Meet Your Brain | BioEd Online
Meet Your Brain. billion braincells make you the person you are. Here's a beginner's guide to how they do it. You've heard for much of your life that the human brain is amazing. It's true. That soft, squishy blob between your ears—the blob that runs your life—is pretty. Meet your brain: a short introduction to neuroscience. Psychology and science. Discover how 4 brainstructures control our emotions and decisions. ().
Humans have large brains relative to body weight. The adult human brain weighs about three pounds 1,—1, grams.
But would a bigger brain make you smarter? A sperm whale's brain weighs about 17 pounds, or 7, grams.
The brain's various parts and its nerve cells are connected by nearly 1 million miles of nerve fibers. The human brain has the largest area of uncommitted cortex with no specific function identified so far of any species on earth.
This gives humans extraordinary flexibility for learning. Scientists divide brain areas into lobes see Figure 1. The occipital lobe is in the middle-back area of the brain, and it's primarily responsible for vision.
The temporal lobes are located above and around the ears on the left and right sides of the brain. These areas are primarily responsible for hearing, memory, and language. That's part of the essence of reading: The frontal lobeis the area around your forehead. It's involved with purposeful activities like judgment, creativity, problem solving, and planning. It also holds short-term memory so you can juggle two or more thoughts at once.
The parietal lobe is at the top and back areas of your head. Its duties include processing higher sensory and language functions. Main Areas of the Human Brain The territory in the middle of the brain includes the hippocampus, thalamus, hypothalamus, cingulate, basal ganglia, fornix, striatum, and amygdala see Figure 1. You could call this area both the chemistry lab and the drama department of the brain. Sometimes known as the limbic system, it represents 20 percent of the brain by volume and is partly responsible for emotions, sleep, attention, body regulation, hormones, sexuality, sense of smell, and production of many brain chemicals.
In either case, this middle area of the brain, along with the parts of the cortex, helps you feel what you feel about the world. It may be dispersed throughout the cortex, or it may be in the thalamus, or it may be located near the reticular formation, a structure atop the brain stem Crick, You'd think that this part of the brain would be easy to find—just cut away brain areas until a person loses awareness, right?
But it's not just a simple case of Jack the Ripper meets the Nutty Professor. Remember, the second essential feature of the brain is integration, or strong connectivity. That means many areas connect to and influence other portions, so that specific sections of the brain may contribute separately and collectively to your sense of self. In short, one critical quality that makes the brain work so well is its degree of connectivity, not its individual structures.
The Constantly Changing Brain Not long ago, the prevailing view of the brain was that it remained fairly constant throughout a person's life. We knew that the brain was smaller in childhood; once it reached maturity, we thought it remained more or less stable over many years before beginning to deteriorate somewhat with age.
Yes, the most amazing new discovery about the brain might be that human beings have the capacity and the choice to be able to change our own brains. This finding suggests that your experiences and the actions you take can lead to changes in your brain. These changes, in turn, change you. We also know that your life influences your genes at the same time that your genes regulate your life. In short, we can and do influence our own genetic material; this is a profound revelation!
The result of the various interrelation of humans shaping environments and environments shaping humans is that there is no fixed human brain; it is always a work in progress. Another way to put it is that your brain is dynamic and constantly changing as a result of the world you live in and the life you lead. Whether you are 2 or 92, your brain is a cauldron of changing chemicals, electrical activity, cell growth, cell death, connectivity, and change.
This dynamism makes it very challenging to get clear data on what's happening in the brain. From birth to the teenage years, the brain undergoes a fourfold increase in volume Johnson, Infants are born with roughly a trillion connections synapses already in place. The infant's interaction with his or her environment helps create many additional connections within the cortex. Throughout life, your brain is losing connections at the same time it is creating new connections.
It's a bit like going out shopping for new clothes at the same time that someone is raiding your closet back at home. This ongoing refinement results in a highly adapted, highly specialized brain see Figure 1. Longtime neuroscience dogma held that the mammalian brain couldn't grow new brain cells, and mainstream science was absolutely certain that new brain cell growth neurogenesis was impossible in the human brain.
However, the ground-breaking research of Kempermann, Kuhn, and Gage showed not only that humans do grow new neurons, but also that these new cells survive and become functional and integrated.
Just as important, a follow-up study Van Praag et al. In fact, researchers have identified more than 15 factors that either enhance or impair neurogenesis. Again, the complexity of the brain comes into play. Although factors such as excess stress can inhibit growth, exercise can encourage it, as we'll see in later chapters. All of this paints a complex picture of what exactly you have in your brain at any particular moment. Inside your brain, cells are being eliminated at the same time new cells are being born.
You lose some brain cells every day through attrition, decay, and disuse, and we know that certain behaviors affect the loss of brain cells. Scientists differ on what your daily net gain or loss in brain cells might be. But even if you lose a half-million neurons per day, it would take centuries to literally lose your mind. Some of the most interesting recent research on the brain's adaptability shows how activities can influence the actual mass and organization of the brain.
We'll just use this nearby spot. These studies and others provide evidence that many years of specific fine-motor exercise prompts brain reorganization and nerve growth. What's truly amazing is that this constant reorganization of the brain is always purposeful—driven not by a mysterious signal but by real-life use and disuse. The brain has no single command center; it's a system of systems governed by life experience and by complex processes, which appear to be both variable and fixed, random and precise.
Your constantly changing brain is shifting your moods, your thinking, and your actions through countless electrical and chemical changes. Each of these changes results in a shifting state of mind.
In summary, the brain is a dynamic, opportunistic, pattern-forming, self-organized system of systems. So why is this new view of the brain so important to you, as a teacher?
Because it reinforces that every student in your classroom has the capacity for change. Yes, genetics plays a part in who students are and how they behave and reason, but each of them can change. Even your most frustrating student can improve. Now that should be the best news you've gotten all day. Brain areas and structures can communicate via glial cells too. And certainly the bloodstream creates a common network, circulating brain chemicals known as neurotransmitters e.
It's fair to say that very little happens in one part of the brain without some kind of potential effect in other areas. It's just a matter of degree. The two sides of the brain, the left and right cerebral hemispheres, are connected by bundles of nerve fibers. The corpus callosum see Figure 1. In healthy brains, this interhemispheric highway allows each side of the brain to exchange information freely.
Patients whose corpus callosum has been severed can still function in society, but suffer an inability to integrate certain brain functions. For example, a subject who is shown an apple in his right field of vision might know what it is, but not be able to come up with the correct name for it. In general, the left hemisphere tends to process information in parts, in a sequence, and using language and text representations.
But none of these tendencies guarantees that the left brain will be logical. If a learner sequences words and then assembles the parts of sentences, there's no guarantee that the written material is logical.
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Any high school English teacher will confirm this. The use of logic is not a given; it's a learned, highly complex, contextually based, and rule-generated subskill that probably uses many brain areas. Again speaking generally, the right hemisphere tends to process information as a whole, in random order, and within a spatial context.
But, like the left-brain tendencies, none of these tendencies guarantees that the right brain will be creative.
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Creativity can be either more right- or more left-hemisphere dominant. Logic can be either more left- or more right-hemisphere dominant. Clearly, some people do prefer linear processing and others do prefer randomness.
But that's all it is—a preference. Many of the greatest scientific and mathematical discoveries of the last years fit the qualities of both right-hemisphere processing random, focused on the whole, having a spatial context and left-hemisphere processing sequential, focused on the parts, relying on language. Recent discoveries in cognitive neuroscience have shown many nuances in the left- and right-brain preferences.
Trained musicians process music more in their left hemisphere, while novice musicians process it more in the right hemisphere. The brain of a more-experienced musician is trained to recognize the elemental parts of music more than a beginner's brain.
Among left-handed people, almost half use their right not left hemisphere for language. And here's something odd: But beginning chess players usually have more activity in the left hemisphere. Richard Davidson at the Laboratory for Affective Neuroscience at the University of Wisconsin has shown that the right hemisphere is activated with negative emotions and the left hemisphere is activated with positive emotions.
People with more left-hemisphere activations tend to be happier and more positive than those with a right-hemisphere dominance. We also know that the left hemisphere controls movements on the right side of the body, and vice versa.
As you may have guessed, it would be difficult to have a left- or right-brained school. Although a teacher could structure an activity so that it was hemisphere-dependent, on most typical schooldays, students use both sides of the brain.
Let's put aside the notion of right brain versus left brain and move on. Actually, the brain has a problem to solve. Because humans have so much uncommitted brain tissue at birth proportionally more than any other speciesour brains have an extraordinary opportunity to become customized by life experiences.
The competition concept is simple: How the Brain Learns Although there are many examples we could look to for an illustration of the brain's complexity, it's the learning process that we want to focus on. At the most general level, the brain processes for learning are deceptively simple see Figure 1.
Input to the brain arrives from the five senses or is generated internally through imagination or reflection. A good analogy is to think of the limbic system as the "glue" that connects your thinking brain, or cerebral cortex, to your physical brain, or your reptilian brain.
The limbic system is an integral part to the Birth Into Being Method. Sitting on the very top is your cerebral cortex, or neocortex. This is the newest part of the brain, evolutionary speaking. This is where rational thinking takes place. When new ideas inspire cognitive connections, your cortex physically changes, rewiring itself as your patterns of thought change. Lately, ideas such as neuroplasticity are showing the amazing capability of the brain to change, at any age. It really is possible to teach and old dog new tricks, as they say.
Now that we've delved into the depths of the three parts of the brain, let's look the reptilian, limbic, and cortex as a whole. Below is a handy chart, dreamt up by Elena Tonetti-Vladimirova. You can see on the left side how the parts of the brain correspond to the Body, Soul, and Spirit.
On the right side, the analogy is expanded and enriched.