RICHARD J BAROHN M D GERTRUDE AND DEWEY
RICHARD J. BAROHN, M. D. GERTRUDE AND DEWEY ZIEGLER PROFESSOR OF NEUROLOGY THE UNIVERSITY OF KANSAS MEDICAL CENTER History of Neurology Ivan Pavlov M. D. and The Conditioned Reflex
Ivan Petrovich Pavlov M. D. 1849 -1936 § Born in a Central Russian farming village, Ryazan. Father was a Russian orthodox priest-expected Pavlov to enter into local seminary § Received free education (primary and seminary) made possible by Czar Alexander II for gifted/poor students § In seminary, he read Darwin “Origins” and Ivan Sechenov’s “Reflexes of the Brain” § Left seminary (without graduating), enrolled at the Univ. of St. Petersburg where he studied Medicine/Natural Science § Sechenov was the Professor of physiology § Graduated in 1875 § Research was his goal, not to practice § Won 2 year fellowship in Germany (Leipzig/Breslau) investigating circulation and gastric secretion § Studied experimental pharmacology back in St. Petersburg § Doctorate on centrifugal nerves of the heart (discovered independently of Gaskel special tropic nerves of the heart § 1891 -Professor of Physiology at the Institute of Experimental Medicine § Researched until he died of double pneumonia in 1936, he was 86 years old 2
IVAN PAVLOV M. D. 4. Research in 4 Fields: Cardiac physiology Digestion Central Nervous System Psychophysiology Ø In 1890 s: Digestion § Surgically created dog’s stomach a pouch with a fistula implanted (Pavlov's pouch) in order to observe secretion of gastric juices when dogs began to eat without contamination of food. § These findings about gastric secretions led to the Nobel Prize in Medicine and Physiology in the 1904 book The Work of The Digestive Glands (right), published in 1897 in Russia and translated to English in 1902. § In 1907, became full member in the Russian Academy of Sciences. 1. 2. 3. 3
IVAN PAVLOV M. D. 1897 -1900 : Observed the following in the course of gastric reflex research § Dogs would secrete gastric juices and saliva when saw or heard keeperinitially this was considered a nuisance § Recognized there must be an explanation since there was no food in the dogs mouth. The dog realized mealtime was near § Thoughts produced secretions § A “psychic secretion” is due to a reflex in the brain caused by the stimulus of sight or sound of the person who was usually bringing food. 4
Ivan Pavlov M. D. Early Experiments of the Conditioned Reflex § 1902 -Began to study how and when such a stimulus was capable of causing secretions. § Instead of stomach pouch with fistula he implanted a fistula in salivary gland to a collection/recording device § Dogs trained to stand on the tablepraised, pelted or fed § Faced wall w/ window; bowl of food could be placed in § When dog had food in it’s mouthsaliva flowed ü FOOD=UNCONDITIONED STIMULUS ü SALIVARY RESPONSE=UNCONDITIONED REFLEX 5
IVAN PAVLOV M. D. SALIVARY RESPONSE=CONDITIONED REFLEX SOUND = CONDITIONED STIMULUS Sound (ring, bell, buzzer) preceded food drop in bowl by various amounts of time, usually 5 to 30 seconds. After a number of sequences, sound alone caused saliva to flow. 6
IVAN PAVLOV M. D. Conditioned Reflex Many variations on experiment Light instead of sound Change length of time between neutral stimulus and food drop § § § Did not believe this was a psychological process-but a physiologic one. Claimed indebtedness to Sechenov and Descartes (below) Pavlov considered unconditional response a brain Neutral stimulus could be made into reflex conditioned stimulus w/ varying degrees of ease Conditioned response was a result of new reflexive pathways created by conditioning process in the Neutral odor might require >20 cortex pairings Early Neuroplasticity concept Rotation of object in dogs view might require >5 pairings Sounding bizarre might require only 1 7
IVAN PAVLOV M. D. Theory of Localized Brain Reflexes From Conditioning Largely ignored except in Russia / USSR Pavlov believed he identified fundamental unit of learning in animals and humans All learned behavior was “a long chain of conditioned reflexes” Ø Karl Lashley, (right) one of the world’s foremost brain researchers in U. S. , tried to disprove Pavlov’s experiments: § Destroyed brain areas in rats who had been conditioned § Learned maze behavior with rats to understand how memory occurred § Found loss of ability to learn related not to the destruction of a specific area but total amount destroyed 8
Ivan Pavlov And The Creation of Behaviorism § Remained unknown for years in the West, even though Pavlov mentioned conditioning in 1904 Novel Speech § In 1908, Robert Yerkes discovered Pavlov in German journals, wrote a review in “Psychological Bulletin” § James Watson (Hopkins), Founder of Behaviorism in USA, discovered Pavlov’s work in 1916. He considered the Conditioned Reflex “the keystone of the arch” of behaviorist theory and methodology § From 1920 s to 1960 s, behaviorism was the leading force in American psychology § -In contrast to Freudian Psychology/Psychiatry Other Well known American Behaviorists: Clark Hull (Yale) B. F Skinner (Harvard) Wrote novel Walden Two in 1948 and Beyond Freedom & Dignity in 9 1971
IVAN PAVLOV M. D. Lectures on Conditioned Reflexes: 25 Years of Objective Study of the Higher Nervous Activity (Behavior) of Animals A collection of lectures by Pavlov at Military Medical Academy in St. Petersburg in 1924 § English translation in 1927 or 1928 by his student from USA, W. Horsley Gantt (Johns Hopkins) § Summarized 25 years of research in great detail § Regretted the brain had become domain of psychology and not physiology § Paid tribute to: § § Rene Descartes-Described animals as machines who reacted predictably to stimuli presented to the nervous system Ivan Sechenov-Wrote “Brain Reflexes” (right) 10
IVAN PAVLOV M. D. Cortex as a switchboard of cells IMPLICATION for humans Responsible for different reflexes We can change behavior patterns and are susceptible to conditioning § More reflexes could be created § Existing ones could be altered Have the ability to break our own patterns if they ultimately prove not to be in our interests. 11
IVAN PAVLOV M. D. Other Concepts from Conditioned Reflexes Research § § § Timing-Timing of Stimuli is critical Extinction-CS repeatedly presented with out food: salivary response weakens Generalization-Stimuli different from initializing one-salivate less strongly Differentiation-Conditioned to two stimuli; if one stimuli led to food another did not, lose response to one Experimental Neurosis-After typical training, then unsuspected and chaotic stimuli produced “nervous breakdown” and after a long rest could recover but could never tolerate experiments as well as initially Questioned early signs of PTSD 12
IVAN PAVLOV M. D. Aristotle of Russia “Dynamic, Brilliant, Zealous Scientist” per his student and translator Gantt. Said his genius was based on : § Ability to design an experiment so as to eliminate extraneous factors (extreme skill at operating table) § Keen powers of observation § Use of imagination in developing concepts By nature, simple in his tastes and home life. Vehement in his likes and dislikes Fearlessly honest Ferocious in defending principles Exact Habits: Lunch at noon; played same records, on same night each week, each month; Sleep at exact same time Summer vacation in Estonia estate, same days each year, played strenuous games and read French novels Yerkes “to meet him was like meeting a fresh breeze from the sea” 13
IVAN PAVLOV M. D. Advice to Students in a Soviet Youth Group “First of all be systematic… Learn to do drudgery… Second…comes obesity; pride will deprive you of ability to be objective The third thing necessary is passion…be passionate in your work and in your search for truth” 14
IVAN PAVLOV M. D. Politics Benefited from Czar’s liberal education/ scholarship programs Critical of communism but survived and thrived in USSR Was a Czarist Lenin handed down decree that Laboratory was supported by Pavlov’s work was of Russian nobility “enormous significance to the Middle/”favorite” son Viktor was working classes of the whole killed in White Russian Army world” Pavlov at the XVth International Physiological Congress in Leningrad, 1935. Pavlov acknowledged his “I am not a Bolshevik and do gratitude to Soviet government not support the policies but we for its sponsorship of science must help the Bolsheviks in everything good about them. ” With the fall of the USSR, Pavlov then considered a champion of democracy and “the first dissident” 15
IVAN PAVLOV M. D. His Dogs While he experimented on dogs, he took great care of them and loved them. He did not destroy them. Considered them man’s best friend and science martyrs He erected a stone dog statue in the courtyard of the Institute of Experimental Medicine (below) 16
Pavlov’s Dogs 17
IVAN PAVLOV M. D. Late Life Research into Psychiatry At age 80 he began to study psychiatry Applied his physiologic studies in dogs to psychiatry and humans 1941 book (translated in English by Gantt): Conditioned Reflex and Psychiatry G. Sutherland called this the greatest book on psychiatry ever written! § From 1931 to 1936: § Pavlov Wednesdays- Would alternate dog research days one day a week § Pavlov Clinical Wednesdays. Observing psychiatric patients under supervision of a psychiatrist one day a week He did try to draw connections between abnormal behavior in dogs and humans 18
IVAN PAVLOV M. D. Anti-Semitism § Attributed negative dimensions of Bolshevism to Jewish influence § 1928 he complained to Gantt that the Jews occupied “high position everywhere” and that it was “a shame Russians can not be rulers of their own land” § 1935/1936 when he expressed a more positive attitude towards Bolsheviks he minimized the Jewish presence in the communist party as a “thin stratum” § 1934/1935 even Pavlov was scolding the Jews and on learning one woman among his listeners was Jewish he said : “Why didn’t anyone warn me? ” Lina Stern and Ivan Pavlov among the delegates of XIV 19 International Congress of Physiology, Rome 1932
IVAN PAVLOV M. D. Reference in Norman Mailer’s novel “The Naked and the Dead” 1948 Page 18: A psychologist in a famous experiment rang a bell every time he gave food to a dog. Naturally, the dog’s saliva flowed at the sigh of the food. After a time the psychologist took away the food, but continued to ring the bell. The dog kept on salivating to the sound of it. The psychologist went one step further: he took away the bell and substituted many INDs of loud noises. The saliva continued to form in the dog’s mouth. There was a soldier on the ship who was like the dog. He had been overseas for a long time, and he had seen a great deal of combat. At first the sound of the shell and the impact it made were very much connected to the fear he felt. But after many months, he had known too much terror, and by now any sudden sound would cause him panic. All this night he had been lying in his bunk and shuddering at the sound of quick loud voices, or at a change in the throbbing of the ship’s engines, or at the noise of a piece of equipment when someone kicked it along the floor. His nerves were pitched tauter that he could ever remember, and he lay sweating in his bunk, thinking with dread of the morning to come. The soldier's name was Sergeant Julio Martinez and he was the scout of the I and R platoon of headquarters company of the 460 th Infantry Regiment. 20
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