Myths and realities about the brain


This article is taken from, The Brain: Our Sense of Self, by US The National Institutes of Health And National Institute of Neurological Disorder and Stroke.

“I think, therefore I am.” —René Descartes, 17th-century philosopher

Few of us question the crucial importance of the brain. It is vital to our existence. Our brains enable us to think, as René Descartes so skilfully pointed out nearly 400 years ago. Yet the human brain is responsible for so much more. It directs almost everything we do. It controls our voluntary movements, and it regulates involuntary activities such as breathing and heartbeat. The brain serves as the seat of human consciousness: it stores our memories, allows us to feel emotions, and gives us our personalities.

The brain makes up only 2 percent of our body weight, but it consumes 20 percent of the oxygen we breathe and 20 percent of the energy we consume. This enormous consumption of oxygen and energy fuels many thousands of chemical reactions in the brain every second. These chemical reactions underlie the actions and behaviors we use to respond to our environment. In short, the brain dictates the behaviors that allow us to survive.

As a result of the misinformation presented by various media, many people maintain misconceptions about the brain and brain function. The problem may be compounded by textbooks for middle school students that present little, if any, scientific information on the brain as the organ that controls human behaviour. As a result, students may build their understanding of the brain on “fictions” rather than facts. The constructivist learning model holds that when students dispel their own misconceptions, they are more open to constructing a correct understanding of the subject. The following list of commonly held misconceptions about the brain, followed by correct information about each concept, should help teachers address these issues in their classrooms.

Myth: The brain is separate from the nervous system.

Reality: Students often assume that the brain and the nervous system are separate, unrelated entities. Furthermore, surveys of middle school students have shown that they often believe organs such as the heart and lungs are part of the nervous system. In reality, the nervous system is composed of only the brain, the spinal cord, neurons, and neural support cells.

Myth: The brain is a uniform mass of tissue.

Reality: The only exposure that middle school students often have to brain anatomy is a photo or drawing of a gray, bulbous, wrinkled mass of tissue. This may lead students to believe that the brain is uniform throughout. Although the brain may appear uniform at a gross anatomic level, it is actually composed of billions of specialized cells. These cells, called neurons and glia, are further organized into specialized functional regions within the brain. This type of variation within the brain is what allows it to function as “command central” of the human body.

Myth: Control of voluntary activity is the sole purpose of the brain.

Reality: When do we use our brains? Students may have the misconception that they use their brains only when they are doing something, such as thinking or performing a physical action. Most students do not recognize that we use our brains constantly for a variety of activities that, while crucial to our survival, require no conscious thought. For instance, the human brain is responsible for involuntary activities, such as regulating heartbeat, breathing, and blinking. Although the brain controls both voluntary and involuntary activities, different regions of the brain are devoted to each type of task.

Myth: The vertebral column and the spinal cord are the same thing.

Reality: The only exposure most students have to the human spine is as a component in models of skeletons. Thus students may assume that the spine consists solely of the skeletal structure of the vertebral column, or backbone. They can feel their own backbone, and they know that it is a structural component of their body. Students may not realize that the backbone encases the spinal cord, a vital part of our nervous system.

Myth: The brain does not change.

Reality: The idea that the brain does not change after growth ceases may be the greatest misconception that students have. In actuality, the brain changes throughout life. During embryonic development and early life, the brain changes dramatically. Neurons form many new connections, and some neurons die. However, scientists have discovered that changes in the brain are not restricted to early life. Even in the adult brain, neurons continue to form new connections, strengthen existing connections, or eliminate connections as we continue to learn. Recent studies have shown that some neurons in the adult brain retain the ability to divide. Finally, damaged neurons have some capability to regenerate if the conditions are right.

Myth: Learning disabilities are the only manifestation of a problem with brain function.

Reality: Many students will encounter someone who has a learning disability during their school years. For many students, this is their only experience with a brain disorder. Because many types of neurological diseases (such as Alzheimer’s disease and Parkinson’s disease) affect older people, students may not have experience with them. They may not realize that emotional and behavioral conditions such as depression and hyperactivity are also brain disorders. Students should be aware that diseases of, and injuries to, the brain and nervous system afflict millions of Americans of all ages each year. Although some injuries and diseases are of short duration, others are permanent and disabling.

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