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History of neuroscience
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".
The earliest reference to the brain occurs in the Edwin Smith Surgical Papyrus, written in the 17th century BC. 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 shudders 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.
In Ancient Greece, interest in the brain began with the work of Alcmaeon, who appeared to have dissected the eye and related the brain to vision. He also suggested that the brain, not the heart, was the organ that ruled the body (what Stoics would call the hegemonikon) and that the senses were dependent on the brain. According to ancient authorities, Alcmaeon believed the power of the brain to synthesize sensations made it also the seat of memories and thought. The author of On the Sacred Disease, part of the Hippocratic corpus, likewise believed the brain to be the seat of intelligence.
The debate regarding the hegemonikon persisted among ancient Greek philosophers and physicians for a very long time. Already in the 4th century BC, Aristotle thought that the heart was the seat of intelligence, while 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. On the opposite end, during the Hellenistic period, Herophilus and Erasistratus of Alexandria engaged in studies that involved dissecting human bodies, providing evidence for the primacy of the brain. They affirmed the distinction between the cerebrum and the cerebellum, and identified the ventricles and the dura mater. 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 physician and philosopher Galen dissected the brains of oxen, Barbary apes, swine, and 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 the movement of animal spirits through the ventricles. He also noted that specific spinal nerves controlled specific muscles, and had the idea of the reciprocal action of muscles. Only in the 19th century, in the work of François Magendie and Charles Bell, would the understanding of spinal function surpass that of Galen.
Islamic medicine in the middle ages was focused on how the mind and body interacted and emphasized a need to understand mental health. Circa 1000, Al-Zahrawi, living in Islamic Iberia, evaluated neurological patients and performed surgical treatments of head injuries, skull fractures, spinal injuries, hydrocephalus, subdural effusions and headache. In Persia, Avicenna (Ibn-Sina) presented detailed knowledge about skull fractures and their surgical treatments. Avicenna is regarded by some as the father of modern medicine. He wrote 40 pieces on medicine with the most notable being the Qanun, a medical encyclopedia that would become a staple at universities for nearly a hundred years. He also explained phenomena such as, insomnia, mania, hallucinations, nightmares, dementia, epilepsy, stroke, paralysis, vertigo, melancholia and tremors. He also described a condition similar to schizophrenia, which he called Junun Mufrit, characterized by agitation, behavioral and sleep disturbances, giving inappropriate answers to questions, and occasional inability to speak. Avicenna also discovered the cerebellar vermis, which he simply called the vermis, and the caudate nucleus. Both terms are still used in neuroanatomy today. He was also the first person to associate mental deficits with deficits in the brain's middle ventricle or frontal lobe. Abulcasis, Averroes, Avenzoar, and Maimonides, active in the Medieval Muslim world, also described a number of medical problems related to the brain.
Between the 13th and 14th centuries, the first anatomy textbooks in Europe, which included a description of the brain, were written by Mondino de Luzzi and Guido da Vigevano.
Work by Andreas Vesalius on human cadavers found problems with the Galenic view of anatomy. Vesalius noted many structural characteristics of both the brain and general nervous system during his dissections. In addition to recording many anatomical features such as the putamen and corpus callosum, Vesalius proposed that the brain was made up of seven pairs of 'brain nerves', each with a specialized function. Other scholars furthered Vesalius' work by adding their own detailed sketches of the human brain.
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History of neuroscience
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".
The earliest reference to the brain occurs in the Edwin Smith Surgical Papyrus, written in the 17th century BC. 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 shudders 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.
In Ancient Greece, interest in the brain began with the work of Alcmaeon, who appeared to have dissected the eye and related the brain to vision. He also suggested that the brain, not the heart, was the organ that ruled the body (what Stoics would call the hegemonikon) and that the senses were dependent on the brain. According to ancient authorities, Alcmaeon believed the power of the brain to synthesize sensations made it also the seat of memories and thought. The author of On the Sacred Disease, part of the Hippocratic corpus, likewise believed the brain to be the seat of intelligence.
The debate regarding the hegemonikon persisted among ancient Greek philosophers and physicians for a very long time. Already in the 4th century BC, Aristotle thought that the heart was the seat of intelligence, while 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. On the opposite end, during the Hellenistic period, Herophilus and Erasistratus of Alexandria engaged in studies that involved dissecting human bodies, providing evidence for the primacy of the brain. They affirmed the distinction between the cerebrum and the cerebellum, and identified the ventricles and the dura mater. 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 physician and philosopher Galen dissected the brains of oxen, Barbary apes, swine, and 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 the movement of animal spirits through the ventricles. He also noted that specific spinal nerves controlled specific muscles, and had the idea of the reciprocal action of muscles. Only in the 19th century, in the work of François Magendie and Charles Bell, would the understanding of spinal function surpass that of Galen.
Islamic medicine in the middle ages was focused on how the mind and body interacted and emphasized a need to understand mental health. Circa 1000, Al-Zahrawi, living in Islamic Iberia, evaluated neurological patients and performed surgical treatments of head injuries, skull fractures, spinal injuries, hydrocephalus, subdural effusions and headache. In Persia, Avicenna (Ibn-Sina) presented detailed knowledge about skull fractures and their surgical treatments. Avicenna is regarded by some as the father of modern medicine. He wrote 40 pieces on medicine with the most notable being the Qanun, a medical encyclopedia that would become a staple at universities for nearly a hundred years. He also explained phenomena such as, insomnia, mania, hallucinations, nightmares, dementia, epilepsy, stroke, paralysis, vertigo, melancholia and tremors. He also described a condition similar to schizophrenia, which he called Junun Mufrit, characterized by agitation, behavioral and sleep disturbances, giving inappropriate answers to questions, and occasional inability to speak. Avicenna also discovered the cerebellar vermis, which he simply called the vermis, and the caudate nucleus. Both terms are still used in neuroanatomy today. He was also the first person to associate mental deficits with deficits in the brain's middle ventricle or frontal lobe. Abulcasis, Averroes, Avenzoar, and Maimonides, active in the Medieval Muslim world, also described a number of medical problems related to the brain.
Between the 13th and 14th centuries, the first anatomy textbooks in Europe, which included a description of the brain, were written by Mondino de Luzzi and Guido da Vigevano.
Work by Andreas Vesalius on human cadavers found problems with the Galenic view of anatomy. Vesalius noted many structural characteristics of both the brain and general nervous system during his dissections. In addition to recording many anatomical features such as the putamen and corpus callosum, Vesalius proposed that the brain was made up of seven pairs of 'brain nerves', each with a specialized function. Other scholars furthered Vesalius' work by adding their own detailed sketches of the human brain.