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 1901, William McKinley was assassinated by Leon Czolgosz at the Pan at the PanAmerican Exposition in Buffalo, NY and here was another chance to literally dissect the criminal mind. 8 Edward A. Spitzka After Czolgosz was found guilty and electrocuted for his crime in Auburn, NY, Edward A. Spitzka (<) studied his brain and concluded, “…nothing has been “…nothing found in the brain of this assassin that would condone his crime for the reason of mental crime for the reason of mental disease disease due to intrinsic cerebral defect or distortion.” He went on to say that, “It is well known that some forms of psychoses have absolutely no ascertainable anatomical basis; and the assumption has been made that these psychoses depend rather upon circulatory and chemical chemical disturbances.” Neurotransmitters Approximately Approximately 11 years later, the first indication of chemical chemical neurotransmitters was discovered by Otto Loewi in the famous experiment where one heart was stimulated by the pa parasympathetic nervous system, and liquid, taken from the stimulated heart was dripped on another heart. Approximately Approximately 50 years later, the scientific community at large came to accept the fact that neurotransmitters were important, not only in the autonomic autonomic nervous system, but also in brain function. brain Acetylcholine Acetylcholine Noradrenaline The Development of the Nervous System Serotonin Dopamine Glutamate Glycine GammaGammaAminobutyric Acid The inner cell mass gives rise to the ectoderm, from which the nervous system develops. The Ectoderm Gives Rise to the Neural Tube The Neural Tube Differentiates into the Spinal Cord Spinal Cord and and the 100 Billion Neurons in the Brain 9 In General, the Brain has Enlarged throughout Evolution …and there has been a holistic process of encephalization, holistic encephalization in which the volume of the cerebrum has increased and regulatory functions have expanded from the “reptile part” of the brain to the cerebrum. cerebrum. Reminder: Folic Acid is Necessary During Early Pregnancy The The neural tube forms in a fetus 15-21 15days after fertilization, often before a after woman even knows she is pregnant. Without Without sufficient quantities of folic acid, the neural tube will not develop normally and the baby will have spina bifida or sp bifid or other birth defects. For For this reason, the CDC recommends that women who are or may become pregnant ensure that they get sufficient quantities of folic acid (vitamin B9) from foods, fortified breakfast cereals or www.nytimes.com supplements. www.cdc.gov 10 The Central Nervous System (CNS) Includes the Brain and Spinal Cord Using Injuries and Surgery to Localize Some Brain Functions Head Head injuries and surgery (ablations) surgery (ablations) in humans and animals have allowed us to map the functions of specific the functions of specific regions regions of the brain. The The brainstem regulates bodily functions and the forebrain is forebrain is involved in more complex behaviors, including memory, learning, speech, vision, and emotions. emotions. The Left Side of the Brain Controls Communication through Speech Jean Jean Baptiste Bouillaud (1825) and Mark Dax (1836) correlated lesions on the left left side of the brain with the inability inability to speak (aphasia). Later, Later, Paul Broca (1861) performed autopsies on people who had lost the ability to speak and confirmed that aphasia is correlated aphasia with lesions in the left side lesions in left of the brain. The Right Side of the Brain Is Responsible for Self-Image, the Embodiment of the Mind Self- A stroke on the right side of the brain, results in neglect neglect, a person’s inability to realize that the body parts on the left side of the body is theirs. Two, 3.5, 6, and 9 months after a stroke to his right side, an artist regains his “self-image”. self- 11 The Right Side of the Brain Is Responsible for Self-Image, the Embodiment of the Mind SelfThe The sense of self image, the mind’s awareness of its body, or knowing where its limbs are is known as proprioception. proprioception. A feeling that the mind is feeling disembodied can disembodied can come from damage to the right brain (It can damage to the right brain. (It can also also come from damage to the sensory neurons, which come to the brain from toned muscles on each limb, by a viral infection or an overdose of vitamin B6). Alcohol Alcohol impairs the proprioception necessary for driving and a sobriety sobriety test tests your proprioception— proprioception—when your eyes are closed, do you know where your finger and nose are? We Are of Two Minds As As a last resort to treat people with severe epilepsy, the connections, known as the corpus callosum between the left and right hemispheres, were severed. The left and right hemispheres could be The left and right hemispheres could be differentially differentially stimulated using the right eye, ear and hand to stimulate the left hemisphere and the left eye, ear and hand to stimulate the right hemisphere. In In doing these experiments Sperry discovered that the two hemispheres process information differently. Split Brain Game A Stroke of Insight Jill Jill Bolte Taylor, a brain scientist, had a massive stroke on the left side of her brain. She She “recovered” from the stroke stroke and used her personal experience and insight to tell us about the specializations of various regions of the brain and how it is our choice to use our “right mind” or our “left mind”. http://www.ted.com/talks/view/id/229 www.ted.com http://drjilltaylor.com/ 12 The Two Minds Within Our Head Left Brain Thinking Thinking and doing mind Working Working mind Masculine Masculine mind Sensing Sensing mind Judging Judging mind Localization Localization of our individuality (our ego) ego) Controls Controls right facial muscles Right Brain Being Being and feeling mind Vacation Vacation mind Feminine mind Feminine mind Intuitive Intuitive mind Perceiving Perceiving mind At At one with the universe Controls Controls left facial muscles Right Face – Normal Face – Left Face www.rightreading.com Right Face – Normal Face – Left Face Right Face – Normal Face – Left Face www.rightreading.com http://mondovista.com/bicamx.html Roger Sperry (1973) “The main theme to emerge... is that there appear to be two modes of thinking, verbal and nonverbal, represented rather separately in left and right hemispheres hemispheres respectively and that our education system, as well as science in general, tends to neglect the nonverbal form of intellect. What it comes down to is that modern society discriminates against the right hemisphere.” 13 I believe that We Can Use Our Two Minds to Successfully Embrace both the Culture of the Humanities and the Culture of Science www.nytimes.com The Bottom of the Brain Is Responsible for Sensing Danger: The Fight or Flight Response (4Fs) Walter Walter Cannon and Philip Bard systematically removed more and more of the cerebral cortex of cats cerebral cats and and found when they removed the whole cortex, the cats were still able to be emotional to be emotional. When When the cats lacking a cerebral cortex were provoked, they showed the normal fight or flight response. normal They crouched down, arched their back, showed their teeth, and unsheathed their claws. Moreover, their pupils dilated, their hair stood on end and their heart rate and blood pressure increased. The Bottom of the Brain Is Responsible for Sensing Danger: The Fight or Flight Response (4Fs) However, However, when Cannon and Bard removed the bottom of the brain (limbic system), the cats lost their fight or flight response. The The region that includes the thalamus, thalamus, hypothalamus, amygdala, cingulate cortex, and hippocampus regulates the defense response, which includes fright and aggressive feelings. Think Think Before Acting The emotional The emotional response is modulated by the cerebral cerebral (or neo-) neocortex since, without the cerebral cortex the the cerebral cortex, the cats cats were triggered into the fight or flight response by the slightest provocation. The The cerebral cortex cortex tells tells the cat to “think before acting”. The Emotional Brain 14 The Emotional Brain: The High Road and the Low Road Cerebral (Neo-) Cortex Response Ability and Responsibility We We have the ability to choose how we respond to emotional situations. We can contain a situation in our brain or activate the hypothalamus, which hypothalamus, which stimulates stimulates the adrenal glands that flood our body with adrenaline, noradrenaline and cortisol. cortisol. We We can develop the ability to choose the high road. This response This response ability leads to responsibility. responsibility http://www.cns.nyu.edu/ledoux/amygdaloids/index.html Was Charles Whitman’s Brain Tumor Responsible for Turning Him Into a Killer? Charles Charles Whitman was a relatively nice guy until he started shooting people from the tower at the University of Texas in 1966. He killed 14 and wounded 32 people wounded 32 people. Did Did Charles Whitman open fire from the University of Texas observation tower because he had a brain tumor in his limbic his system? Could Could he have stopped his actions? Was he responsible or was the tumor responsible? Books and Movies Emotions and Memory Emotions Emotions have a powerful effect on memory and we memory remember emotionally charged experiences better than than we remember experiences that do not involve strong emotions. The The limbic system is not only involved in emotions, but it is also the seat of memory. Henry Molaison (HM) Henry Henry Molaison (HM) had such a severe case of epilepsy, that when he was 27 his doctor removed the part of the limbic system (the hippocampi in his left and right temporal lobe) left and right temporal lobe). Although Although the surgery brought HM’s epilepsy under control, he was no longer able to able remember the new events that occurred in his life for more than a few seconds. For example, he did not remember his age or that his parents had died. Film www.nytimes.com www.boston.com www.npr.org www.dana.org 15 Prosopagnosia (Face Blindness) Phantoms in the Brain 1-1 Phantoms in the Brain 1-2 Phantoms in the Brain 1-3 Phantoms in the Brain 1-4 Phantoms in the Brain 1-5 Phantoms in the Brain 2-1 Phantoms in the Brain 2-2 Phantoms in the Brain 2-3 Phantoms in the Brain 2-4 Phantoms in the Brain 2-5 When When we see someone we know, we have a conscious cognitive recognition response that takes place in the cortex and an unconscious emotional response that takes place in the limbic system. The The limbic response activates our autonomic nervous system. The emotional response can be measured by a decrease in skin resistance. People People with prosopagnosia elicit the emotional response when they see a familiar face, but cannot consciously remember who the person is. Capgras Syndrome A person with Capgras Syndrome may person think that the people close to him/her have been replaced by similar looking people because they do not elicit the unconscious emotional response initiated by the limbic system even though he/she recognizes someone consciously using the cortex. A person with Capgras Syndrome does person not exhibit a decrease in skin resistance when he/she recognizes a familiar face. Capgras Capgras Syndrome is the converse of prosopagnosia. prosopagnosia. The Frontal Lobe Restrains the Emotions An on-theAn on-the-job explosion in 1848 blew a 13-pound tamping rod 13straight through Phineas Gage's head. Unbelievably, Unbelievably, the well-liked wellconstruction foreman who was construction foreman, who was a nice, nice, energetic, smart and persistent businessman before the accident, remained conscious. Immediately Immediately after the accident, he was able to talk and even walked to the cart that took him to Cavendish, Vermont where he was treated by Dr. John Harlow. Joseph Capgras Dr. Dr. Harlow and Phineas Gage According to Dr. Harlow, as a result of the brain injury, Gage's personality changed drastically: “Gage “Gage was fitful irreverent was fitful, irreverent, indulging at times in the grossest profanity (which was not previously his custom), manifesting but little deference for his fellows….” Phineas Phineas Gage Memorial, Cavendish, VT After the accident, Gage’s “…mind was radically changed, so decidedly that his friends and acquaintances said he was 'no longer Gage'.” longer Gage 16 The Brain Is Flexible, Somewhat Holistic and Has the Capability to Reorganize Remove oneRemove one-half of the brain to alleviate severe seizure disorders. Hemispherectomized Hemispherectomized patients recover relatively quickly with undiminished intellectual undiminished intellectual capabilities, capabilities, although the half of the body becomes paralyzed. The The regions of the brain may normally normally be specialized for certain higher order functions, however, the brain is flexible and flexible has the capability to reorganize itself when necessary. Localizing Localizing Brain Functions with BOLD-fMRI BOLDBlood Blood Oxygen Level Dependent Functional MRI (BOLD-fMRI) (BOLD-fMRI) maps the distribution of oxygenated oxygenated hemoglobin. Because Because active neurons require increased blood flow Magnetic increased blood flow, Magnetic Resonance Resonance Imaging is used to localize localize brain function. Interpretation of BOLDInterpretation of BOLD-fMRI data is subjective because the subjective regions of increased blood flow are relative and comparisons must be made between brains of different sizes and with different convolutions. http://users.fmrib.ox.ac.uk/~peterj/lectures/miccai99/sld010.htm BOLDBOLD-fMRI and Deception hwww.cephoscorp.com noliemri.com Langleben Langleben et al (2002) can detect liars by scanning the brain using BOLD-fMRI. BOLDhttp://www.noliemri.com/ http://www.cephoscorp.com/index.htm 17 BOLD fMRI: Mapping a Lie fMRI: fMRI in Court (November 2009) Dateline. “It was a courtroom first. “It Late last year, an Illinois judge allowed functional magneticmagneticresonance imaging (fMRI) as (fMRI) evidence during the sentencing phase of a murder trial. Defense attorneys argued that the scan scan showed signs of mental illness and and hoped it would convince the jury to show mercy. It didn’t. They sentenced Brian Dugan (→) to death for killing a 10-year-old girl.” 10-yearhttp://news.sciencemag.org/scienceinsider/2009/11/fmri-evidence-u.html On this map, activity in blue areas suggests a truthful response, red a lie. Assumption: lying requires more oxygenated blood (red) than telling the truth (blue). Is Society Prepared for BOLD- fMRI? BOLD- fMRI? Privacy Concerns: Does a person have an alienable right to keep his or her subjective thoughts private? Will remote pr Will remo sensing fMRIs be used to monitor airports, classrooms, etc? Will parents use BOLD-fMRI to BOLDsee what is on their child’s mind? The The Big Questions in Brain Research Mind Mind vs. brain: Are Are the mind (cognition/behavior) and brain (physical substance) separate (dualist) or unified (monist) entities? Localism Localism vs. holism: Do Do regions of the brain have specific functions (localism) or does the brain function as fairly undifferentiated whole (holism)? Could the brain function at both levels? Nature Nature of neural communication: Is Is the mind completely "created" by the brain? Can consciousness be reduced to neurons? Is there a soul that exists beyond the neurons? Chance Chance Favors a Prepared Mind “The “The seeds of great discoveries are constantly floating around us, but they only take root in minds well prepared to receive them.” Joseph Henry Henry - “Dans “Dans les champs de ‘l’observation, le hasard ne favorise que les esprits prepares.” That is, “Chance That Favors a Prepared Mind.” - Louis Pasteur 18 Albert Szent-Gyorgyi Szent“A discovery is said to be an accident meeting accident meeting a prepared prepared mind." -Albert Szent-Gyorgyi Szent- 19 ...
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