Unlocking The Brain
The brain is a difficult organ to study. It is locked up inside a bony skull and protected by several layers of membrane and cushioning fluid.Our knowledge of the brain -- what it does, what it is capable of, and which areas are responsible for each function - increases only as quickly as researches can figure out new methods for studying this mysterious part of ourselves. In the last few decades, however, scientists have developed and perfected a number of methods that are beginning to unlock some of the secrets of our brains.
Electrical Stimulation of The Brain (ESB). Because the transmission of impulses through the nervous system is electric in nature, researchers can use electricity to stimulate the functioning of particular areas of the brain. They place electrodes in the area of the brain they wish to study and pass an electric current through the electrode. The current stimulates that area of the brain in the same way an impulse from another neuron would. The researchers can stimulate brain regions and observer how the behavior of their subjects changes.
Electrical Recording. Just as researchers can stimulate the brain with electric current to map out its functions, they can record the electrical activity produced by different areas of the brain. The electric potentials of neuronal activity are amplified and converted by a machine into written records which appear as lines on a graph. The researchers may, for example, present a visual stimulus to a subject hooked up to a machine and record how part of his brain reacts while processing this new information. Brain researchers have developed such precise recording methods that they can record the activity of one neuron. With larger electrodes implanted in the brain, they can record the summed activity of many neurons to pinpoint the functions of specific areas in the brain. They can also study patterns of brain activity produced in several regions of the brain by placing electrodes on the surface of the skull and recording them on the electroencephalograph (EEG).
Electrical Stimulation of The Brain (ESB). Because the transmission of impulses through the nervous system is electric in nature, researchers can use electricity to stimulate the functioning of particular areas of the brain. They place electrodes in the area of the brain they wish to study and pass an electric current through the electrode. The current stimulates that area of the brain in the same way an impulse from another neuron would. The researchers can stimulate brain regions and observer how the behavior of their subjects changes.
Electrical Recording. Just as researchers can stimulate the brain with electric current to map out its functions, they can record the electrical activity produced by different areas of the brain. The electric potentials of neuronal activity are amplified and converted by a machine into written records which appear as lines on a graph. The researchers may, for example, present a visual stimulus to a subject hooked up to a machine and record how part of his brain reacts while processing this new information. Brain researchers have developed such precise recording methods that they can record the activity of one neuron. With larger electrodes implanted in the brain, they can record the summed activity of many neurons to pinpoint the functions of specific areas in the brain. They can also study patterns of brain activity produced in several regions of the brain by placing electrodes on the surface of the skull and recording them on the electroencephalograph (EEG).
Chemical Stimulation and Inhibition. Sometimes researchers inject chemicals into certain parts of the brain. The chemicals may be activators or inhibitors. As with ESB, the experimenter apply the chemicals and then observe the behavior of the organism to determine the precise function of the area in the question.
Lesions. Because of accidents or surgery, certain areas of the brain are destroyed, inactivated, or removed. Psychologists study individuals with brain lesions to observe the behavioral changes that result from the loss of functioning of a particular brain region.
Split-brain Surgery.One type of surgery that has yielded a great deal of information about the brain is the severing of the corpus callosum, the nervous tissue which connects the left and right hemispheres of the brain. Individuals who have split brains appear quite normal but share a few peculiarities which demonstrate the specialized functions of each hemisphere of the brain.
(Source : McNeil, E. B. The Psychology of Human Being. New York: Canfield Press, 1974.)
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