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4-12-10 The Nervous System -The brain anatomy-color

4-12-10 The Nervous System -The brain anatomy-color -...

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Unformatted text preview: Clicker Question Where are we? Last Last time I talked about… consciousness consciousness and that plants sense and respond appropriately to the environment. the the five senses and how the sense organs perceive and deconstruct the complex environmental signals so that the brain can reconstruct a picture of reality. This This time (and over the next three lectures) I will discuss… In a one-way brain transplant experiment, would you oneyou prefer to be the body that receives the brain or the brain donor? A) Recipient Body B) Brain Donor the anatomy electrical, the anatomy, electrical, cellular and chemical nature of chemical the nervous system that forms a personal version of reality from the sensory input and then triggers our skeletal muscles to contract in order to carry out our will. How How does a knowledge of our anatomy, electrical characteristics, neurons and brain chemicals help us to know ourselves? MindMind-Body Duality I will use the words mind, soul or will mind soul spirit interchangeably spirit interchangeably to indicate our sense of self, our will, who we are, our memories, our feelings, our humanity and our way with words words. Historically Historically the soul has been considered to be immaterial and GodGod-given in nature, yet housed in the body. For example, Plato thought that the soul was an independent and immortal being who was merely housed in the body during its time on Earth. Comfort Comfort Food Foods Foods, which are complex combinations of chemicals not only replenish our body and provide energy but also feed our soul. feed So So maybe it should be of no surprise that the workings of the soul may have a material, physico-chemical physicocomponent. But where in the body is the soul localized? The Seat of the Soul The heart The heart appeared to Aristotle Aristotle (384(384-322 BC) to be the seat of the soul because it was the first visible structure in a developing chick embryo and life ended when the heart stopped beating. The brain The brain appeared to Hippocrates Hippocrates (430(430-350 BC) to be the seat of the soul, “For when the man draws the “For breath (pneuma) into himself, it passes first to the brain…leaving in the brain…whatever has sense and understanding.” 1 The Human Brain Perhaps Perhaps the most conspicuous property of the human brain is that it consists of two hemispheres. Hippocrates wrote in The Hippocrates wrote in The Sacred Sacred Disease, “The human “The brain is double, just like that of all living creatures.” Since Since the two hemispheres appeared symmetrical, no one gave much thought to the idea that we could be of “two minds.” During the Renaissance, Vesalius Began His Anatomical Studies of the Human Brain Since Since human dissections were illegal in ancient Rome, Galen (100) dissected apes and argued that they would be anatomically similar to humans. During During the Renaissance, Vesalius (1541) di (1541) dissected the bodies of executed th criminals. criminals. Vesalius Vesalius described the human brain and realized that many of Galen’s conclusions about human anatomy that were based upon dissections of animals were incorrect. Vesalius Vesalius believed that, in the ventricles ventricles of the brain, the “animal spirits” that originated in the heart combined with the pneuma in the inspired air. Je Je pense, donc je suis, Cogito ergo Sum, I think therefore I am. Rene Rene Descartes believed that our ability to think made us human. Descartes Descartes was also a dualist like Plato dualist and Vesalius and believed that humans have immaterial souls that are separate from the body But he believed that the from the body. But he believed that the mind mind and body joined in the brain at the pineal pineal gland. He He suggested that the pineal gland was the organ that connected the mind to the connected body because he (wrongly) thought, it was unique to humans, single, along the midline of the body, and near the ventricles where ventricles where he believed the “animal spirit” took in sensory information from nerves and through nerves controlled the limbs and organs on both sides of the body. The Brain, not the Heart, is the Seat of the Soul Thomas Thomas Willis also believed that the whole brain was the seat of brain was the immortal soul. The conclusion of this deeply religious man was at odds with the bible the bible, which says in Matthew sa in Matthe 12:34, “…out of the abundance of the heart the mouth speaketh." speaketh." Willis Willis (1664) believed that an anatomical study of the brain would “unlock the secret places “unlock of Man's Mind and look into the living and breathing Chapel of the Deity.” Abnormal Behavior May Result from an Abnormal Brain Willis Willis believed that the immortal soul was not housed in the pineal gland or the ventricles, but in the matter of the whole matter brain, where chemical reactions could chemical take place. He He believed that soul directed the whole brain brain to perform chemical reactions that resulted in our thoughts and behavior. Willis believed that the cause of abnormal thoughts and behaviors could be found by studying the anatomy of the brain. anatomy He He performed autopsies on the brains of autopsies people with epilepsy, migraine headaches and various mental illnesses in order to find correlations correlations between physico-chemical physicoanatomical lesions and mental illness. and mental No Anatomical Correlations with Aspects of the Soul Willis Willis never discovered any correlations between an anatomical lesion in the brain and diseases diseases such as epilepsy, migraines or mental illness. Others Others followed him and looked for a relationship between brain anatomy and aspects of the soul. 2 Franz Gall: The Science of Cranioscopy Franz Franz Gall (1798) thought that the brain was the physical basis of the mind and that the brain was subdivided into regions brain that independently served as the organ responsible for each function of the mind. He remembered one of his childhood hi friends friends had bulging eyes and a very good bulging very memory and he reasoned that the part of the brain that controlled memory must be behind the eyes, and, in his friend, it was so large, that it caused his skull to deform during infant development. Based Based on his idea that "the skull is molded on the brain", Gall started a program called cranioscopy cranioscopy to correlate mental functions with bumps and depressions on the head. The Science of Human Nature Gall (1798) wrote, “My “My purpose is to ascertain the functions of the brain in general, and those of its different parts in particular; to show that it is possible to ascertain different ascertain different dispositions dispositions and inclinations by the elevations and depressions upon the head; and to present, in a clear light, the most important consequences which would result therefrom to medicine, morality, education and legislation— legislation—in a word, to the science of human nature.” Scientific Often Consists of Systematic Data Gathering Followed by Making Inferences from the Correlations. Gall Gall systematically divided people into two groups and then identified the features on their heads that differentiated the two groups. “I “I ranged the quarrelsome on one side and the peaceable on the other, and examined carefully the heads of both. I found that in all the former, the head, immediately behind and on a level with the top of the ears, was much broader than in the latter.” Phrenology While Gall’s idea that the brain is differentiated into differentiated specialized specialized regions is the basis of all neuroscience today, Gall’s former assistant-turned assistantcharlatan Johann Spurzheim, coined the term phrenology to coined the term phrenology to replace replace cranioscopy, moved to the United States and turned a good profit from Boston’s high society by making unwarranted unwarranted generalizations about a person’s personality based upon his reductionist assumption of biological biological determinism. Personal Phrenology Chart A bump in the benevolence bump benevolence region indicated goodness, goodness a gentle character and the presence of a conscience. A depression in this region depression in this region signified cruel person. signified a cruel person. A bump in the veneration bump veneration region region indicated a pious pious person, person, while a depression depression in this region signified an atheist atheist. Do Do your bumps correlate with your character? Benevolence and Veneration: Examples Benevolence Benevolence Veneration Veneration 3 The Phrenology Bandwagon Entrepreneurs, Entrepreneurs, including Orson and Lorenzo Fowler jumped on the on the phrenology phrenology bandwagon. They They founded a scientific society and published a journal. Mark Twain “…I made a small test of phrenology…. I went to Fowler under an assumed name and he assumed examined my elevations and depressions … he found a cavity, in one place; a cavity where a bump would have been in anyone else's ld skull. That cavity, he said was all alone, all by itself, occupying a solitude, and had no opposing bump, however slight in elevation, to modify and ameliorate its perfect completeness and isolation. He startled me by saying that that cavity represented the total absence of the the sense of humor!" Mark Mark Twain “I waited 3 months and went to Mr. Fowler again, heralding my arrival with a card bearing both my name and my nom de guerre….Once more he more he made made a striking discovery-discovery-the cavity was gone, and in its place was a Mount EverestEverest-figuratively speakingspeaking-31,000 feet high, the loftiest bump of humor he had ever encountered in his lifelife-long experience!" Science vs. Pseudoscience Soon Soon others realized that the goal of phrenology was to make money and was not a science aimed at understanding the understanding the relationship relationship between the brain and the mind. When When a science is young, how does one know whether it is scientific, with goals of knowing ourselves, or pseudoscientific, with goals of making money? How is the Correlation of Genes with Disease Traits Similar to the Correlation of Bumps on the Head to Character Traits? Does Size Matter: Is Genius Related to the Size of the Brain? Johann Johann Reil (1809) discovered how to preserve preserve brains with alcohol. This allowed brains to be preserved for scientific study following death. following death. In In 1824, Lord Byron’s brain was measured during an autopsy and it was found that it weighed twenty-five percent twentymore than the average brain and thus it seemed, prima prima facie, that Lord Byron’s genius was a consequence of his large brain. large 4 She walks in beauty, like the night Of cloudless climes and starry skies; And all that 's best of dark and bright Meet in her aspect and her eyes: Thus mellow'd to that tender light Which heaven to gaudy day denies. One shade the more, one ray the less, Had half impair'd the nameless grace Which waves in every raven tress, waves in every raven tress, Or softly lightens o'er her face; Where thoughts serenely sweet express How pure, how dear their dwelling-place. dwellingAnd on that cheek, and o'er that brow, So soft, so calm, yet eloquent, The smiles that win, the tints that glow, But tell of days in goodness spent, A mind at peace with all below, A heart whose love is innocent! Or Is Genius Related to the Convolutions of the Brain? Johann Wagner (1827) noticed that in Ludwig von Beethoven’s brain, “the “the convolutions appear twice as numerous and the as numerous and the fissures fissures twice as deep as in ordinary brains.” Prima facie evidence evidence showed that the brains of talented people were probably more more convoluted and the fissures deeper than in the brains of average brains. Lord Byron Anatomists Couldn’t Get Their Hands on Enough Brains • • www.isoc.org Brains, including those of PierrePierreSimon Laplace, Franz Gall, Johann Spurzheim, Georges Spurzheim, Cuvier, Daniel Webster, Carl Gauss, and Peter Dirichlet were preserved and/or studied in order understand the physicophysicochemical basis of mind. In fact, brains and other anatomical parts were in such demand that body snatching, a body whole new occupation grew out of the anatomist’s desire for brains. Human Dissection: A Fate worse than Death In In the 18th and 19th centuries, the only legal means to get bodies for dissection was for a judge to declare that a criminal committed such a heinous crime, that his body heinous would be dissected after execution. dissected th century, the number of executions However, However, during the 19 was decreasing yet the number of medical schools who needed bodies for dissection was increasing. di At At the time, refrigeration did not exist and legally-obtained legallybodies were not necessarily available when they were needed. Let’s Let’s face it, any would-be-patient would want his/her doctor would-beto have first hand knowledge of the insides of the human body and his/her surgeon to be practiced in the art of surgery; but how do they get the bodies to practice on? The The business of body snatching grew. Grave robbers turned to body snatching since body snatching was lucrative and body only a misdemeanor while grave robbing was a felony. Iron Coffins Protected Cadavers from “the Resurrectionists” 5 Body Snatching in New York On On April 13, 1788, some boys were playing outside a hospital in NYC when a medical student waved to them from a third story window using a dismembered arm of a cadaver. The boys climbed up the building, looked into the laboratory and saw a ghastly scene of dissected and dismembered bodies. One of the boys, whose mother recently died, told his father about the horrific scene. The father ran to the mother’s grave and discovered that it was The empty. Soon a mob of 5000 congregated at the medical school to protest the body snatching practiced by the medical students and a riot ensued. The The next year (1789), New York passed an “Act to prevent the “Act odious practice if digging up and removing, for the purpose of dissection, dead Bodies interred in cemeteries or burial places”. “In “In order that science may not…be injured by preventing the dissection of proper subjects…when any offender shall be convicted of murder, arson or burglary…the court may...add to the judgment that the body…shall be delivered to the surgeon for dissection.” The The Bones Act The The act passed in 1789 still did not solve the problem of supply supply and demand and body snatching from cemeteries as well as obtaining bodies before they were interred by bribing undertakers and cemetery caretakers continued. In In 1854, New York passed an Act to Promote Medical Act Science and Protect Burial Grounds better known as the “Bones Act” which allowed the sale of unclaimed bodies from workhouses, hospitals and prisons for dissection. kh di Proponents Proponents of the act argued that the poor, whose bodies will be donated, get more diseases than the rich and thus as a class will benefit most from new medical knowledge. Moreover, without an Anatomy Act, wealthy premeds would go to medical schools in states that have Anatomy Acts that ensure students of having enough cadavers to dissect. Opponents felt that, Opponents felt after death, the poor should not be treated like felons. In In 1968, the US Congress passed the Uniform Anatomical Uniform Gift Act that governs the bequeathing of a body for medical use and prevents the trafficking of human organs for profit. Michael Michael Mastromarino Is a 21st Century American Body Snatcher In In order for the supply of body parts to keep up with the demand for advanced biomedical transplants, therapies and research, Michael Mastromarino of Biomedical Tissue Services Services secretly harvested and sold body parts from 1000 corpses, including Alistair Cooke’s, from 30 funeral homes in the NYC-NJNYC-NJPhiladelphia area. He He replaced the bones with PVC pipes and stuffed the bodies with trash so that they would be how much is your body worth presentable at wakes. Alistair Cooke www.cnbc.com Body Snatching and the Birth of Modern Surgery BODY WORLDS “All anatomical specimens on display in the BODY WORLDS exhibitions are authentic. They belonged to people who declared during their lifetime that their bodies should be made available after their deaths for the qualification of physicians and the qualification of physicians and the instruction instruction of laypersons. Many donors underscore that by donating their body, they want to be useful to others even after their death. Their selfless donations allow us to gain unique insights into human bodies, which have thus far been reserved for physicians at best. Therefore, we wish to thank the living and deceased body donors.” http://www.bodyworlds.com/en.html http://www.hcgs.net/bodysnatch.html http://www.nls.uk/broadsides/subject.cfm/key/body-snatching 6 After After 35 Years of Anatomical Studies, the Correlations Broke Down On the other hand, bodies used in this exhibit, put together by together by entrepreneurs, came from political prisoners executed in China. ABC ABC News ABC ABC News http://www.bodiestheexhibition.com/ Further anatomical studies of brains showed that there were no correlations between genius and brain weight or the number or depth of the fissures in the brain. Rudolf Wagner (1860) wrote in his Preliminary Study on the Scientific Morphology and Physiology of the Human Brain as the Organ of the Soul: “The question of whether “The the number of folds is especially great in highly gifted or intellectually active individuals cannot be deduced at this point.” He went on to write, “While “While certain brains of richly gifted men rank at the top of the list of brain weights, the fact that the brains of men of comparable significance, such as Gauss and Dupuytren, Dupuytren, can be found in the second 100…can only show the uncertainty of the earlier claim.” Anatomical Studies Continued at Cornell University In the US, the brains that were available to study came from prisons and asylums. Burton Wilder (1889) of Cornell University thought that it would be profitable to study the brains of intellectually-gifted professors intellectually(including my predecessor, Simon H. Gage) and www.nytimes.com started a brain collection. Brain Bequest Agreement “Recognizing the need of studying the brains of educated persons rather than those of the ignorant, criminal or insane, in order to determine their weight, form and fissural pattern, the correlations with bodily and mental powers of various kinds and degrees, and the influences of sex age and inheritance hereby declare influences of sex, age, and inheritance, I hereby declare my wish that, at my death, my brain should be intrusted [sic] to the Cornell Brain Association (when that is organized) or (pending its organization) to the Curator of the collection of human brains in the museum of Cornell University, for scientific uses, and for preservation, as a whole or in part as may be thought best. It is my hope that my family and friends may not oppose the fulfilment [sic] of this my earnest wish.” And how do you quantify intelligence anyhow? 7 Intelligence and Brain Weight Edward Edward Spitzka (1903) divided the brains between those that came from men in the exact sciences, natural natural sciences, fine arts and philosophy as well as government and military. He He found that the average brain weights weights were 1532.0 g, 1444.3 g, 1444.3 1482.2 g and 1490.0 g, respectively. While While they were all greater than the weight of the brain of ordinary men, which was approximately 1348-1398 1348g, the fact that the natural scientists had the lightest brains of the notable people may have caused the natural science community to abandon this line of work! William William McKinley In...
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