wire in the new habit. Rather than take a break, she had to continue to regularly work out to stay in shape. It is only by staying determined that she will be able to rewire her brain to keep the new habit. Test Yourself Throughout the rest of the book, we will explore a variety of ways of rewiring your brain. Here is a quick preview quiz that will get to the heart of what’s holding you back from rewiring your brain. 1. To rewire your brain, it’s important to do what? a. Stay within your comfort zone b. Do what comes naturally to you c. Challenge yourself to change your behavior and then stay with it d. Wait until you feel motivated to change 2. What does the acronym FEED stand for? a. Feel good, Exhale, Excite, and Dictate b. Focus, Effort, Effortlessness, and Determination c. Fail, Engage, Encourage, and Describe d. Freedom, Effortlessness, Entertainment, and Doing little 3. If you’re troubled by anxiety, it’s best to do which of the following? a. Avoid what makes you anxious until you calm down b. Take some medication to numb yourself c. Expose yourself gradually to what makes you anxious d. Ask your family to shield you from stress 22 Rewi re Yo u r Bra i n 2.0 4. If you’re down in the dumps, it’s best to do which of the following? a. Hide out from family and friends until you feel up to seeing them b. Dig deep and reflect into why you feel depressed c. Get out of the house, exercise, and engage in activities d. Self-medicate with alcohol and/or sweets to soothe your feelings 5. When you’re trying to improve your memory, it’s best to do which of the following? a. Relax your mind so that you will have enough energy to remember b. Multitask c. Rely on your friends to remember things for you d. Focus your attention, form associations, and review your memories 6. What should you do to improve your diet so that you can more easily rewire your brain? a. Eat large amounts of fried foods, sugar, and processed foods b. Eat three balanced meals per day and hydrate with water throughout the day c. Eat one good hearty meal and consume plenty of caf- feine for energy d. Eat only when you feel hunger pains 7. In old age, what is the best way to boost cognitive reserve and delay or prevent dementia? a. Minimize your mental strain by staying with a routine b. Vary your activities, learn new things, and stay socially connected c. Rest and stay away from any kind of demands d. Have a cocktail in the evening and ruminate about the past Yo u r Ad a p ti ve B ra i n 23 8. Five habits that form the foundation for a healthy brain can be remembered as planting SEEDS. What does this acronym stand for? a. Safety, Escape, Exit, Distance, and Soothingness b. Sensation, Entertainment, Ecstasy, Distraction, and Slipping away c. Stifle, End, Execute, Don’t, and Stonewall d. Social, Exercise, Education, Diet, Sleep hygiene 9. To build a resilient brain, you should do which of the following? a. Cultivate optimism, inoculate yourself with manage- able stress, and challenge yourself b. Make pessimism your default mode so that you will never be surprised c. Avoid stress at all costs d. Save your energy for times of need 10. A mindful brain does which of the following? a. Shuts down, checks out, and is otherwise mindless b. Is in the here and now, savoring every moment and sensation c. Looks for constant distraction from the stress and strain of the moment d. Is holier than thou I will explain in detail what you need to know to answer these questions in the remaining chapters of this book. 2 Energizing Your Brain Y ou need energy to rewire your brain. And because your energy is not immaculately conceived, you must learn to make it effi- ciently. This chapter explains how energy is indispensable to life and the functioning of your brain. Since your brain depends on energy to function, I will describe how you can ensure that you make enough of it to keep your brain healthy and your mind sharp. Without energy you can’t turn on and off your genes. That’s right, your genes are not always on. In fact, your DNA does not rigidly determine your destiny. The emerging science of epigenet- ics has shown that your self-care plays a major role in determining which genes are turned on or off. We will also explore how energy, gene expression, and your immune system combine their effects in your brain functioning. When your energy is in short supply or misused your immune system can work against your brain. These malfunctions happen when you don’t take care of yourself and can trigger chronic inflammation that results in depressive moods and brain fog. 25 26 Rewi re Yo u r Bra i n 2.0 The differences between people based on their lifestyles could not be more dramatic than between two brothers who shared the same DNA. Sam and Tyler are identical twins, but they diverge dramatically in their lifestyles. Sam describes himself as a home- body. He rarely ventures out into the community other than to go to the supermarket to buy steaks and burgers to barbecue. He enjoys sitting in his den where he watches sports most days and evenings. During the winter it was football, spring basketball, and summer baseball. He even watches games that he recorded. Tyler is anything but a homebody. Instead of watching sports all day, he is an active member of various community groups. He, too, enjoys sports. But instead of being a passive spectator, he is an active participant in various city leagues, baseball, and tennis. At age 48, he looks 10 years younger, in contrast to his twin brother, who looks 10 years older. Tyler is also 40 pounds lighter than Sam and describes his condition as quite fit. Sam describes himself as looking like he lived the good life. Yet Sam is plagued by high blood pressure and type 2 diabetes. Tyler is always taking classes in subjects ranging from geology to art at the community college. For his part, Sam says that he is retired. When Tyler asks him what he means by retired, Sam replies by saying, “It means that I can watch the grass grow.” In their ongoing playful and often whimsical and teasing ban- ter Tyler once asked, “Do you mow that grass?” Sam laughed and answered, “I told you I was retired!” Once Tyler made a deal with the teenager next door to Sam not to mow his lawn that week as scheduled. The teenager agreed to come to Sam’s with his mower and accept money for not mowing. Sam became irate. Tyler said, “Not to worry. I will do the job,” as a tease. After he finished mowing the lawn, he paid the teenager in front of Sam. The teenager and Sam exchanged a glance with a shoulder shrug and then shook their heads that Tyler needed psychologi- cal help. Playing along, Tyler laughed, then thanked Sam “for the opportunity for some exercise. The gym was closed.” Sam’s wife was watching the entire scene and turned to Tyler with her eyes rolled. She knew quite well that Tyler’s teasing joke was on her husband. E n e rg i zi n g Yo u r Bra in 27 “Where’s all this crazy energy coming from?” Sam asked his brother. “What happened to yours? You aren’t the same brother I grew up with.” Though these brothers started out with the same DNA, they became dramatically different in attitudes, activity levels, and over- all health. The obvious difference was their lifestyle. Tyler plants and cultivates the five healthy factors encoded in the mnemonic SEEDS (which stand for Social, Exercise, Education, Diet, and Sleep) on a daily basis. Sam seemed resigned to the belief that his energy was retired and rarely engaged in any of the SEEDS factors. Mitos—Your Energy Generators Where did Tyler’s energy come from? Is it prana or chi? Is it some kind of spiritual energy that we can never totally understand? When producing and harnessing the energy to rewire your brain, we don’t need to get lost in those philosophical debates. The answer is right in front of us. Your brain is a biological organ, and it runs on biological energy. So, if you hope to rewire your brain, you should understand how to make and keep energy working efficiently in your brain. The first thing to appreciate is where and how energy is made. Like all your cells, brain cells contain energy factories called mito- chondria. Cells contain from 1000 to 2500 mitochondria. To make them simple to remember we will call them mitos because they are mighty! See Figure 2.1 for an image of a cell and its mitos. They pro- duce your energy, called adenosine triphosphate, better known as ATP. To make ATP simple, think of it as All The Power. ATP plays an indispensable role in determining whether you live or die. Consider that the poison called cyanide will kill you because it immediately kills your mitos. Without your mitos—no ATP, and you die. Mito health and their product, ATP, determine whether you can read this sentence, rewire your brain, and maintain mental health. While Tyler generates a lot of it, Sam is retiring his mitos. 28 Rewi re Yo u r Bra i n 2.0 Nucleolus Mitochondrion Nucleus Cytoplasm Cell membrane Golgi apparatus Inner membrane Cristae Outer membrane Matrix Figure 2.1 A cell and mitochondria Every day your mitos make two hundred trillion trillion ATP mol- ecules. Another way to grasp the volume and importance of your mitos is to consider that you produce and recycle your body weight in ATP. The greater your energy needs and the greater the demand on your mitos. This also means that there are adverse consequences when ATP is in short supply. One of the first places you feel loss of ATP is in your brain. E n e rg i zi n g Yo u r Bra in 29 Though it weighs a mere three and a half pounds, your brain is among the highest energy consumers in your body. So it is no coin- cidence that your brain cells contain among the greatest number of mitos. There are approximately 10 million billion mitos in your brain. To put this astounding number in perspective, consider that your brain uses 20% of your body’s energy, and your synapses use 80% of that energy. This means that much of that energy is devoted to fueling synapses for neuroplasticity. In other words, without enough energy you can’t rewire your brain. Mobile Mitos Neuroplasticity is facilitated by mobile mitos. They travel on miniature tracks, called microtubules, which are like small tubes within your neurons. This mobility allows your mitos to get energy delivered to where the rewiring action is, at your synapses. In other words, mobile mitos provide the energy to rewire your brain. You may wonder why you have so little energy, cannot think clearly, or cannot maintain a positive mood. If you are already in poor health, you may be accelerating the death of your mitos within your brain cells. You need to maintain your health to give your mitos a chance to help your brain have the capacity to think clearly and produce positive moods. Just as it is senseless to drive a car without fuel, it’s even more senseless to hop in the driver’s seat without enough brain energy to drive carefully. Like the engine for your car that needs the right fuel for combustion, to generate energy your mitos must take in the right balance of raw materials to produce ATP. For your car it is refined gasoline, and for your mitos it is oxygen from breathing and glucose, which is derived from the food you eat. Those raw materials travels through your bloodstream to all your cells, at which point the 30 Rewi re Yo u r Bra i n 2.0 hormone insulin helps get the glucose into your cells so that your mitos can begin to generate ATP. Without this energy your brain cells black out. Not only do you need the right balance of raw materials for your mitos to produce ATP, but you need to use up the ATP to keep your mitos healthy. Unlike your car that you leave in your garage for a month before driving it again, your brain cannot take a break for one month. Your body needs to use the energy to make more. This is a use-it-or-lose-it must. You must use the energy that you make so that you can make more of it. In other words, exercise is also critical for the health of your mitos. These two self-care factors of exercise and diet will be explained in more detail in Chapters 6 and 8. Unhealthy mitos don’t just produce less energy. They cause ill health. Consider that if you eat mostly junk food and fail to exercise, your mitos will generate excess free radicals, which damage your cells. Like a nuclear meltdown that leaks out radiation and destroys the power plant, free radical damage can kill your mitos from which they leak. In other words, eating junk food and failing to exercise blow out your mitos and destroy the cells they inhabit. This damage to your mitos and cells means you lose energy, feel lethargic, can’t think clearly, and may even become depressed. This is one of the reasons that Sam looked 10 years older than Tyler and had much less energy and motivation. Leaky Mitos—Free Radical Toxicity One way to understand how energy is produced is to think of mitos as following the principles of a hydroelectric dam. As water fills a reservoir within the dam, pressure builds up so that the water is forced out through a channel to drive turbines to create electricity. Just like dams, mitos use pressure so that energy is released from electrons within the pump. The reac- tions from the released electrons are used to pump protons through the membranes of mitos to generate biochemical reac- tions culminating with the final product, the synthesis of ATP. E n e rg i zi n g Yo u r Bra in 31 Just as a dam runs the risk of potential leaks, so too can mitos leak. For mitos the main source of leakage is referred to as reactive oxygen species (ROS), a type of free radical. Free radicals develop when unmatched electrons leak from your mitos and then steal available electrons from the lipids in cell membranes. Damage to your cells from excessive free radical leakage occurs when you overeat (especially junk food) and fail to exercise. See Figure 2.2 for the difference between a healthy mitochondrial and an unhealthy mitochondrial. MITOCHONDRIA Healthy mito Unhealthy mito Produces Little Produces Energy Produces LOTS of Produces Very FEW Energy LOTS of Harmful Harmful Free Free Radicals Radicals Figure 2.2 A healthy mitochondria and unhealthy mitochondria Normally, mitos have a shelf life of a few days to a few weeks. Your mitos need to recycle to keep the healthy ones working well and get rid of those that are unhealthy. Their two principal recycling methods are mitophagy (killing off old and damaged mitos), and bio- genesis (the birth of new mitos). These recycling methods work to ensure that underperforming mitos (that are no longer mighty) are killed off. This critical recycling function is facilitated by exercise. When the old and damaged ones are removed, there is room left for the healthy mitos to thrive and new ones to be born. However, this recycling process does not work efficiently if you are suffer- ing from chronic health conditions, in which case low-functioning mitos spew out free radicals and as a result speed up the damage to your brain cells. 32 Rewi re Yo u r Bra i n 2.0 This recycling loop can also break down when you, like Sam, don’t exercise and eat too much of the wrong foods, such as those with excess calories, simple carbohydrates, and bad fats. This is because overeating increases the half-life of weak mitos so that they remain pooled together. These weak and inefficient mitos are even harder to kill off by mitophagy because you are not exercis- ing. Consequently, the weak mitos produce less ATP and more free radicals than healthy mitos. Metabolism All the energy production, recycling, and the resulting biological activity to keep you alive is referred to as your metabolism. It encom- passes all the work that your body does to maintain the health of your mitos and the ATP they produce which are used by all your organs. Depending on where in your body those cells are located, ATP fuels that organ’s metabolism and its interdependence with your other organs. Since your metabolism and the energy are inter- related, one doesn’t happen without the other. The total of all the work and the energy you expend to keep yourself alive represents your body’s metabolic rate. Impaired brain metabolism leads to many types of dementia such as Alzheimer’s and Parkinson’s diseases. Metabolic disorders lead to many precursor symptoms of dementia such as cognitive and memory difficulties called mild cognitive impairment (MCI). MCI is on the rise because the Western lifestyle of an unhealthy diet, lit- tle to no exercise, and being overweight is quite destructive to the metabolism of the brain. If you, like Sam, are one of the millions of people caught in the pandemic of overeating, obesity, and lack of exercise, expect that your brain metabolism will suffer. Though your brain cells require considerable ATP for their energy needs, fat cells do not and they tax your metabolism. If you gain extra fat cells, especially if your body mass index (BMI) exceeds 30, your energy production will decrease and so will the number of healthy mitos in your brain cells. Worst yet, excessive weight contributes to metabolic disor- ders, chronic inflammation, and even brain shrinkage. This means E n e rg i zi n g Yo u r Bra in 33 that as your fat cells increase, your brain cells can decrease. The brain areas most vulnerable to damage and shrinking are your PFC and hippocampus. This damage results in problems making decisions and remembering information necessary to make those decisions. Metabolic syndrome is a growing societal timebomb on our health care system. Don’t be part of it. Metabolic syndrome has been esti- mated to burden around 20–25% of adults in the world, and the numbers are increasing. The most common symptoms metabolic syndrome include: High blood pressure High levels of LDL cholesterol A large waistline This constellation of destructive health conditions leads to type 2 diabetes, which leads to type 3 diabetes, also called Alzheimer’s disease. The question you must ask yourself is: Do you think that you can rewire your brain with all these corrosive things occurring in your brain without changing your lifestyle to prevent them? The answer is that regaining your health is a prerequisite to rewiring your brain. Consider that your brain is one of the highest energy consumers in the body. If your blood sugar rises too high, it is not only toxic for brain cells but also impairs the ability of your pancreas to produce insulin to deal with the flood of glucose. The effects of metabolic syndrome blunt the receptivity of insulin receptors on cells, which results in type 2 diabetes. No longer will your metabolic system be able to deal with the excess sugar. As cells corrode, you have little energy, making it difficult to think clearly and maintain a positive mood. The bottom line is that you must maintain metabolic health for the sake of your brain or it will suffer. You need plentiful healthy mitos in each cell not only in your brain but also throughout your body. The energy produced by them is indispensable for the capacity to think clearly and enjoy positive moods. For healthy mitos you must engage in all the SEEDS factors daily, as detailed in Chapters 5–9. 34 Rewi re Yo u r Bra i n 2.0 Genomic Plasticity Until recently many people mistakenly believed that their DNA was their destiny. All too often, I have heard patients say that their depression or anxiety was the result of bad genes. Some said, “There is no use in trying to change because bad genes made my bad brain.” Some even thought that their personality was programed by their genes. This kind of simplistic thinking has been called genetic astrol- ogy by geneticists. Don’t buy into this self-defeating silliness. It is antiscience, and believing in it will undermine your motivation to make the lifestyle changes necessary for your brain health. To understand why you aren’t doomed by your genes, we need to first dispel a few myths. There is no simple one-to-one correspon dence between your genes and mind. Genes, by themselves, do nothing like that. So, what is a gene, anyway? It is a misnomer to say that there is a gene for this type of thinking or a gene for that type of emotion. To understand the role that your genes play in your life you need first to understand that a gene is a section of your DNA that contains the recipe for a protein. To be more precise, a gene codes for an amino acid which then combines with other amino acids to make a protein. So, genes do not make personalities, prevent you from being happy, or love the color purple. If genes did such things, Tyler and Sam would share personality characteristics. Again, genes simply contain the recipe to make proteins. Chromosomes, DNA, and Genes When researchers discovered the entire DNA–protein complex under a microscope, it appeared purplish-brown, so they named it a chromosome, from the Greek khroma meaning “color.” You have 23 chromosomes in each cell. The stuff of chromosomes includes DNA and genes. Your DNA is composed of four nucle- otides: adenine, thymine, cytosine, and guanine. These are all arranged in an order that is uniquely you. They are commonly E n e rg i zi n g Yo u r Bra in 35 referred to by letters that are abbreviated from the nucleotides as A, T, C, and G. The identification of a particular gene is three letters long, located within your DNA. They can be adjacent or more often separated by many spaces and organized in triplets. To make a protein, the triplet sequence of nucleotides that rep- resents a gene must be copied by DNA’s cousin molecule, RNA. Genetic information is sent via messenger RNA to the protein factories in your cells called ribosomes. From the beginning of your life until death, your body grows new cells to replace old ones. In doing so, cells divide and copy your entire genome, which includes all your chromosomes with your DNA and genes. The two strands of the double helix separate and serve as a template for the creation of another strand to match it. The new double-stranded DNA has exactly the same base sequence as its parent molecule. Each of your cells contains all the three billion base pairs of DNA—half inherited from your father, half from your mother—which combine to produce your unique sequence, referred to as your genome. We know a lot about our DNA thanks to the Human Genome Project. It was a decades-long international effort involving 32 institu- tions and 442 scientists at a cost of $288 million. Prior to this project we erroneously believed that humans possessed 100,000 genes. It was surprising to discover that we have only between 20,000 and 25,000 genes. To put this humbling discovery in perspective, a round- worm has roughly 20,000 genes and a grape has 30,434. Since we are much more complicated creatures than worms or grapes, why don’t we have more genes? Surely, if individual genes make particular traits and since humans have more traits than worms and grapes, wouldn’t we have more genes? What is the answer to this puzzle? Part of the answer to these questions came from the project’s most surprising discovery: that only 2% of human DNA can be described as genes. The remaining 98% was initially called junk 36 Rewi re Yo u r Bra i n 2.0 DNA because no one knew what what it did. More recently we discovered that it was wrong to refer to this 98% of our DNA as junk. It is now referred to as noncoding DNA because it does not code for protein and therefore cannot be described as genes. If only 2% of your DNA can be described as genes, then the question we must ask is what does the noncoding remaining 98% DNA do? One significant clue is that we have far more of noncoding DNA than any other living creature. We now know that the expression of your genes is far more variable and flexible than other living creatures because your noncoding DNA plays a role in how your genes are used in response to the context of your experience and behavior. And it turns out that the noncoding DNA does all sorts of things, including helping turn on and off genes. This makes your behavior far less determined by individual genes than any other species. Yes, genes are indispensable for the instructions to make proteins, but your behavior and experience cannot be explained by your individual genes. This means that your noncoding DNA endows you with a great degree of flexibility in how your genes are expressed. In other words, your self-care behavior can change which genes are expressed and which genes are not. As the scientific community learned that the human genome is far more complex than expected, a new science called epigenetics emerged to explain how our genome is quite plastic. Epigenetics, meaning “above the genome,” explores genes expression. It has revo- lutionized biological science, health care, and our understanding of how we came to be a species with complex mental capacities. Thanks to epigenetics, we know a lot more about how and under what circumstances different genes are turned on (expressed) and some are turned off (suppressed). You may have a particular gene, but it may not be expressed because your environment and behavior suppress that gene or other genes that interact with it. Epigenetics explains how genetic material can be activated or deactivated in different contexts, such as your self-care behaviors. What’s more, genes are expressed or suppressed, not by a simple on-or-off switch but more like a dimmer switch that adjusts in response to your diet, whether you exercise, sleep well, have quality relationships, and manage your stress effectively. E n e rg i zi n g Yo u r Bra in 37 The interactions between your genome, behavior, and environ- ment change your brain for better or worse. For example, the inter- actions between stressful environmental conditions, not getting enough quality sleep, and engaging in other unhealthy lifestyle hab- its adversely influence the expression of your genes, which can have detrimental effects on your brain, emotions, and clarity of thought. Your brain possesses an array of short- and long-term memory capacities that in part are facilitated by epigenetic mechanisms for the regulation of neurotransmitters, hormones, and immune system molecules. If you believe that your environment is threatening, genes may be expressed to ramp up your sympathetic nervous sys- tem’s fight-or-flight response or the neuroendocrine (hypothalamic pituitary adrenal [HPA] axis) stress pathways. Psychologists have long pointed out that people who were neglected, abused, or insecurely attached to their parents tend to tolerate stress less. Now we know that epigenetic mechanisms are at play. For example, researchers have shown that people who are provided a nurturing environment early in their life turn on genes that give them greater stress tolerance than those who are neglected because those genes are turned off, leading to less stress tolerance. As a result, people who were nurtured early in life have a better thermostat for stress. They have an innate ability to turn off the stress response without even trying. They are essentially more durable in stressful situations. This thermostat for stress is provided by the epigenetic products of proteins, which are cortisol receptors. Neglected people are less likely to produce proteins associated with cortisol receptors. They have fewer cortisol receptors, which means that their neuroendocrine system has less of an ability to turn off their HPA axis, which produces cortisol. As a result, they may, at times, tend to experience uncontrollable stress. If you are worried that you are one of those people who were neglected or abused and as a result suffered from epigenetic effects that I just explained, please do not feel stuck or doomed. Don’t forget that genes can be turned on and off throughout your life. Following the recommendations in this book will help make up for these deficits. 38 Rewi re Yo u r Bra i n 2.0 Neurotrophic Factors—Your Brain Fertilizers Growth substances play a significant epigenetic role in the health of your brain. A variety of substances cells called neu- rotrophic factors, protect and grow new brain cells and they appear to be activated through epigenetic mechanisms. Early nurturance is associated with the epigenetic expression (turn- ing on) of a transcription factor called nerve growth factor (NGF), which binds to the cortisol receptor gene to increase cortisol receptors. In contrast, neglect or child abuse is asso- ciated with turning off NGF. As a result, neglected people tend to produce fewer cortisol receptor proteins in their hip- pocampus. Their stress response systems become hyperactive (harder to turn off), predisposing them to anxiety and fearful- ness. For example, women who were neglected as babies tend to become stressed-out and neglectful mothers, too, continu- ing the cycle of neglect through the alteration of the NGF gene. They may even have offspring with the same alteration to their NGF gene. You met brain-derived neurotrophic factor (BDNF) in the previous chapter, where I described how it plays a significant role in neurogenesis, neuroplasticity, and overall brain health. Unfortunately, some epigenetic influences of early life adver- sity can suppress the BDNF gene. The brain areas associated with this impairment include the hippocampus and prefrontal cortex, which are critical for higher cognitive functions such as planning, memory, and goal-directed behavior. Fortunately, you can stimulate the release of BDNF by aerobic exercise as I describe in Chapter 6. Insulin-like growth factor (IGF-1) decreases blood glucose levels by helping deliver it to cells so that their mitos can generate energy. IGF-1 contributes to brain growth and can be epigenetically facilitated by prosocial circuits in the brain. E n e rg i zi n g Yo u r Bra in 39 Though in Chapter 5 you will learn how the social factor is critical for overall brain health, the point here is that positive social experiences affect gene expression important for the health of your brain. People who received nurturing tend to build resiliency net- works in their brain such as more GABA receptor sites, which act to reduce stress and anxiety. They also have diminished lev- els of stress neurochemistry. In general, well-nurtured people are less anxious and more engaged in their environments, even during fear-inducing situations. Telomeres—The Aglets on Your Chromosomes In closing out this section on the plasticity of your genome, it is important to address one of the ways your genes can be damaged. Your chromosomes are capped with noncoding DNA called telo meres, from the Greek “end.” Often analogized as aglets of shoe- laces that protect them from unraveling, the telomeres protect your chromosomes (i.e., DNA) from damage. This vulnerability leaves genes more exposed to mutation (damage) and results in accelerated aging as well as the increased risk of many illnesses. Your cells are constantly dying and being replaced by new ones through a process called cell division. When cells divide to make new ones, telomeres shorten. This is one of the reasons telomere length serves as a biomarker for health and longevity. Your behavior can impair your chromosomes by accelerating the shortening of your telomeres. Serious illnesses and poor self-care behaviors shorten telomere length. The SEEDS factors may protect your genes by enhancing the health of your telomeres. They do this by promoting the release of an enzyme called telomerase that protects telomeres by adding nucleotides to telomeres. Whereas oxidative stress reduces telomer- ase activity, antioxidants increase it. Healthy self-care behaviors pro- tect telomeres; not engaging in self-care shortens your telomeres. 40 Rewi re Yo u r Bra i n 2.0 Factors That Shorten Telomeres Metabolic disorders Cardiovascular disease Smoking Obesity (more than smoking!) Type 2 diabetes Social isolation Poor diet No exercise Poor sleep Alcohol and other drugs Chronic inflammation Tyler and his brother were illustrating what a difference in behavior makes on a person. Lifestyle practices such as the SEEDS factors increase the activity of telomerase. The Immune System in Your Brain You may wonder why I have included a section on the immune system in a book on the brain health. Your immune system is not segregated from your brain to other parts of your body. It has a dra- matic effect on your capacity to think clearly and to maintain energy, motivation, and a positive mood. In fact, you have specialized cells in your brain that are responsive to immune cells in other parts of your body. When your immune system works well, it differentiates your cells from those that do not belong in your body. Your immune system, therefore, is by nature self-identifying so that it can protect you from what is not you. It keeps your brain safe, just like the rest of your body, from foreign substances. Normally, your blood–brain barrier protects your brain from harmful substances, but when there are E n e rg i zi n g Yo u r Bra in 41 threats to other parts of your body, the distress signals are sent to your brain. Because of this interaction, when your immune system is not working well, such as when it is turned on inappropriately, you can have trouble thinking clearly and may suffer from depression. To get a better idea how your immune system works, let’s first take a broad look at how it is organized. You have two basic divisions of your immune system: the innate and adaptive subsystems. As the name suggests, your innate system contains all the defenses that you are born with. It protects cells in your body from the threat of invaders that do not belong in your body and marshals an immediate defense. But its weapons are not crafted to meet the specific char- acteristics of a unique threat. That comes later with the adaptive immune system, which provides a more sophisticated and precise protection from specific new threats, such as viruses that you never encountered before. Your adaptive system is so named because it adapts to new threats that you encounter throughout your life. It manufactures T and B cells, the latter of which create antibodies that develop in response to learning about the new invaders such as viruses. It also protects you from threats by charging up your innate system to fight harder. Without the innate immune system, your adaptive immune system does not possess the foot soldiers to do the majority of the heavy lifting needed to fight off invaders. Without your adaptive immune system, the innate immune system is not sophisticated enough to fight off more complicated invaders such as the COVID virus. Inflammation is the universal response of your immune system to any danger to your body. Inflammation gets its name from the red flame-like swelling and the heat that occurs with an injury or infection. Think of inflammation as the yellow tape strung around a crime scene that protects it so that investigators can get in without anyone else coming in and messing with the evidence. Just like a crime scene, the purpose of inflammation is to restrict the area to only immune cells so that they can come in to inspect and deal with the danger. Inflammation promotes the opening up of blood vessels to let plasma (the fluid part of blood) bring immune cells into the damage area. This is why there is swelling around a wound. 42 Rewi re Yo u r Bra i n 2.0 Your innate immune system uses heat, such as fever, along with inflammation because microorganisms do not like it hot. Your immune repair cells do like it hot because it helps speed up your metabolism and enables wounds to heal faster. Meanwhile, the pain associated with inflammation motivates you to protect the area. Together with the loss of function, swelling, and heat, the pain gives you good reason to slow down and cease your activities so that you have time to heal. When all these parts of your immune system are working well, they not only keep you alive but also protect your brain. However, malfunctions in your immune system can damage your brain. For example, while too little inflammation during an infection leaves your body defenseless, chronic inflammation can break down body systems and damage your brain. Chronic inflammation is associated with many diseases, including heart disease. Your brain is particu- larly sensitive to chronic inflammation, and its effects can lead to depression, cognitive deficits, and dementia. Inflammatory Messaging The language of your immune system is provided by cytokines. From the cyto, meaning cell, and kine, meaning movement, cytokines are proteins that move around your body conveying information about the state of your health and where immune cells must go to fight off invaders to protect your health. Pro- and anti-inflammatory cytokines come in many flavors and are released by a variety of immune cells, including macrophages, Helper T cells, and Killer T cells. Your brain contains its own immune system response cells called glia cells (e.g., microglial cells and astrocytes). They release either pro-or anti-inflammatory cytokines depending on the challenges to your body. Microglia make up 6–12% of all the cells in your brain. They constantly monitor for poten- tial threats to your brain by foreign invaders. When they iden- tify danger, microglia release pro-inflammatory cytokines that E n e rg i zi n g Yo u r Bra in 43 romote inflammation in your brain. Sometimes the danger p signals are psychological, such as when you are going through a stressful period, at which time your microglia cells may release pro-inflammatory cytokines. Chronic stress and ill health prime microglia so that they release pro-inflammatory signals more eas- ily when they encounter danger again. In other words, chronic stress makes it more likely that the immune cells in your brain will be activated in the future and promote inflammation. For their part, astrocytes also play a major role in your immune system in your brain by functioning as a point of interaction between cytokines and neurons through genetic transcription and synaptic plasticity. Astrocytes exchange signals with neurons, detect and react to immune signals, and release pro-inflammatory cytokines that signal peripheral immune cells. Astrocytes can perpetuate a chronic inflammatory spiral in response to the excessive release of inflammatory signals from microglia. Inflamed Brain Chronic inflammation is distinct from acute inflammation such as when you have an infection. Whereas acute inflammation is short-lived and is important for tissue repair should you get injured, chronic inflam- mation is destructive. It leads to a variety of pathological conditions such as depression and autoimmune and neurodegenerative diseases. To understand how chronic inflammation is destructive to your brain, consider how it blocks energy from the areas that are inflamed. When your immune system is turned on in the absence of a foreign invader, it may even attack your own body, fighting your cells including those in the brain as if they are invaders. Chronic inflammation can make you feel and behave like you are sick. Your brain suffers, and so does your mental health. Depression associated with chronic inflammation has been dubbed sickness behavior. For example, Sandra came to see me with complaints of low energy, difficulty thinking clearly, and mild depression. This is 44 Rewi re Yo u r Bra i n 2.0 because those people like Sandra are afflicted with chronic inflam- mation. People like Sandra feel and behave as if they are ill. She was overweight and prediabetic. Her consistent complaint was feeling tired all the time, disruptions to sleep, and decreased social interests. She spent the evening eating comfort food, which was essentially composed of simple carbohydrates. Her anhedonia and deficits in learning and memory spilled over into her work environment. The downward spiral of depressive moods and lack of insight spread into poor job performance, which eventually made her feel worse after receiving a scathing evaluation from her supervisor. Since Sandra felt ill, she acted as if she were ill. Her sedentary behavior and overeating inadvertently made her more depressed and feel even more ill. She thought that she needed to recoup or get over the illness by resting. Yet her sedentary behavior perpetuated chronic inflammation, which made her depression and cognitive fog worse. When she made a brief attempt to pull out of the spiral, she initially felt worse over the short term. So she stopped trying to break bad habits. Had she persisted long enough she would have discovered that over the longer term she would have felt better as she gradually decreased her chronic inflammation. Symptoms of Sickness Behavior and Chronic Inflammation Anhedonia Depressed mood Cognitive deficits Loss of social interest Fatigue Low libido Poor appetite Somnolence Pain sensitivity Anxiety E n e rg i zi n g Yo u r Bra in 45 Overall, chronic inflammation can result from poor self-care practices, obesity, and/or metabolic syndrome. The combination of all of these disorders contributes to insulin resistance, the risk of type 2 diabetes, and cardiovascular illness, which all contribute to more chronic inflammation in your brain. These combined effects to your brain are associated with psychological disorders such as cognitive impairments, anxiety, and depression. One of the ways that chronic inflammation causes cognitive and mood deficits is by disturbing synaptic strength. There are high concentrations of receptors for pro-inflammatory cytokines located in your prefrontal cortex and hippocampus that can potentiate cog- nitive impairments, including poor memory and decision making. Excessive pro-inflammatory cytokines especially in your hippocam- pu

Rewire Your Brain 2.0: 5 Healthy Factors for a Better Life (2023) - PDF

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