The Human Brain

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The human being is considered to be the ultimate form of life on the earth. This is not because the human body is strong and agile. Many other animals posses skills much superior to humans and are able to perform feats humans can only dream of. The one thing that distinguishes humans from all of the other organisms on this planet is the brain. The brain is the site that controls the human body. However, unlike in animals, in man, the brain is also the site of the mind. The mind gives humans superiority over other creatures. It provides humans with the ability to reason, to feel and to adapt. Because of this, man has achieved so much, and has also realized that much more is still ahead.

During the course of evolution, ever since early Homo sapiens and his ancestors walked on the surface of the earth, man has wondered about himself, and how he relates to the natural world. People learned and adapted to new lifestyles. As time passed, humans learned to record history. They analyzed past events and applied this knowledge to solve problems. These processes improved as more and more people supplied their experiences to the common pool of knowledge. Such co-operation created the modern man with his superb ability to think.

Many sciences were born. Some of them centered around humans. They included, among many others, psychology and neurology. While psychology deals with the mind and human behavior, neurology is the study of the nervous system.

The nervous system of the human being consists of several parts. The main structures are the brain and the spinal chord. The system also includes nerves which sense external and internal stimuli and then relate all information to the central processing unit, i.e. the brain.

Because of man's rapid evolution in technology and medicine, humans now know a great deal more about their own nervous system then they did even a few years ago. This increase in knowledge is partly due to the recent advances in nuclear medicine. Although X-ray machines have been the chief mechanical tools for internal observations of the human body since Wilhelm Roentgen discovered X-rays in 1901, the development of computers made it possible for better and more accurate techniques to be applied to scan the human body. These methods employ various scanners like the CAT, PET, MRI and SPECT.

The CAT is an acronym for Computerized Axial Tomography. This method of scanning generally involves X-rays and enables scientists to view the inside of the head in a three dimensional format on a computer screen. PET stands for Positron Emission Tomography and it is much more complicated than the CAT scan. PET machines bombard the subject with doses of positrons-the anti-matter equivalents of the electrons. As the positrons enter the body, they encounter electrons which are escaping from radioactive elements which have been injected into the bloodstream. When the positrons and the electrons collide, they give off energy which is recorded by a computer. The result is a far more detailed 3-D picture of the brain than the one obtained from the CAT machine. To obtain an even better image, physicians use the MRI, which stands for Magnetic Resonance Spectroscopy. With these three processes combined, every structure of the body can be easily observed. The CAT and the MRI are c ently being used to detect early signs of Multiple Sclerosis in patients who show MS symptoms.

The SPECT equipment is a brand new addition to the family of body scanners. It is still in experimental mode at several United States hospitals, but it has received much positive criticism. The SPECT, which is the short form for Single Photon Emission Computed Tomography, is a device which resembles the PET. However, it uses radiation which is less harmful and the tracers which are injected into the patient are non-radioactive isotopes of Lithium, Carbon and Phosphorus. The system is also much faster which permits quicker diagnoses.

Modern technology is not the only method by which the human nervous system can be studied. Traditional surgical procedures, along with fiber optic cameras and sensors create an image of the brain that is fascinating. It is known that the brain is made up of two hemispheres, left and right, connected by a central "bridge" called the thalamus. In the back of the human skull lies the cerebellum, an organ associated with the control of muscles and maintaining equilibrium.