The Brain: Our Sense of Self

“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 skillfully 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.

Scientists have worked for many years to unravel the complex workings of the brain. Their research efforts have greatly improved our understanding of brain function. During the past decade alone, scientific and technical progress in all fields of brain research has been astonishing. Using new imaging techniques, scientists can visualize the human brain in action. Images produced by these techniques have defined brain regions responsible for attention, memory, and emotion. A series of discoveries (in multiple fields of study) has displaced the long-standing assumption that brain cells are stable and unchanging. Amazingly, new findings show that some adult brain cells can divide and grow! In addition, advances in research are allowing scientists to analyze and make progress toward understanding the causes of inherited brain disorders such as Alzheimer’s disease and Parkinson’s disease. Taken together, these discoveries provide hope for the recovery of nervous system function lost through injury or disease.

Despite these and other significant advances in the field of brain research, most of the processes responsible for the integrated functioning of billions of brain cells remain a mystery. Research on the brain in the new millennium is crucial to our effort to come to a complete understanding of this fascinating organ. In turn, improved understanding makes the development of new treatment options possible. Research continues to bring new insights into how the brain is put together, how it works, and whether damage to the brain can be reversed.

An essential aspect of any scientific research is communicating results to the public in a way that is easily understood. The American public has the opportunity to learn of new research findings about the brain regularly through media reports of scientific breakthroughs and discoveries. However, not all the information we receive is accurate. Commercial products promoted through television advertisements claim to improve memory, enhance concentration, or relieve depression, among other things. The media may oversimplify research findings into a “sound clip” open to misinterpretation. In addition, movies, television shows, and the World Wide Web often contain inaccuracies in their portrayal of research findings about brain structure or function.

To correctly interpret the information transmitted through these venues, we need a better understanding of basic concepts related to the brain. By providing students with a conceptual framework about the brain, we significantly increase our chances of producing an informed public that has the tools to interpret brain research findings. Accordingly, it is the goal of this supplement to provide teachers and students with correct information regarding the brain, its role in the nervous system, and how it provides us with our sense of self.