Vilayanur Subramanian Ramachandran (born August 10, 1951) is a neuroscientist known primarily for his work in the fields of behavioral neurology and visual psychophysics. He is currently a Professor in the Department of Psychology and the Graduate Program in Neurosciences at the University of California, San Diego.
Ramachandran is an exceptionally well known scientist. He is the author of several books that have garnered widespread public interest. These include Phantoms in the Brain (1998), "A Brief Tour of Human Consciousness" (2004) and The Tell-Tale Brain (2010). He has been profiled in the New Yorker and the Indian Swarajya Magazine. Ramachandran has been called "The Marco Polo of neuroscience" by Richard Dawkins and "the modern Paul Broca" by Eric Kandel. In 1997, Newsweek named him as a member of the "Century Club" one of the most prominent people to watch in the next century. In 2008, he was listed as number 50 in the Top 100 Public Intellectuals Poll. In 2011, Time listed him as one of "the most influential people in the world" on the "Time 100 list".
Video Vilayanur S. Ramachandran
Early life and education
Vilayanur Subramanian Ramachandran (in accordance with some Tamil family name traditions, the town of his family's origin, Vilayanur, is placed first) was born in 1951 in Tamil Nadu, India. His father, V.M. Subramanian, was an engineer who worked for the U.N. Industrial Development Organization and served as a diplomat in Bangkok, Thailand. Ramachandran attended schools in Madras, and British schools in Bangkok. Ramachandran obtained an M.B.B.S. from the University of Madras in Chennai, India, and subsequently obtained a Ph.D. from Trinity College at the University of Cambridge. He then spent two years at Caltech, as a research fellow working with Jack Pettigrew. He was appointed Assistant Professor of Psychology at the University of California, San Diego in 1983, and has been a full professor there since 1998.
Maps Vilayanur S. Ramachandran
Scientific career
Ramachandran's early research was on human visual perception using psychophysical methods to draw clear inferences about the brain mechanisms underlying visual processing. In the early 1990s Ramachandran began to focus on neurological syndromes such as phantom limbs, body integrity identity disorder and the Capgras delusion. He has also contributed to the understanding of synesthesia and is known for inventing the mirror box. Ramachandran is noted for his use of experimental methods that make relatively little use of complex technologies such as neuroimaging. Despite the apparent simplicity of his approach, he has generated many new ideas about the brain.
Ramachandran is the director of a research group at the University of California, San Diego, known as the Center for Brain and Cognition. This group, made up of students and researchers from different universities, is affiliated with the Department of Psychology at UCSD. Members of the CBC have published articles on a range of emerging theories related to neuroscience.
In 2012 Laura Case and Ramachancran published a theory about the possible role of brain plasticity in bigender alternation. In 2017 Baland Jalal and Ramachandran published an article in which they speculated about the role of mirror neurons in the experience of the bedroom intruder during sleep paralysis.
Theories and research
Phantom limbs
When an arm or leg is amputated, patients often continue to feel vividly the presence of the missing limb as a "phantom limb" (an average of 80%). Building on earlier work by Ronald Melzack (McGill University) and Timothy Pons (NIMH), Ramachandran theorized that there was a link between the phenomenon of phantom limbs and neural plasticity in the adult human brain. In particular, he theorized that the body image maps in the somatosensory cortex are re-mapped after the amputation of a limb. In 1993, working with T.T. Yang who was conducting MEG research at the Scripps Research Institute, Ramachandran demonstrated that there had been measurable changes in the somatosensory cortex of a patient who had undergone an arm amputation. Ramachandran theorized that there was a relationship between the cortical reorganization evident in the MEG image and the referred sensations he had observed in other subjects. Ramachandran believed that the non-painful referred sensations he observed were the "perceptual correlates" of cortical reorganization; however research by neuroscientists in Europe demonstrated that the cortical reorganization seen in MEG images was related to pain rather than non-painful referred sensations. The question of which neural processes are related to non-painful referred sensations remains unresolved.
Mirror visual feedback
Ramachandran is credited with the invention of the mirror box and the introduction of mirror visual feedback (mirror therapy) as a treatment for phantom limb paralysis. Ramachandran found that in some cases restoring movement to a paralyzed phantom limb reduced pain as well.
Research on the use of mirror therapy in reducing pain has not provided consistent outcomes. Systematic reviews of the research literature have arrived at conflicting conclusions about the effectiveness of MT. A 2014 review found that MVF can exert a strong influence on the motor network, mainly through increased cognitive penetration in action control. However, a 2016 review concluded that the level of evidence is insufficient to recommend MT as a first intention treatment for phantom limb pain. The effectiveness of mirror therapy continues to be evaluated.
Neural cross-wiring: synesthesia and metaphors
Ramachandran has theorized that synesthesia arises from a cross-activation between brain regions. One common form is called Grapheme-color synesthesia, where certain letters appear to be colored, or tinted. Ramachandran and his graduate student, Ed Hubbard, conducted research with functional magnetic resonance imaging that found increased activity in the color recognition areas of the brain in synesthetes compared to non-synesthetes.
Ramachandran has speculated that synesthesia and conceptual metaphors may share a common basis in cortical cross-activation. In 2003 Ramachandran and Edward Hubbard published a paper in which they speculated that the angular gyrus is at least partially responsible for understanding metaphors.
The neurological basis of synesthesia is not clearly understood; in 2015 an extensive review of synesthesia research concluded that the neurological correlates of synesthesia have not been established.
Mirror neurons
Ramachandran is known for advocating the importance of mirror neurons. Ramachandran has stated that the discovery of mirror neurons is the most important unreported story of the last decade. (Mirror neurons were first reported in a paper published in 1992 by a team of researchers led by Giacomo Rizzolatti at the University of Parma.) In 2000, Ramachandran made a prediction that "mirror neurons will do for psychology what DNA did for biology: they will provide a unifying framework and help explain a host of mental abilities that have hitherto remained mysterious and inaccessible to experiments."
Ramachandran has speculated that research into the role of mirror neurons will help explain a variety of human mental capacities such as empathy, imitation learning, and the evolution of language. Ramachandran has also theorized that mirror neurons may be the key to understanding the neurological basis of human self-awareness. At this point, there is no scientific consensus about the role played by mirror neurons in humans.
"Broken Mirrors" theory of autism
In 1999, Ramachandran, in collaboration with then post-doctoral fellow Eric Altschuler and colleague Jaime Pineda, hypothesized that a loss of mirror neurons might be the key deficit that explains many of the symptoms and signs of autism spectrum disorders. Between 2000 and 2006 Ramachandran and his colleagues at UC San Diego published a number of articles in support of this theory, which became known as the "Broken Mirrors" theory of autism. Ramachandran and his colleagues did not measure mirror neuron activity directly; rather they demonstrated that children with ASD showed abnormal EEG responses (known as Mu wave suppression) when they observed the activities of other people. Ramachandran's "broken mirror hypothesis" explanation for autism remains controversial.
Rare neurological syndromes
Capgras delusion
In collaboration with William Hirstein, Ramachandran published a paper in 1997 in which he presented a theory regarding the neural basis of Capgras delusion, a delusion in which family members and other loved ones are thought to be replaced by impostors. Prior to Ramachandran's 1997 paper, psychologists HD Ellis and Andy Young had theorized that Capgras delusion was created by a neurological disconnection between facial recognition and emotional arousal. Based on the evaluation of a single subject, who did not manifest complex psychological symptoms, Ramachandran and Hirstein hypothesized that Capgras delusion involves memory management problems, in addition to a disconnection between facial recognition and emotional arousal. According to their theory, a person suffering from Capgras delusion loses the ability to manage memories effectively.
Xenomelia (Apotemnophilia)
In 2008, Ramachandran, along with David Brang and Paul McGeoch, published the first paper to theorize that apotemnophilia is a neurological disorder caused by damage to the right parietal lobe of the brain. This rare disorder, in which a person desires the amputation of a limb, was first identified by John Money in 1977. Building on medical case studies that linked brain damage to syndromes such as somatoparaphrenia (lack of limb ownership) the authors speculated that the desire for amputation could be related to changes in the right parietal lobe. In 2011 McGeoch, Brang and Ramachandran reported a functional imaging experiment involving four subjects who desired lower limb amputations. MEG scans demonstrated that their right superior parietal lobules were significantly less active in response to tactile stimulation of a limb that the subjects wished to have amputated, as compared to age/sex matched controls. They suggested that xenomelia is best viewed as a developmental disorder of the right parietal lobe function. The authors introduced the word "Xenomelia" to describe this syndrome, which is derived from the Greek for "foreign" and "limb".
Neural basis of religious experience
In a 1997 Society for Neuroscience talk, Ramachandran hypothesized that there may be a neural basis for some religious experiences. He stated that "There may be dedicated neural machinery in the temporal lobes concerned with religion. This may have evolved to impose order and stability on society." Ramachandran described an experiment in which he measured the galvanic skin responses of two subjects who had experienced temporal lobe seizures. Ramachandran measured the subjects' responses to a mixture of religious, sexual and neutral words and images and found that religious words and images elicited an unusually high response. Ramachandran has also discussed his ideas about the neural basis of religion in a number of talks and in Phantoms In The Brain. He cautions that his ideas are tentative, and so far he has not published any research on this subject.
Awards and honors
Ramachandran was elected to a visiting fellowship at All Souls College, Oxford (1998-1999). In addition, he was a Hilgard visiting professor at Stanford University in 2005. He has received honorary doctorates from Connecticut College (2001) and the Indian Institute of Technology, Madras (2004). Ramachandran received the annual Ramon y Cajal award (2004) from the International Neuropsychiatric Society, and the Ariëns Kappers Medal from the Royal Netherlands Academy of Sciences for his contributions to Neuroscience (1999). He shared the 2005 Henry Dale Prize with Michael Brady of Oxford, and, as part of the award was elected an honorary life member of the Royal institution for "outstanding research of an interdisciplinary nature". In 2007, the President of India conferred on him the third highest civilian award and honorific title in India, the Padma Bhushan.
- Phantoms in the Brain: Probing the Mysteries of the Human Mind, coauthor Sandra Blakeslee, 1998 (ISBN 0-688-17217-2).
- The Encyclopedia of the Human Brain (editor-in-chief) (ISBN 0-12-227210-2).
- The Emerging Mind, 2003 (ISBN 1-86197-303-9).
- A Brief Tour of Human Consciousness: From Impostor Poodles to Purple Numbers, 2005 (ISBN 0-13-187278-8; paperback edition).
- The Tell-Tale Brain: A Neuroscientist's Quest for What Makes Us Human, 2010 (ISBN 978-0-393-07782-7).
See also
- Body image
- Lisa M. Montgomery (Ramachandran's testimony as an expert witness)
- Oliver Sacks
- Sound symbolism (phonaesthesia)
- Temporal lobe epilepsy
References
External links
- Vilayanur S. Ramachandran (official webpage)
- Take the Neuron Express for a Brief Tour of Consciousness (The Science Network interview).
- Ramachandran Illusions
- All in the Mind interview
- Reith Lectures 2003 The Emerging Mind
- TED talk by Ramachandran on brain damage and mental structures.
- Talk at Princeton about his work (2009).
- The Third Culture, including three essays regarding mirror neurons and self-awareness.
- Ramachandran's contribution to The Science Network's Beyond Belief 2007 Lectures on synaesthesia and metaphor.
- Neuroscience in the 20th Century, 24 December 1998, BBC Radio program In Our Time
Source of article : Wikipedia
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