The Society of Neuroscience is a larger association of professional scientists in all of experimental biology, and also the fastest growing. Far from being very specialized, the field is as broad as the natural sciences, with the nervous system serving as a common point. Understanding how the brain works requires knowledge about many things, from the structure of the water molecule to the electrical and chemical properties of the brain, and why Pavlov's dog salivated when a buzzer rang. This chapter intends to provide a quick overview of Neuroscience and its evolution. The main source of this chapter was (Bear, Barry, & Paradiso, 2002).
TopThe History Of Neuroscience
You probably already know that the nervous system - the brain, the spinal cord and the nerves of the body - are fundamental to life and allow you to feel, move, and think. How did this idea come about?
There is evidence to suggest that even our prehistoric ancestors understood that the encephalon was essential to life. Prehistoric records are rich in examples of hominid skulls, dating back millions of years, showing signs of lethal cranial lesions, presumably inflicted by other hominids. About 7,000 years ago, people were already making holes in the skulls of others (a process called trepanation), evidently with a view to healing rather than malingering. The skulls show signs of healing after the operation, indicating that this procedure was performed on living subjects, and not merely a ritual conducted after death. Some individuals survived multiple cranial surgeries. We are not very clear about what these primitive surgeons wanted to do, although there are those who speculate that such a procedure could have been used to treat headaches or mental disorders, perhaps offering the “evil spirits” a way out.
Writings recovered from doctors in ancient Egypt, dating back almost 5,000 years, indicate that they were already aware of many of the symptoms of brain damage. However, it is also clear that for them it was the heart, not the brain, the seat of the spirit and the repository of memories. Indeed, while the rest of the body was carefully preserved for life after death, the dead man's brain was removed by the nostrils and thrown away! The view that the heart was the seat of consciousness and thought remained until the time of Hippocrates.
The Brain as Seen in Ancient Greece
Consider the notion that the different parts of your body are different because they serve different purposes. The structure of the feet and hands are very distinct, and they perform very different functions: we walk with our feet and manipulate objects with our hands. Thus, we can say that there is a clear correlation between structure and function. Differences in appearance predict differences in function.
What can we predict about function by looking at the structure of the head? A quick inspection and few experiments (like closing your eyes) reveal that the head specializes in noticing the environment. In his head are his eyes and ears, his nose and his tongue. Even gross dissections show that the nerves of these organs can be traced through the skull into the brain. What can you conclude from the brain from this observation?
If your answer is that the brain is the organ of sensations, then you came to the conclusion of many Greek scholars of the fourth century BC. The most influential scholar was Hypocrites (469-379 BC), the father of Western medicine, who said he believed the encephalon was not only involved in sensations, but it was also the seat of intelligence.
However, this view was not universally accepted. The famous Greek philosopher Aristotle (384-322 bc) clung to the belief that the heart was the center of the intellect. What function did Aristotle reserve for the encephalon? He proposed that it was a radiator to cool the blood that was overheated by the heart. The rational temperament of humans was then explained by the great cooling capacity of the encephalon.