4-14-10 The Nervous System -Electricity-color

4-14-10 The Nervous System -Electricity-color - Clicker...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Clicker Question Saving one’s life sometimes requires organ transplants. Body snatching and organ trafficking result when the supply of donor organs cannot keep up with the demand. When it comes to organs and organ donations, I _________ accept a donated organ if needed one to live and if I needed one to live and I _________ to donate my to donate my organs organs when I die. A) would, choose B) would, choose not C) would not, choose D) would not, choose not E) I need a brain transplant now! Where are we? The The last two times I discussed… discussed… How How the five sense organs deconstruct the real world of tastes, smells, pressures, temperatures, sights and sounds and send messages to the brain. The The limited success of anatomical studies aimed at localizing aspects of the mind within the brain. Today I will discuss… di the studies that show that the nervous impulse is electrical and show that electrical impulses can be used to localize brain functions. how how our knowledge of the electrical impulse can be used to design equipment that can send messages about the real world to the brain and respond to messages form the brain. Next Next time I will discuss how individual neurons generate and respond to electrical signals. The Nervous System Coordinates the Coupling of Stimulus to Response at an Organismal Level The nervous The nervous system senses many varied stimuli stimuli and triggers an and triggers an appropriate response response. Th The nervous system builds upon the cellular stimuluscellular stimulusresponse system. The The nerves are part of a complex complex network that allows rapid communication communication and coordination between all parts of the body. The Peripheral Nervous System Includes the Afferent Nerves That Bring in Sensory Information to the CNS and Efferent Nerves that Control Skeletal Muscle Contraction and Tone The Peripheral Nervous System also Consists of the Autonomic Nervous System, which includes the Parasympathetic and Sympathetic Nerves There There Is a Division of Labor in the Central Nervous System Rest and Digest Fight or Flight Some simple reflex responses are regulated by the spinal reflex cord and more complex responses are regulated by the brain. 1 Reflexes Subject to Free Will Now Now voluntarily will your quadriceps to relax and the hamstring to contract. Try to induce the Try to induce the patellar patellar reflex response. You can’t— can’t— even through the lower leg has even more room to move. Voluntary Voluntary actions can override involuntary reflexes. Induce Induce the patellar reflex response by hitting the patellar patellar tendon. The quadriceps contract and the knee jerks. quadriceps contract When When the quadriceps contract, the hamstring muscles relax. hamstring The The sensory neuron not only stimulates the motor neuron that sends a excitatory message to the quadriceps muscle that excitatory causes it to contract, but also stimulates an interneuron that interneuron sends an inhibitory message to the hamstring muscle which inhibitory causes it to relax. Much of the Experimentation Aimed at Understanding the Workings of the Nervous System Involved Vivisection. Francois Francois Magendie (1816) was a brilliant but brutal and callous vivisectionist vivisectionist. In order to understand the function of each understand the function of each nerve, nerve, he cut the nerve and observed the animal’s response to stimuli. He began by studying the role of the anterior (ventral) and posterior (dorsal) nerves in the spinal cord in reflex responses reflex of puppies. Claude Bernard's (1865) Writings on Vivisection When When he cut the anterior (ventral) nerves of the spinal cord, anterior the puppy could still feel the pain inflicted by Magendie, but the puppy could not move its leg in response to the pain. Magendie concluded that the anterior nerves were primarily concerned anterior were with movement. movement When When he cut the posterior (dorsal) nerves of the spinal cord, posterior the leg would not move in response to a painful stimulus, even though it would move when he stimulated the anterior nerve with electricity. He concluded that the posterior nerves were posterior primarily concerned with sensation. sensation Ventral root root Dorsal root The nervous system acted as a unidirectional circuit. 2 Balancing the Costs and Benefits of Animal Use According to Jane Goodall, “If we…see a peasant beating an emaciated old donkey, forcing it to pull an oversize load…we are shocked and outraged. But taking an infant chimpanzee from his mother arms, locking him into the bleak mother’s arms, locking him into the bleak world world of the laboratory, injecting him with human diseases—this if done in the diseases— name of Science, is not regarded as cruelty…Why is one more cruel than the other? Only because science has come Only to be venerated, and because scientists are assumed to be acting for the good of mankind, while the peasant is selfishly punishing a poor animal for his own gain.” Benefits of Animal Experimentation Understanding Understanding the structure and functions of organs (e.g. Minkowski and the pancreas of a dog). Discovery Discovery and isolation of hormones (e.g. Bayliss and Starling, secretin and the old brown dog). Organ transplants (Alexis Carrel, who won the Nobel Organ transplants (Alexis Carrel, who won the Nobel Prize Prize in 1912, performed transplants on dogs). Drug Drug testing: Animals are used primarily in ADMET tests. How How is the drug Absorbed into the body? How How it is Distributed to the tissues? How How does the body Metabolize it? How How does the body Eliminate it? Are Are there Toxic effects? Goodall and Prosopagnosia How Can We Be More Humane? Marshall Hall (1830s): On Animal Experimentation • The Tree of Life In order to be more humane, biologists do experiments on taxa taxa, including bacteria, yeast, plants, fruit flies, worms, zebra fish, mice, rats, cats and chimps that have no or smaller brains and are considered to brains and are considered to be less be less sentient than than humans. humans. Depending on the ubiquity of ubiquity the process being studied and the evolutionary distance evolutionary from from humans, the results will be more or less transferable to humans and in the end, human research is inevitable. Experiments Experiments should not be performed if the necessary information could be obtained by observations observations. Experiments Experiments should have a clearly defined clearly and obtainable objective. Scientists Scientists should be well-informed about the wellwork work of their predecessors and peers in order to avoid unnecessary repetition of an avoid experiment. Experiments Experiments should be carried out with the least least possible infliction of suffering—often through the use of lower, less sentient use animals. Experiments Experiments should be performed under circumstances that provide the clearest possible results, thereby diminishing the diminishing need for repetition of experiments. • More More Humane Experimentation The basic ethical principles of human human experimentation outlined in the Belmont Report include, respect (informed consent), consent), beneficence beneficence (maximize benefits and minimize harm) and justice (who benefits and who bears the burden of medical research). http://www.hhs.gov/ohrp/humansubjects/guidance/belmont.htm http://www.ethologicalethics.org/ 3 The Brain and Spinal Cord Integrate the Various Electrical Sensory Inputs and Electrically Stimulate the Movement of Muscles and Secretion of Glands Electricity In the 1700s, electrical machines could produce electricity and Leyden jars could store it. People asked, “What can we do with electricity?” It was used for science and entertainment. Electricity, Electricity, Weather and Health When Benjamin When Benjamin Franklin (1752) flew a kite in a thunderstorm, he was able to show that lightning was electric when a spark traveled down the wet kite string to a key. It It seemed like a good idea to lik id apply apply electricity to medicine. After all, weather and health weather had always been related in people’s minds, and if lightning, lightning an awesome element of the weather was electric, then electric electricity must electricity must also be related to health. health Lightning Causes a Frog’s Leg to Twitch In In order to see if “natural” electricity could cause the “natural” frog’s muscles to twitch, Luigi Galvani connected a frog to a wire running to a lightning rod. Can Peaceful Electricity Cause a Frog’s Leg to Twitch? Galvani (1791) wrote, “The “The effects of stormy atmospheric electricity atmospheric electricity having having been tested. My heart burned with desire to test also the power of peaceful everyday electricity.” Two Two Different Metals Can Also Cause a Frog’s Leg to Twitch Galvani Galvani often suspended dead frogs by brass hooks from the iron brass iron fence in his garden. Galvani Galvani noticed that when the brass hook touched the iron railing by accident, the muscle would twitch. id th With prepared With a prepared mind, he showed that when he touched a frog muscle with two different metals, the muscle would twitch and that the magnitude of the twitch depended on the pair of metals used. In In fact, he set the metals up in a way that the frog would dance! 4 Animal Electricity Galvani Galvani (1791) concluded that frogs and indeed all animals could generate electricity and this animal electricity animal conducted conducted a current in the same way as artificial electricity. From From all his experiments, Galvani surmised that under under normal conditions, the electric fluid is generated in the brain (after being extracted from the blood), travels down the nerves, and stimulates the muscles. Alessandro Volta Denies the Existence of Animal Electricity Interestingly, Alessandro Interestingly, Alessandro Volta (1800), Galvani’s rival concluded that the generation of electricity has nothing to do with the animal and that any two two different metals will generate electricity when they are placed in a salt solution, salt similar to the salty solution that makes up cytoplasm. Volta Volta used these results to invent the battery, which at battery that time was known as the Voltaic pile. Galvani and Volta Were Both Partly Right Like Like the Six Men from Indostan looking at the elephant, Galvani and Volta were both partially right. Galvani was partially right Galvani was partially right because each because each cell can and does generate electricity. Volta Volta was partially right because abiotically-derived abioticallyelectrical currents generated by two different metals in a salt solution (e.g. a battery) (e.g. can excite a muscle to contract. John Aldini: Galvani’s Nephew and Protector Giovanni (John) Aldini (1803), Luigi Galvini’s nephew, wanted to protect his uncle’s reputation reputation from Volta’s attacks and continued his uncle’s experiments in very dramatic ways. He began by repeating the experiments on frogs…. 5 Then went on to mammals…. And then…. John Aldini (1803) Aldini Aldini connected the Voltaic pile between the spinal fluid and the forearm of Mr. George Forster. “In “In consequence of this arrangement, the foreforearm was raised, to the great astonishment of those who were present.” 6 John Aldini To get fresh bodies “…I was “…I obliged, if I may be allowed the expression, to place myself under the scaffold, near the axe of justice, to receive the yet yet bleeding bodies of unfortunate criminals, criminals, the only subjects proper for my experiments. In consequence of an application made for that purpose, I obtained from Government the bodies of two brigands, who were decapitated at Bologna in the month of January 1802.” John Aldini “As both these individuals had been very young, and of a robust constitution, and as the parts exhibited the utmost soundness, I entertained strong hopes of obtaining the happiest results from my proposed researches. Though my Th accustomed accustomed to a more tranquil kind of operations in my closet, and little acquainted with anatomical dissections, the love of truth, and a desire to throw some light on the system of Galvanism, overcame all my repugnance, and I proceeded to the following experiments.” John Aldini “I placed the two heads in a straight line on a table, in such a manner that the sections of the neck were brought into communication merely by the animal fluids. When thus animal fluids. When thus arranged, arranged, I formed an arc from the pile to the right ear of one head and to the left ear of the other, and saw with astonishment the two heads make horrid grimaces; so that the spectators, who had no suspicion of such a result, were actually frightened.” John Aldini (1803) “The unenlightened part of mankind are apt to entertain a prejudice against those, however laudable their motives, who attempt to perform experiments on dead subjects; and the vulgar on dead subjects; and the vulgar in in general even attach a sort of odium to the common practice of anatomical dissection. It is, however, an incontrovertible fact, that such researches in modern times have proved a source of the most valuable information….” John John Aldini (1803) “Enlightened legislators have been sensible of this truth; truth; and therefore it has been wisely ordained by the British laws, which are founded on the basis of humanity and [sic] public benefit, that the bodies of those who during life violated one of the most sacred rights of mankind, should after execution be devoted to a purpose which might make some atonement for their crime by rendering their remains beneficial to the society they offended.” 7 John Aldini Aldini Cures Mental Illness with Electricity “In consequence of a long series of painful and disagreeable experiments made on myself, I was induced to entertain great hopes from this remedy. I applied it to my ears and to different parts of the head, in order that I might form a just estimation of its power and influence on the brain. It is well known that the strength and energy of the operations of the mind depend on strength and energy of the operations of the mind depend on the the state of the functions of the brain. It is well known also, that a violent fall, or strong impression on the head, has often occasioned great variations in the intellectual faculties. By such accidents some have entirely lost the power of imagination; while, on the other hand, some have acquired very great talents, or emerged from a state of complete stupidity. These considerations gave me reason to hope that the power of galvanism might perhaps be able to produce a salutary change in the brain in cases of melancholy madness.” “It is painful to a philosopher to reflect, that his doubts cannot be cleared up until new victims shall fall under the sword of justice: but the hope that his researches may lead to some new discovery beneficial to mankind, in a philosophical point of view, lessens in a certain measure the disagreeable sensations excited by these melancholy scenes.” John Aldini: Electroshock Therapy “I “I announced the complete cure of two lunatics.” Aldini’s work was Aldini work was the the beginning of electroshock or electroconvulsive therapies used to treat mental illness. Andrew Ure Continued Experimenting on Executed Criminals “…one conducting rod being applied to it [the forehead], the other to the heel, most extraordinary grimaces were exhibited every time that the electric discharges were made made….Every muscle in his in his countenance countenance was simultaneously thrown into fearful action: rage, horror, despair, anguish and ghastly smiles united their hideous expression in the murderer’s face…. At this period several of the spectators were forced to leave the apartment from terror or sickness, and one gentleman fainted.” 8 The Power of Electricity “It is well known that cases of deathdeath-like lethargy, or suspended animation, from disease and accidents, have occurred, where life has returned, after longer interruption of its functions…. It is probable, that that a judiciously directed galvanic experiment, will…restore the activity of the vital functions….Fair hopes may be formed of deriving extensive benefit from galvanism; and of raising this wonderful agent to its expected rank, among the ministers of health and life to man.” FRANKENSTEIN While staying at Lord Byron’s villa, Mary Shelley became became aware of Aldini’s experiments. She published her novel, Frankenstein in in 1818. -Andrew Ure (1819) Muscles that Express our Emotions Move in Response to Electricity Guillaume Guillaume Duchenne could induce smiling by applying electricity to a person’s person’s face. A real smile that includes real movements of the eye muscles as well as movements of the mouth muscles is known as a Duchenne smile. Our Facial Muscles are an Indication of the Electricity that is Running through our Minds Facial Muscles can be Used to Read Someone’s Mind “The Department of Homeland Security is developing - Future Attribute Screening Technology (FAST) Technology (FAST) … that is that is grounded grounded in research on human behavior and psychophysiology ….The aim is…to increase the accuracy and validity of identifying persons with malintent (the intent or desire to cause harm).” www.dhs.gov 9 Facial Muscles are Used to Display Emotions It is necessary for animators at PIXAR to know PIXAR to know how how to form faces that represent emotions accurately. Physiological Effects Induced by the Voluntary Movement of Facial Muscles While developing F.A.C.S., a technique for measuring facial muscle movement, Paul Ekman and Wallace Paul Ekman and Wallace Friesen Friesen realized that they experienced strong physical sensations when they contracted their facial muscles to produce facial expressions characteristic of various emotions. Paul Ekman New York Times We Can Consciously Control Our Autonomic Nervous System (and Perhaps our Emotions) Robert Robert Levenson, Paul Ekman and Wallace Friesen (1990) gave subjects (actors and other researchers) muscle-by-muscle muscle-byinstructions on how to produce instructions on how to produce facial facial expressions of anger, disgust, fear, happiness, sadness and surprise. Levenson Levenson et al. measured physiological factors such as heart beat, skin temperature, skin conductance and movement. Expressions of Anger and Fear increase the heart rate. Anger increases blood flow to the hands. Fear decreases blood flow to the hands. 66% of the subjects actually began to feel the emotion linked to the facial expression they were mimicking. 10 The Nervous Signal is Electrical The Nervous Signal is Electrical Emil Du Bois-Reymond Bois(1848) wrote, “If I do not wrote, “If greatly deceive myself, I have succeeded in realizing in full actuality realizing in full actuality (albeit (albeit under a slightly different aspect) the hundred years’ dream of physicists and physiologists, to wit, the the identification of the nervous principle with electricity.” Emil Du Bois-Reymond (1848), a student of Johannes BoisMuller, placed an electrode at a cut end of a peripheral nerve and another along its surface and, using a galvanometer, detected an electrical current that accompanied the nerve impulse. impulse. Using Using Electricity to Localize Motor Control in the Brain Eduard Eduard Hitzig (1860s), a doctor working at a Prussian military hospital, experimented experimented on patients who had pieces of their skulls blown away in battle. He He stimulated their exposed brains with wires connected to a battery and discovered discovered that weak electric shocks, applied to regions at the back of the brain, caused the patients' eyes to move. He He further localized regions of the brain that control specific muscles by electrically stimulating the cerebral cortex of dogs. These These experiments unified Franz Gall’s theory of cortical localization and functional specialization with Luigi Galvani’s electrical messenger. Epilepsy: The Generation of Uncontrolled Electrical Discharges by Scar Tissue in the Gray Matter of the Brain John John Hughlings Jackson (1870s) approached the problem of cortical localization, not through experimentation but experimentation but through careful observation. observation He paid attention to his wife’s epileptic seizures. He noticed that every one of her seizures followed the noticed that every one of her seizures followed the same same pattern. It would start at her hands, move up to her wrist, her shoulder, her face and would then affect the leg on the same side of her body. Hughlings Hughlings Jackson believed that the seizures were caused by electrical discharges within the brain electrical and and radiated out from the initiation point to activate regions that controlled specific muscles. Since the pattern never varied, Jackson thought that the way the brain is organized must also be set. John Hughlings Jackson Wilder Penfield (1950s) Wilder Wilder Penfield opened up the temporal lobes of epileptics. He He then stimulated various regions of the brain to find the region where the epileptic electrical discharge began. Then he removed this region of the brain to eliminate the epileptic seizures. However, However, what he found, when he stimulated the patients, astonished him. 11 The Physical Basis of Memory While While operating on epileptic patients, Wilder Penfield applied electric currents to the surface of the brains of fully conscious although anaesthetized patients. During the operations the patients During the operations the patients expressed expressed what they were experiencing. Electrical Electrical stimulation of some areas triggered various memories and even caused someone to hear a song as if it was being played in the operating room. Penfield had found the physical basis for memory. http://www.histori.ca/minutes/minute.do?id=10211 Motor Homunculus While While probing the brains of epileptics with an electric probe, Wilder Penfield noticed that various parts of the bod mo body moved and and consequently consequently mapped the regions that control the motor functions of the body. He He created the “motor homunculus” to express the functional specialization of various regions in the brain. Somatosensory Somatosensory Homunculus Likewise, Likewise, Penfield mapped the regions of the brain that, when stimulated, give rise to the feeling that a particular part of the body was touched. Stimulation Stimulation of these regions of the brain may give rise to the feeling of having a phantom limb. This This work further supported the idea that particular functions are localized in specific regions of the brain. 12 From Horror to Happiness Bioelectrical and Biomechanical Engineering as an Alternative to Eugenics In The World, the Flesh, and The the Devil, John Desmond Bernal (1926), proposed “delicate “delicate surgery to attach nerves permanently to nerves permanently to apparatus apparatus which will either send messages to the nerves or receive them.” as an alternative to “the perfect “the man such as the doctors, the eugenists and the public health officers between them hope to make of humanity….” While While physical investigations of the electrical nature of life were literally horrible, and they gave rise to Mary Shelley’s book, Frankenstein, they have also resulted Frankenstein in remarkable inventions that increase the quality of individuals’ lives. Such Such inventions include, bionic limbs, ears and eyes. John Desmond Bernal “Normal man is an evolutionary dead end; mechanical man apparently man, apparently a break break in organic evolution, is actually more in the true tradition of a further evolution.” Manfred Clynes (1960): “Cyborg” “Space “Space travel challenges mankind…spiritually…it invites man to take an active part in…evolution…. What What are some of the devices necessary for creating self-regulating man-machine selfmansystems? This self-regulation selfmust…cooperate with the body’s own autonomous homeostatic controls….The Cyborg deliberately incorporates exogenous components extending the self-regulatory selfcontrol function of the organism in order to adapt it to new environments…. The The purpose of the Cyborg, as well as his Cyborg, own homeostatic systems, is to provide an organizational system in which such robotrobotlike problems are taken care of automatically and unconsciously, leaving man free to explore, to create, to think, and to feel.” Of course the same goals apply on earth and an arm or a leg or any organ or part of an organ can be replaced with hardware that will hardware perform the physiological function physiological function of of the limb or organ and software that will software regulate the hardware and integrate its actions with those of the rest of the body, including the brain. 13 Liberating Technologies Inc. Created The Boston Digital Arm for Jessie Sullivan and Claudia Mitchell, the First Six Million Dollar Man and Bionic Woman Boston Digital Arm Dr. Dr. Todd Kuiken transplanted the motor motor neurons from the arm to the chest. These nerves on the chest signal electrodes placed on the chest. The micro computer in the The micro-computer in the Boston Boston Digital Arm detects these signals and controls the speed and directions of the eight prosthetic motors to give relatively natural movements. In In the future, electrodes in the hand will send signals to the sensory neurons in sensory the chest, where they will be perceived as touch. www.liberatingtech.com Touch Touch Bionics: Lindsay Block The i-LIMB Hand is controlled by a two-input twomyoelectric (muscle signal) generated by the muscles in the remaining portion of the patient’s limb. limb. www.nytimes.com www.youtube.com www.touchbionics.com 14 John German Donald McKillop 15 Otto Bock SensorHand Speed Tiny Silicon Chip Produced by Cyberkinetics Inc. Implanted in Brain Allows You to Operate Computers with your Mind www.ottobock.com Video Sensor Implanted in Your Brain Allows You to Move a Cursor with Your Mind A Cochlear Implant Makes it Possible for Michael Chorost to Hear http://www.exploratorium.edu/listen/lg_michael_video.php Braingate Braingate-2 http://www.hearingresearch.org/ Boston Scientific, Cochlear and MedMed-El Make Cochlear Implants Boston Scientific Cochlear Med-El http://www.michaelchorost.com/ 16 Bionic Vision A Solution for Retinitis Pigmentosa, the Pigmentosa, Progressive Degeneration of the Retina A camera in a pair of glasses captures the image. The image is processed and transmitted to a wafer-thin electronic waferreceiver receiver and electrode panel implanted on the patient’s retina. The electrodes stimulate the remaining retinal nerves, sending electrical pulses along the optic nerve to the brain. Peter Lane http://abcnews.go.com/Video/playerIndex?id=4343506&affil=wsyr ngm.nationalgeographic.com www.2-sight.com www.brailleworks.com www.bionicvision.org.au Stuart Meloy Discovers the Orgasmatron Stuart Meloy, Stuart Meloy, of Piedmont Anesthesia and Pain Consultants was performing a painpain-relief operation on a woman's spine by implanting electrodes and using electrical pulses to modify the pain signals passing along the nerves. The The patient, who remained conscious during the operation to help Meloy find during the operation to help Meloy find the the best position for the electrodes, started moaning and hyperventilating and then said, “You're going to have to “You're teach my husband to do that." Meloy Meloy discovered a way to electronically induce an orgasm. He implants an electronic device that attaches to the spinal cord under a person’s skin. The $17,000 device triggers an orgasm when it is activated by a hand-held handremote control. http://www.metacafe.com/watch/54401/orgasmatron/ The Orgasmatron (Sleeper, 1973) http://www.latimes.com/features/health/2008 17 Androids LightLight-Activated Neurons Is it possible to use light to activate certain neurons in certain neurons in the the brain to treat brain diseases and mental illnesses? Japanese Female Android www.wired.com Plants are Fantastic at Responding to Light Chlamydomonas Step-Up StepPhotophobic Response Step-Up Photophobic Response Initiated by a 10 μs Flash of Green Light The Ability to Swim Backwards in Response to Light Requires Calcium 10-8 10-6 10-4 M Ca2+ 18 Low calcium High calcium How many Calcium Ions are Needed to Change from a Ciliary to a Flagellar Beat? The The volume of the cilium is 7.4 x 10-19 m3. 0.1 0.1 μM = 10-4 mol/m3 (10 (10-4 mol/m3)(7.4 x 10-19 m3) (6.02 10 (6 x 1023 Ca2+/mol) = 44 Ca2+ 10 1 μM = 10-3 mol/m3 = 443 Ca2+ The The entry of 399 Ca2+ into the cilium causes the change from ciliary to flagellar beat. How many Ca2+ channels are needed within to pass the 399 Ca2+ within 0.5 s? A Ca2+ channel Ca passes 106 Ca2+/s. Only Only one channel needs to be activated to change from a ciliary to a flagellar beat. How many photons are needed to activate a Ca2+ channel? A single channel single requires about 10-19 J to become activated. A photon of 510 nm light photon has 3.9 x 10-19 J of 10 of energy energy (E = hc/λ). hc/ It It may only take one photon absorbed by channelrhodopsin to change from a ciliary to a flagellar beat. Karl Karl Deisseroth (2007) Transformed Neurons with Channelrhodopsin so that They Became Light Sensitive 19 Optogenetics Sham Electrical Stimulation Experiments Find that People Tend Not to Question Authority The The subjects in Stanley Milgram’s (1961) Stanley experiment believed they were part of an experiment to test the relationship between punishment and learning. He He instructed the participants to shock a learner by pressing a lever on a machine each time the learner made a mistake. Each Each subsequent error led to an increase in the intensity of the shock from 15 to 450 volts. The The electrical machine was actually a prop and the learner an actor who did not get shocked. The The result: A majority of the subjects obeyed to the end, believing they were delivering 450 volt shocks simply because they were told by the authority figure to do so. By By transforming certain neurons in the brain with genes that encode plant pigments, we can make those normally lightlightinsensitive brain neurons light sensitive. In In this way, they can be selectively activated by light from lightlightemitting diodes (LEDs) flowing through thin optical fibers. (LEDs) Perhaps Perhaps this technique will be valuable to treating brain diseases and mental illnesses. seedmagazine.com Stanley Milgram showed us that as people we tend to obey authority. Richard Feynman encourages us to question authority. “This freedom to doubt is an important matter in the sciences…. It was born of struggle. It was born of a struggle. It was a struggle to be permitted to doubt, to be unsure. And I do not want us to forget the importance of the struggle…. I feel a responsibility as a scientist who knows the great value of a satisfactory philosophy of ignorance….” Obedience to Authority—The Authority— Original Movie by Stanley Milgram Clip of Milgram Experiment 20 Thatige Skepsis “An Active Skepticism is that which unceasingly that which unceasingly strives strives to overcome itself and by well directed Research to attain to a kind of Conditional Certainty.” Thomas H. Huxley Questioning Authority Scientists Scientists have trouble in questioning the authority of the dominant group. Conrad Conrad H. Waddington (1977 (1977), who came up with the the concept of epigenetics, epigenetics, proposed in his book Tools Tools for Thought, the acronym “COWDUNG” to signify the Conventional Wisdom of the Dominant Group. Thomas Gold Skepticism Skepticism “A critical attitude is clearly required of every scientist…. Whenever the established ideas are accepted uncritically, but conflicting new evidence is conflicting new evidence is brushed brushed aside and not reported because it does not fit, then that particular science is in deep trouble— trouble— and it has happened quite often in the historical past.” Skepticism The greatest value The greatest value of of science is the freedom to doubt! Richard Feynman 21 ...
View Full Document

Ask a homework question - tutors are online