The Mind and The Brain

The Mind and The Brain | Our own minds as very real to us, and yet the mind does not seem to have a physical existence. That is, it cannot be located in space. What is the relationship between the mind and the body? Dualists (believers in two) believe that both the body and the mind exist. According to dualists, the body is made of matter and exists in time and space, and the mind is not made of matter and exists outside of the time and space. To the dualists, the body is like a machine that’s run according to the laws of physics and chemistry, but the mind is not controlled by these laws. (One philosopher called the mind “the ghost in the machine.”)

Some philosopher called materialistic say that only matter exists and that the mind is an illusion. One humorist summed up both these arguments by saying “No matter, No mind.”

Many philosophers and scientists have tried to decide where the mind is located in human body. Two Greek philosophers, Empedocles and Aristotle, said that it was in the heart. Another Greek, Hippocrates of Cos, said that is was in the brain. An early Doctor, Galen, thought the mind was located in the fluid inside the brain. At the beginning of the nineteenth century, a subject called phrenology was popular. According to Phrenology, different functions of the mind were located in different parts of the brain. Phrenology also believed that the bumps on a person’s head revealed things about the brain (and mind) of that person.

Many modern scientists believe that the mind and the brain are connected, or that possibly the mind is the result of what the brain does Modern scientists who study the nervous system (neurologists) believe also that a thin layer on top the cerebrum (called the cerebral cortex) is responsible for thinking and consciousness. The cerebral cortex is a quarter an inch thick and holds three quarters of the brain’s 50 billion neuron or nerve cells.

Although most of what we regard as thinking goes on in the cerebral cortex. The other parts of the brain have different functions to perform. For example, the limbic system, which is a part of the forebrain, is responsible for emotions and memory. The medulla oblongata and a neighboring organ, the pons, control breathing and heart rhythm. The cerebellum is involved with motor responses (movements).

Even within the cerebrum, different locations seem to be associated with different kind of mental activity. Scientists have been investigating the different functions of the right and left cerebral hemispheres for some time. One way to study these functions is to inject a person with a chemical compound called deoxyglucose, (or DG) that contains radioactive oxygen. This makes it possible to see what areas of the brain are being used at a particular time because the DG concentrates in the areas of the brain that are working then. Therefore, scientist can tell which parts of the brain are being used by measuring the amount or radioactivity in different parts of the brain. As a person goes from doing mental arithmetic to imagining he or she is walking down a street to describing the contents of his or her living room, different parts of the person brain “light up” by becoming more radioactive.

Electric stimulation of the brain can also show that the brain has different areas. When one area of one person’s brain was stimulated. He thought about the death of his father with feeling of sorrow and guilt. When another area of his brain was stimulated, he had happy thoughts about his girl friend.

Although the brain areas appear to be specialized, large sections of the brain can be surgically removed without much permanent damage to the functioning of the mind of the individual. This would seem to show that the brain acts a s a whole in many ways and that one part of the brain can take over the functioning of another part.