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From the ancient Egyptian mummifications to 18th century scientific research on "globules" and neurons, there is evidence of neuroscience practice throughout the early periods of history. The early civilizations lacked adequate means to obtain knowledge about the human brain. Their assumptions about the inner workings of the mind, therefore, were not accurate. Early views on the function of the brain regarded it to be a form of "cranial stuffing" of sorts. In ancient Egypt, from the late Middle Kingdom onwards, in preparation for mummification, the brain was regularly removed, for it was the heart that was assumed to be the seat of intelligence. According to Herodotus, during the first step of mummification: "The most perfect practice is to extract as much of the brain as possible with an iron hook, and what the hook cannot reach is mixed with drugs." Over the next five thousand years, this view came to be reversed; the brain is now known to be the seat of intelligence, although colloquial variations of the former remain as in "memorizing something by heart". == Early views == The Edwin Smith Surgical Papyrus, written in the 17th century BC, contains the earliest recorded reference to the brain. The hieroglyph for brain, occurring eight times in this papyrus, describes the symptoms, diagnosis, and prognosis of two patients, wounded in the head, who had compound fractures of the skull. The assessments of the author (a battlefield surgeon) of the papyrus allude to ancient Egyptians having a vague recognition of the effects of head trauma. While the symptoms are well written and detailed, the absence of a medical precedent is apparent. The author of the passage notes "the pulsations of the exposed brain" and compared the surface of the brain to the rippling surface of copper slag (which indeed has a gyral-sulcal pattern). The laterality of injury was related to the laterality of symptom, and both aphasia ("he speaks not to thee") and seizures ("he shutters exceedingly") after head injury were described. Observations by ancient civilizations of the human brain suggest only a relative understanding of the basic mechanics and the importance of cranial security. Furthermore, considering the general consensus of medical practice pertaining to human anatomy was based on myths and superstition, the thoughts of the battlefield surgeon appear to be empirical and based on logical deduction and simple observation. During the second half of the first millennium BC, the Ancient Greeks developed differing views on the function of the brain. However, due to the fact that Hippocratic doctors did not practice dissection, because the human body was considered sacred, Greek views of brain function were generally uninformed by anatomical study. It is said that it was the Pythagorean Alcmaeon of Croton (6th and 5th centuries BC) who first considered the brain to be the place where the mind was located. According to ancient authorities, "he believed the seat of sensations is in the brain. This contains the governing faculty. All the senses are connected in some way with the brain; consequently they are incapable of action if the brain is disturbed...the power of the brain to synthesize sensations makes it also the seat of thought: The storing up of perceptions gives memory and belief and when these are stabilized you get knowledge."〔 In the 4th century BC Hippocrates, believed the brain to be the seat of intelligence (based, among others before him, on Alcmaeon's work). During the 4th century BC Aristotle thought that, while the heart was the seat of intelligence, the brain was a cooling mechanism for the blood. He reasoned that humans are more rational than the beasts because, among other reasons, they have a larger brain to cool their hot-bloodedness. In contrast to Greek thought regarding the sanctity of the human body, the Egyptians had been embalming their dead for centuries, and went about the systematic study of the human body. During the Hellenistic period, Herophilus of Chalcedon (c.335/330–280/250 BC) and Erasistratus of Ceos (c. 300–240 BC) made fundamental contributions not only to brain and nervous systems' anatomy and physiology, but to many other fields of the bio-sciences. Herophilus not only distinguished the cerebrum and the cerebellum, but provided the first clear description of the ventricles. Erasistratus used practical application by experimenting on the living brain. Their works are now mostly lost, and we know about their achievements due mostly to secondary sources. Some of their discoveries had to be re-discovered a millennium after their death.〔 During the Roman Empire, the Greek anatomist Galen dissected the brains of sheep, monkeys, dogs, swine, among other non-human mammals. He concluded that, as the cerebellum was denser than the brain, it must control the muscles, while as the cerebrum was soft, it must be where the senses were processed. Galen further theorized that the brain functioned by movement of animal spirits through the ventricles. "Further, his studies of the cranial nerves and spinal cord were outstanding. He noted that specific spinal nerves controlled specific muscles, and had the idea of the reciprocal action of muscles. For the next advance in understanding spinal function we must await Bell and Magendie in the 19th Century."〔〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「history of neuroscience」の詳細全文を読む スポンサード リンク
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