Your Brain is a River, Not a Rock Quotes

“The frontal area creates abstract symbols for the concrete pictures generated in the back of the brain. So even though children’s behavior will be the same — they respond as you or I would — they are actually using different parts of their brains. Children live in a concrete world and make decisions based on what they see in front of them. Figure 3.4 Areas of the brain active during tasks in children and adults. Who is in control? Nature’s built-in program links individual neurons found at birth. Does nurture also influence brain connections? Yes. Nature and nurture work together to develop brain connections. The rate and extent of neural exuberance and neural pruning is affected by food, level of stress, and types of experience. The effect of daily experience on brain functioning is another important dimension to explore.”
― Frederick Travis Ph.D., Your Brain Is a River, Not a Rock

“Figure 3.3 Astrocytes maintain the structure of the synapses. In addition, the astrocytes maintain the 20 nanometer wide space between the axon terminal from one cell (output) and the dendritic spines of another cell (input). This space is called the synapse. How is this very thin space maintained? Why doesn’t the axon terminal float away? Or glide into the dendritic spine? Notice in the figure the ends of the astrocyte envelop the synapse and maintain its integrity. The astrocyte both encircles the axon terminal and the dendritic spine and maintains the optimal distance between them. (We discuss the dynamics within the synapse later.) This serves to isolate the synapse from the space around the neuron, and so limits the dispersion of transmitter substances released by the axon terminal into the extracellular space. Children are not just small adults Now you can understand why children are not just small adults. Children’s brain connections are different than adults, and so children necessarily process the world in a different way than their parents. Figure 3.4 below shows brain images (heads are facing to the left) when children and adults were given the same task — a “noun/verb” task. They heard a noun, such as car, and generated a verb. What verb might you generate for the word car? Drive. For the word bike? Ride. For the word food? Eat. Notice, children perform this task by primarily using the back of the brain (right of the figure). This is the visual association area, the area that creates concrete perception. When adults did this task, the most active parts of the brain were in the front (right of the figure).”
― Frederick Travis Ph.D., Your Brain Is a River, Not a Rock

“Here’s a research study that shows just how differently teens’ brains function: In a Magnetic Resonance Imaging (MRI) study, teenagers and adults were presented pictures of people who looked scared or anxious. The adults recognized the fear in the faces but placed the experiences in a larger context, so it didn’t affect them personally. The opposite was true of the teens: they did not report that the faces were fearful, but they became emotionally involved and reported more fear and anxiety themselves. In teens, the parts of the brain that process gut reactions and primitive emotions — the amygdala and insula — were active. But in adults, the frontal lobes were activated as well. In other words, the teenagers’ brains responded emotionally. They felt upset but their brains did not identify the source of those feelings. The adults’ brains added reason to that response. Remember this when your teen gets upset “for no reason.” He may not be able to say why he’s feeling that way, but his feelings are still valid. He doesn’t have the connections between his rational brain and his emotional brain that would allow him to explain it. Logic doesn’t help because the teen’s brain cannot follow abstract logic. They are doing the best they can with the brain connections they have. This is especially true if your teen is a boy. As we see later, girls have more connections between their emotional and executive centers. Astrocytes: Functional and structural support Astrocytes are another class of glial cells. They are star-shaped, hence their name, and provide structural and functional support for the neuron. Astrocytes form the matrix that keeps neurons in place. But they are more than inert bricks in a passive wall. Rather, they function more like the mother who ensures her children have brushed their teeth, are wearing their coats in winter, and are eating good meals. An astrocyte is pictured in Figure 3.3. Astrocytes sit between blood vessels and neurons and breakdown glucose from the capillaries into lactic acid, which the mitochondria of the neurons use for energy. As a wise mother, they do not break down all of the glycogen they receive from the blood, but create a reserve for times when the metabolic need of neurons are especially high.”
― Frederick Travis Ph.D., Your Brain Is a River, Not a Rock

“The corpus callosum, which connects the left and right hemispheres of the cortex, myelinates from 7 to 10 years of age. At age 10, a child’s thinking speeds up noticeably. Ask seven-year-olds a question and it will take a long time for them to respond. Sometimes you can almost see the question move up to the brain and the answer go slowly back down to the mouth. This really became clear to me at our dining table. Our family knows seven different graces to say before meals, and each of our three daughters wanted to choose grace. So we suggested that each daughter could choose grace before breakfast, before lunch, or before dinner. Our youngest daughter, then age six, chose grace before lunch. Lunch is the shortest meal time — we have to walk home, eat, clean up, and walk back to school. Every lunch when we asked her what grace we should say, she would be absolutely quiet for a very long time. She would look around the room, furl her brows, obviously thinking hard, and then announce which grace to say — and it was always the same one. I got a little angry. Was this a power trip? Was she trying to control us? After all, we couldn’t eat until she chose a grace. I finally realized that, because her corpus callosum connecting her left and the right hemispheres was not fully myelinated, the signal was going very slowly back and forth in considering which of the seven graces to say. She was thinking as fast as her brain would allow. The teenage brain The last connections to mature are those between the front and the back of the brain; these connections begin to myelinate at age 12 and continue through age 25. The back of the brain is the concrete present. Environmental stimuli from the senses activate the back of the brain, where a picture of the world is created, like a movie on a screen. This picture is then sent to the front of the brain, the executive centers — the “CEO” or boss of the brain. The frontal lobes place the concrete present — what is happening right now — in the larger context of past and future, plans, goals, and values. Even though teenagers may look like adults, their brains are still maturing. The teen’s brain, whose frontal connections are not fully myelinated, is like a company whose CEO is on vacation. Each department is moving full speed ahead without the benefit of knowing the big picture. Teens are very passionate; they are engulfed by their ideas. They can generate a plan that takes into account their immediate circumstances, but they don’t see the bigger picture.”
― Frederick Travis Ph.D., Your Brain Is a River, Not a Rock

“Rate of myelination in different brain areas The various brain areas begin and end myelination at different ages. For example, visual areas finish myelinating by six months. At that age an infant can see an object moving through space as a homogeneous object; before that, it’s just a collection of disconnected colors and edges. Watch babies wave a toy back and forth in front of their eyes. This rehearsal wires up the visual areas so they can begin to recognize and track objects. Over and over, the same groups of neurons fire together, forming visual functional groups that eventually work together well enough to let the baby recognize familiar objects. Babies’ other senses work along with sight to help form a mental image of objects. Here’s one study that continues to astonish me every time I think about it: Newborns, still in the hospital, were given pacifiers to suck. There were several different shapes: square, round, pointed. Large models of all the different-shaped pacifiers were hung above their cribs. The babies stared longest at the pacifier that matched the one that had been in their mouth. These infants appeared able to relate the mental image created with touch — what was in their mouths — with the one created with vision — what was dangling above their heads. I remember the first time our oldest daughter saw a book. She was about three months old — barely able to sit up — and we put a cardboard book with very simple pictures of toys in front of her. Instantly she put her face right above the book, and she inspected every square inch of the page from about an inch away. Then she sat back up and slapped the pages all over. We could almost see her brain working: “What is this? It’s flat but it reminds me a lot of the things I see around me.” She combined the senses of touch and sight together to examine a new phenomenon in her world. Speech begins with babbling at around six months of age. I remember our youngest daughter beginning speech by mimicking the up and down flow of the sentence before she began to make individual sounds. The flow of speech is supported by language centers in the right hemisphere; the details of speech are supported by language centers in the left hemisphere. Our daughter was practicing how to talk, using the brain areas that were currently available. Her right hemisphere appeared to mature before her left hemisphere. As the speech areas develop and these groups become more extensively coordinated, the child’s speech becomes clearer and connected. The auditory areas finish myelinating by two years. The child now has the brain foundation for speech production. She can distinguish the individual sounds that make up words, and can begin to string words together into phrases and sentences. The motor system is myelinated by four years. Before that, children are very slow to respond. Have you ever played catch with a three-year-old? He holds out his arms, the ball hits his chest, it falls on the ground — and then he closes his arms. It takes so long for the message to move from his eyes to his brain, from his brain to the spinal cord, and finally from his spinal cord to his arms, that he misses the ball. You can practice with him all you like, but his reactions won’t speed up until his motor system myelinates.”
― Frederick Travis Ph.D., Your Brain Is a River, Not a Rock

“Figure 2.2 Number of connections over 25 years across brain areas. This process — neural exuberance followed by pruning of connections — makes the human brain highly adaptable to any environment. Is the infant born in an urban or an agricultural society? Is it the year 2012 or 1012? It doesn’t really matter. The brain of a child born in New York City or in Nome, Alaska, is similar at birth. During the next two decades of life, the process of neural exuberance followed by pruning sculpts a brain that can meet the demands, and thrive in its environment. Brain differences at the “tails” of the distribution As with any natural process there is a range of functioning, with most individuals in the middle and a small percentage of individuals being far above and far below the mean. While the general pattern of increasing and decreasing brain connections is seen in all children, important differences are reported in children whose abilities are above or below those of the average population. To investigate children above the normal range, Shaw used Magnetic Resonance Imaging (MRI) to follow brain structure in 307 children over 17 years. Children with average IQs reached a peak of cortical thickness (and therefore number of neural connections) around age 10, and then pruning began and continued to age 18. Children with above-average IQs had a different pattern: a brief pruning period around age 7 followed by increasing connections again to age 13. Then pruning ensued more vigorously and finished around age 18. There were also differences in brain structure. At age 18, those with above-average IQs had higher levels of neural connections in the frontal areas, which are responsible for short-term memory, attention, sense of self, planning, and decision-making — the higher brain functions. At the other end of the spectrum, individuals diagnosed with schizophrenia, compared to normal children, lose 3% more connections each year from age 10 to 18. Symptoms of schizophrenia emerge in the late teens, when the cortical layer becomes too thin to support coherent functioning. A thinner cortical layer as a young adult — about 20% less than the average — could account for the fragmented mental world of people diagnosed with schizophrenia. Who is in control? Neural exuberance — increasing and decreasing connections — is genetically controlled, but the child’s experiences affect which connections are pruned and which remain. Circuits that a child uses are strengthened. So a youngster who learns to play the piano or to speak Italian is setting up brain circuits that support those activities — she will find it easier to learn another instrument or language. ​Warning to parents: This doesn’t mean you should inundate your toddler with Italian, violin, martial arts, and tennis lessons. Young children learn best when following their natural tendencies and curiosity. Children learn through play. Undue stress and pressure inhibits the brain’s natural ability to learn.”
― Frederick Travis Ph.D., Your Brain Is a River, Not a Rock

“Figure 2.1 Cortical connections over two years adapted from Conel The top row shows the baby’s cortex at birth, then at one month and at three months. They all look about the same, don’t they? But look what happens at six months (bottom left box): the number of cell bodies remains the same, but the number of connections has multiplied exponentially. The connections grow so quickly in the first three years of life that neuroscientists call it neural exuberance. Neural exuberance! The name is well earned: The baby’s brain makes 24 million new connections every minute, and this continues for the first three years of life. Each neuron may be connected to 1,000 other neurons — that multiplies out to 100 trillion possible connections between neurons, more than the number of stars in the universe. This high level of connectivity between brain cells leads to the cortex of a three-year-old being twice as thick as an adult’s! As connections are created, new abilities emerge. For example, when connections grow in Broca’s area — speech production — around six months, then children begin to speak. Around nine months of age, the frontal areas (behind the forehead) become more interconnected, and that’s when most children develop object permanence: knowing that objects continue to exist even when they are out of sight. Before object permanence develops, when Mom is out of sight she’s no longer in the baby’s universe. This is why young babies are inconsolable when Mom leaves. Once they start to develop object permanence, babies can hold on to an internal image of Mom. This is about the age that babies play peek-a-boo. Mom disappears when she puts the blanket over her head, but the nine-month-old knows Mom’s still there even if he can’t see her. The infant tests his “knowledge” when he pulls the blanket off and sees — sure enough! —Mom really is there! What is the use of so many brain connections in the first three years of life? These connections are ready-made highways for information to travel along. The toddlers’ ability to quickly adapt and learn is possible because they have a vast number of brain connections available for making sense of the world. Thanks to neural exuberance, the child does not need to create connections on the spur of the moment to make meaning of each new experience; myriad connections are already there. Pruning of connections The number of connections remains high from age 3 until age 10, when the process of neural pruning begins. Connections that are being used remain; others get absorbed back into the neuron. It’s similar to pruning a bush. After pruning, individual branches get thicker, fruit is more abundant, and the whole bush gets fuller. This seems a little counter-intuitive, but pruning works because it allows the plant’s limited resources to go to its strongest parts; water and nutrients are no longer wasted on spindly branches and dried-out roots. Similarly, when unused brain connections are pruned, neural resources are more available for brain areas that are being used. This results in a more useful and efficient brain that’s tailor-made to meet each individual’s needs. This process of pruning occurs in all brain areas. Figure 2.2 presents findings published by Sowell and associates. They measured Magnetic Resonance Imaging in 176 normal subjects from age 7 to 87 years. The x-axes in these graphs present years from 10 to 90 years. Notice there is a common pattern of decreasing connections in all brain areas. In some brain areas this change is steeper, such as in frontal areas, but is flatter in other areas such as temporal areas in the left hemisphere.”
― Frederick Travis Ph.D., Your Brain Is a River, Not a Rock

“Unassembled at Birth Children are not born with fully connected brains ready to process the world. They are born with their brains unassembled. Imagine buying a computer, opening the box, and finding only a bag of parts. This is analogous to the child’s brain at birth: at birth newborns have 100 billion brain cells — the brain cells they will have for their entire life. But these cells are not connected. Newborns do not see Mom, Dad, sister, or brother. For them, it’s not an integrated picture: head, neck, shoulders. They don’t hear smooth, sequential sounds. The baby’s senses are assaulted by disconnected, constantly changing lights and sounds. The brain circuits needed to process experience are simply not there yet. Natural increase in number of connections Luckily, the newborn’s brain knows exactly what to do; it’s in the DNA. The brain begins a well-orchestrated process of first increasing the number of connections between brain cells or neurons, and then after 5 to 6 years eliminating the ones not used and keeping those that were used. Take a look at Figure 2.1, which shows magnified sections of the surface of the brain, the cortex. The cortex integrates all our sensations into conscious experiences. This is a hand drawing from a Golgi stain of the cortex from Conel. In reality, the cortex is the thickness of a nickel. This particular figure shows the connections in Broca’s area, just above and behind the temples, where speech is produced. Each triangle represents a cell body, which controls and directs the activity of the neuron; the lines are dendrites (input fibers) and axons (output fibers) that connect the neurons.”
― Frederick Travis Ph.D., Your Brain Is a River, Not a Rock

“The low road is our “gut reaction,” our reflexive response to an experience. It’s fast because there’s no processing involved, just instinct. The high road is our thoughtful response to experience. It’s slower because it involves the sensory and association cortex, which uses multiple self-reference pathways to consider how the current experience relates with past experiences, current ideas, and future plans.”
― Frederick Travis Ph.D., Your Brain Is a River, Not a Rock