Roger Sperry and the Age of the Brain
Download as PPT, PDF3 likes6,677 views
The document discusses the contributions of Roger Sperry to neuroscience, particularly his work on split-brain theory and its implications for understanding consciousness. It outlines the historical context of neuroscience, significant milestones in the field, and Sperry's views on the relationship between brain activity and consciousness. The document also addresses the societal implications of left and right brain dominance and the interplay between scientific and humanist perspectives on consciousness and morality.
Roger Sperry and the Age of the Brain
- 1. 1913-1994
- 2. Roger Sperry and the Age of the Brain piero scaruffi www.scaruffi.com Univ of San Francisco, January 2013
- 3. Piero Scaruffi • Cultural Historian • Cognitive Scientist A Visual History of the Visual Arts (2012) A History of Silicon Valley (2011) • Poet Synthesis: Poems and Meditations (2010) A History of Rock and Dance Music (2009) • www.scaruffi.com A History of Jazz Music (2007) The Nature of Consciousness (2006) www.scaruffi.com 3
- 4. Cultural Context • The 1910s set the stage for a confrontation between the extremely rational and the extremely irrational EINSTEIN DADA RUSSELL JAZZ KAFKA www.scaruffi.com 4
- 5. Cultural Context/Sciences • The programmable computer (Konrad Zuse, 1941) • The mind is a symbol processor (Kenneth Craik, 1943) • Cybernetics: living beings are machines (Norman Wiener, 1947) • Information Theory: everything is information (Claude Shannon, 1948) • Machines with common sense (John McCarthy, 1949) • The Turing Test (Alan Turing, 1950) www.scaruffi.com 5
- 6. Cultural Context/Politics • World War II • Cold War (USA vs Soviet Union) • Decolonization • Civil-rights movements (Simone de Beauvoir ‘49, Harry Hay ‘50, ML King ‘55) • Population boom • Environmentalism (Rachel Carson 1962) www.scaruffi.com 6
- 7. A brief History of Neuroscience • 1771: Luigi Galvani discovers that nerve cells are conductors of electricity • 1796: Franz Joseph Gall’s phrenology (mental faculties are localized in specific brain regions) • 1836: Marc Dax notes that aphasic patients (incapable of speaking) have sustained damage to the left side of the brain • 1864: Paul Broca determines that the location of speech is in the left hemisphere • 1874: Karl Wernicke determines that loss of linguistic skills is related to damage to the left hemisphere • 1876: John Hughlings Jackson discovers that loss of spatial skills is related to damage to the right hemisphere www.scaruffi.com 7
- 8. A brief History of Neuroscience • "The Strange Case of Dr Jekyll and Mr Hyde" (1886) by Robert-Louis Stevenson “Frankenstein” (1818) by Mary Shelley www.scaruffi.com 8
- 9. A brief History of Neuroscience • 1891: Santiago Ramon y Cajal discovers the neuron, the elementary unit of processing in the brain • 1911: Edward Thorndike’s connectionism: the mind is a network of connections and learning occurs when elements are connected • 1921: Otto Loewi discovers the first neurotransmitter • 1940: Willian Van Wagenen performs “split brain” surgery to control epileptic seizures • 1949: Donald Hebb’s cell assemblies: the brain organizes itself into regions of self-reinforcing neurons - the strength of a connection depends on how often it is used • 1952: Paul Maclean discovers the "limbic system" • 1957: Vernon Mountcastle discovers the modular organization of the brain in vertical columns www.scaruffi.com 9
- 10. Roger Sperry • 1941: Ph.D. in Zoology from the University of Chicago • 1942: Postdoctoral work with Karl Lashley at Harvard • 1946: Department of Anatomy at the University of Chicago • 1947: Discovery of vertically oriented cortical columns (predating Mountcastle) • 1951: Chemoaffinity theory • 1953: Split-brain experiment on cats • 1954: Psychobiology at the California Institute of Technology • 1962: Study of "split brains" on humans • 1964: “Brain bisection and mechanisms of consciousness” • 1965: “Mind, Brain and Humanist Values” www.scaruffi.com 10
- 11. The Split Brain: A Tale of Two Halves • Roger Sperry at CalTech (1960s) www.scaruffi.com 11 William van Wagenen
- 12. The Split Brain: A Tale of Two Halves • Splitting of the corpus callosum of animals left them relatively normal. • The corpus callosum enables communication between the two hemispheres • Without it, each hemispheres is unaware of any experience of the other one www.scaruffi.com 12
- 13. The Split Brain: A Tale of Two Halves • Brain lateralization in humans • Left hemisphere: abstraction, reading, writing, speaking, arithmetic, reasoning and understanding (the “major” hemisphere) • Right brain: creative, communication, social skills but mostly a mystery CHECK YOUR IQ: Why do we know so much about the left hemisphere and so little about the right one? www.scaruffi.com 13
- 14. The Split Brain: A Tale of Two Halves • Brain lateralization www.scaruffi.com 14
- 15. The Split Brain: A Tale of Two Halves • “The great pleasure and feeling in my right brain is more than my left brain can find the words to tell you.” - Roger Sperry www.scaruffi.com 15
- 16. The Split Brain: A Tale of Two Halves • The myth – Left-brain dominant life: analytical, linear – Right-brain dominant life: creative but poor at math www.scaruffi.com 16
- 17. Split-brain Consciousness A Tale of Two Minds • Left-talking hemisphere responds “normally” • Right hemisphere reacts to stimula and reveals its own "mind" • They are unaware of each other LeDoux & Gazzaniga: • Different kinds of consciousness? “Integrated Mind” • Two conscious beings in the same body? (1977) Sperry’s "Brain Bisection and Michael Gazzaniga: "Consciousness Mechanisms of Consciousness" in & the Cerebral Hemispheres" “Brain And Conscious http://www.youtube.com/watch? Experience” - Study Week Sep 28 v=sSWK_JGu23E - Oct 4, 1964 of the Pontificia Academia Scientiarum www.scaruffi.com 17
- 18. Split-brain Consciousness A Tale of Two Minds • Why do we need two dinstinct “I”s instead of just one? + = www.scaruffi.com 18
- 19. Split-brain Consciousness A Tale of Two Minds • By cutting the corpus callosum are we turning one person into two people? www.scaruffi.com 19
- 20. A Tale of Multiple Minds • A body can even have four brains… www.scaruffi.com 20
- 21. The Century of the Brain • “All that is psychological is first physiological” (Sperry) www.scaruffi.com 21
- 22. The Century of the Brain • 1964: Paul Maclean’s triune brain: three layers, each layer corresponding to a different stage of evolution • 1964: John Young proposes a "selectionist" theory of the brain (learning is the result of the elimination of neural connections) • 1968: Niels Jerne’s selectionist model of the brain (mental life a continuous process of environmental selection of concepts in our brain - the environment selects our thoughts) • 1970s: Gerald Edelman’s "Neural Darwinism“ www.scaruffi.com 22
- 23. The Century of the Brain • 1985: Michael Gazzaniga’s “interpreter” (a module in the left brain interprets the actions of the other modules and provides explanations for our behavior) • 1989: Christof Koch discovers that at, any given moment, very large number of neurons oscillate in synchrony and one pattern is amplified into a dominant 40 Hz oscillation • 1996: Giacomo Rizzolatti discovers "mirror" neurons that represent what others are doing • 1996: Rodolfo Llinas: Neurons are always active and produce a repertory of possible actions, and the circumstances “select” which action is enacted www.scaruffi.com 23
- 24. And the meaning is… www.scaruffi.com 24
- 25. The Century of the Brain • 1956: Artificial Intelligence • 2002: Miguel Nicolelis makes a monkey's brain control a robot's arm via an implanted microchip • 2045: The Singularity www.scaruffi.com 25
- 26. Work in Progress • The origin of asymmetry – Human brains are asymmetric despite the fact that there is no physical difference between the two hemispheres – The human body is symmetric outside but asymmetric inside Chris McManus: – Engineers abhor asymmetry Right Hand, Left Hand The Origins of Asymmetry in Brains, Bodies, Atoms and Cultures Michael Levin: “The (2002) Embryonic Origins of Left-Right Asymmetry” (2004) www.scaruffi.com 26
- 27. Work in Progress • Sex and the brain – The right and left hemispheres of the brain are more asymmetrically organized for speech and spatial functions in men than in women – Speech disorders (aphasias) are caused by different kinds of damage in male and female brains – The emotion control center of the brain, the amygdala, behaves completely differently (e.g., higher levels of activation in males viewing sexual visual stimuli than females viewing the same images) – Female and male brains process colors in different ways – Significant differences in the inferior parietal lobule (IPL) of the neocortex (visual, auditory and somatosensory processing) – Etc etc www.scaruffi.com 27
- 28. The Split brain of 20th century Culture & Society • Left brain dominant (analytical) – Modernism: science, technology, economics, structuralism, sociology, marxism, psychoanalysis, computers • Right brain dominant (creative) – Antimodernism and Postmodernism: phenomenology, existentialism, gestalt psychology, dadaism, expressionism, surrealism, pop art, noise, rock & roll, bluis/soul/hip-hop www.scaruffi.com 28
- 29. The Split brain and Beauty • Beauty is a sophisticated interplay between symmetry and asymmetry Chitresh Das Company www.scaruffi.com 29
- 30. The other Sperry (1965) • “I have never been entirely satisfied with the materialistic or behavioristic thesis that a complete explanation of brain function is possible in purely objective terms with no reference whatever to subjective experience” (1959) • Where does behavior come from? • What is the purpose of consciousness? www.scaruffi.com 30
- 31. The other Sperry (1965) • “Prior to the advent of brain, there was no color and no sound in the universe, nor was there any flavor or aroma and probably rather little sense and no feeling or emotion” www.scaruffi.com 31
- 32. The other Sperry (1965) • Consciousness is not – an epiphenomenon – identical to neural activity • "Conscious phenomena are not reducible to neural events“ (Sperry, 1977) • Consciousness is an emergent phenomenon of neural activity (mentalist monism) • Consciousness determines brain processes • Gestalt psychology (the whole has a life of its own) but also reductionism (the part can explain the whole) • Mind can rule matter www.scaruffi.com 32
- 33. The other Sperry • Consciousness includes moral values (conscience) • Moral values determine brain processes • Brain activity is a goal-directed value-guided decision system www.scaruffi.com 33
- 34. The other Sperry www.scaruffi.com 34
- 35. The other Sperry • “Human values are inherently properties of brain activities” • Morality = an innate (genetic) system of values + a system of (cognitive) values shaped by brain activity • Hierarchy of values that shapes society www.scaruffi.com 35
- 36. The other Sperry • Human values are the main causes of human action • “Every voluntary act and/or decision by an individual or a group inevitably is governed, overtly or implicitly, by value priorities. In essence, what a person or society values determines what it does." www.scaruffi.com 36
- 37. The other Sperry • “Scientific theology”: an ethics based on science • Science should not only deal with “what is” but also with “what ought to be” www.scaruffi.com 37
- 38. The other Sperry • “Cognitivism bridges the chasm between what the writer C. P. Snow has called the "two cultures" -- the widening gap between the world view of the scientist and the humanist. The Caltech philosopher W. T. Jones has called this the crisis of contemporary culture. ” (1987) www.scaruffi.com 38
- 39. Individual brains, global brain • As far as we can tell, our brains are essentially like those of the first Homo Sapiens Sapiens of 200,000 years ago • Whatever change happened and is happening to the human race is not due to changes to the brain www.scaruffi.com 39
- 40. Intelligence and Brain Size • The biggest brain (about 10 kg) belongs to the sperm whale • The record for brain size compared with body mass belongs to the squirrel monkey (5% of the body weight, versus 2% for humans) • The sparrow is a close second to the squirrel monkey • Species that live in large social groups have the largest brains (e.g., the squirrel monkey) www.scaruffi.com 40
- 41. The End (for now) The longest living beings on this planet have no brain: trees and bacteria www.scaruffi.com 41
- 42. Body Stanford - Thursday January 17 Stanford Multidisciplinary Multimedia Meeting of Arts, Science and Humanities... SMMMASH! www.scaruffi.com 42