Everything about V S Ramachandran totally explained
Vilayanur S. "Rama" Ramachandran (born 1951) is a
neurologist best known for his work in the fields of
behavioral neurology and
psychophysics. He is currently the Director of the
Center for Brain and Cognition, Professor in the Psychology Department and Neurosciences Program at the
University of California, San Diego, and Adjunct Professor of Biology at the
Salk Institute for Biological Studies. Ramachandran initially obtained an
M.D. at
Stanley Medical College in
Madras, India, and subsequently obtained a Ph.D. from Trinity College at the University of Cambridge. Ramachandran’s early work was on visual perception but he's best known for his experiments in behavioral neurology which, despite their apparent simplicity, have had a profound impact on the way we think about the brain. He has been called “The
Marco Polo of neuroscience” by
Richard Dawkins and "the modern
Paul Broca" by
Eric Kandel.
Newsweek magazine named him a member of "The Century Club", one of the "hundred most prominent people to watch" in the 21st century. Ramachandran has been elected to fellowships at
All Souls College,
Oxford, and the
Royal Institution,
London (which also awarded him the Henry Dale Medal). He gave the 2003 BBC
Reith Lectures and was conferred the title of
Padma Bhushan by the President of India in 2007.
Early life and education
V.S. Ramachandran was born in
Tamil Nadu,
India to an Indian diplomat, and spent much of his youth abroad, at posts in Asia and India.
Ramachandran conjectured (and showed using
MEG) that when the arm is amputated the vacated
cortical territory corresponding to the missing arm is “invaded” by neurons which respond to stimulation of the face which normally would only go to the face region of the cortical homonculus. Signals from the face would then activate the original hand area of cortex and higher brain centers interpret this activation as arising from the phantom hand. The results show that brain maps are highly malleable; not fixed at birth as was previously believed.
Most patients with phantom arms feel that they can move their phantoms but in many the phantom is fixed or "paralyzed", often in a cramped position that's excruciatingly painful. Ramachandran suggested that this paralysis was due to the fact that every time the patient attempted to move the paralyzed limb, he or she received
sensory feedback (through
vision and
proprioception) that the limb didn't move. This feedback stamped itself into the brain circuitry through a process of
Hebbian learning, so that, even when the limb was no longer present, the brain had learned that the limb (and subsequent phantom) was paralyzed. In order to overcome this learned paralysis, Ramachandran created the
mirror box in which a mirror is placed vertically in front of the patient and had patients look at the mirror reflection of the normal arm so that the reflection was optically superimposed on the felt location of the phantom (thus creating the visual illusion that the phantom had been resurrected). Remarkably if the patient now moved his normal hand while looking at the reflection, he not only saw the phantom move (as expected) but felt it to move as well. In some patients this seemed to abolish the pain in the phantom. In others the phantom disappeared entirely – along with the pain – for the first time in years. The clinical usefulness of this mirror visual feedback (MVF) procedure has now been confirmed by several groups using double-blind placebo controlled trials. In the same series of studies, Ramachandran also found that merely creating the visual illusion of seeing the phantom being touched (using mirrors) sometimes evoked touch sensations in the phantom.
Ramachandran also used phantom limbs to explore the perceptual correlates of the
mirror neuron system in humans. Sensory neurons in the brain are activated in response to that person being touched, and a certain proportion of these same neurons also fire when someone watches another person, being touched (
mirror neurons) as if the neuron was “reading” the other persons mind or “empathizing”. But the person watching someone else being touched doesn't normally experience the touch delivered to the other person presumably because the skin on his own hand is sending a null signal (to the non-mirror neuron type sensory neurons) that vetoes the output of mirror neurons. Consistent with this theory, Ramachandran found that when a patient with a phantom arm watched another person’s intact hand being rubbed, he actually felt his phantom being rubbed. Massaging the other persons hand appeared to relieve the pain in the phantom, an observation that might have clinical implications if confirmed.
Stroke rehabilitation
In 1994 Ramachandran suggested that visual feedback may also help accelerate recovery of arm (and leg) function after paralysis from stroke. In 1998 Ramachandran (and his colleague Eric Altschuler) tested MVF on nine patients with stroke and observed striking recovery in many of them. This finding has also now been replicated in a number of groups including some who have used virtual reality instead of mirrors. More recently MVF has also been found to promote recovery from
complex regional pain syndrome (RSD).
Taken collectively, these results (together with the work of
Michael Merzenich,
Jon Kaas, Paul Bach-y-Rita, Alvaro Pascal-Leone, and others) have ushered in a new approach to brain function and neurological rehabilitation. The old picture of the brain as a set of autonomous modules hardwired at birth has been replaced with the view that the so-called brain modules are in a state of dynamic equilibrium with each other and with the sensory input. Many neurological disorders - but not all - may result from a shift in this equilibrium rather than permanent destruction of neural tissue. This isn't only of considerable theoretical interest but also clinically useful because it implies that relatively simple procedures may be enormously effective in rehabilitation of brain function.
Synesthesia
synesthesia, a condition in which viewing black and white letters or numbers on a page evokes the experience of seeing colors. Ramachandran (with then PhD student, Edward Hubbard) showed that some synesthetes (those who experience synesthesia) were better able to detect "embedded figures" composed of one letter or number (for example a triangle composed of 2s) on a background of another number (for example 5s). This is a difficult task for people who don't experience synesthesia. However, some synesthetes report that the colors they see help them to find and identify the embedded shape. Their performance on behavioral tasks show that some synesthetes are better at this task than non-synesthetes.
Based on his previous work on phantom limbs, Ramachandran suggested that synesthesia may arise from a similar cross-activation between brain regions. However, rather than being within a single sensory stream, this form of cross-activation would occur between sensory streams, and is thought to be due to genetic differences, rather than neural re-organization. In
fMRI experiments, increased activity in a color selective region (h
V4) was found in synesthetes compared to non-synesthetes when they viewed letters and numbers that evoked synesthetic colors, compared with symbols that did not.
Capgras delusion
In collaboration with then post-doctoral fellow,
William Hirstein, Ramachandran also explored the neural mechanisms behind
Capgras delusion, a delusion in which family members and other loved ones are thought to be replaced by impostors, which can occur after brain trauma. Based on the classical observations that Capgras usually occurs only for people that are close to the patient, and that the delusions tend to be absent if the person is only spoken to (for example, via telephone), Ramachandran and Hirstein suggested that Capgras might be a result of a disconnection between the "fusiform face area", a region of the
fusiform gyrus involved in
face perception, and the
amygdala which is involved in the emotional responses to familiar faces. Ramachandran and Hirstein hypothesized that because the neural machinery involved in recognizing faces is intact, the patient recognizes the person as looking like his or her loved one. However, since the connection between face recognition and the emotional centers in the amygdala are severed, the emotional response generated by the face is absent, leading to the delusion that the seen loved one must be an impostor. To test this theory, Ramachandran and Hirstein used the
galvanic skin response (GSR), which measures emotional arousal, to show that patients suffering from Capgras delusion didn't show the appropriate GSR to familiar faces. Subsequent work has expanded on these findings, and suggested that concurrent damage to other brain regions involved in reality monitoring must also occur.
Pathophysiology of autism
Ramachandran's group was the first to suggest and show experimentally in 1999, that a loss of
mirror neurons may be the key deficit in autism that explains many of the symptoms and signs of the disorder (collaborators included Ramachandran's students and colleagues: Lindsay Oberman, Eric Altschuler, and Jaime Pineda). These observations have now been confirmed by several groups.
Awards and honors
In 2005 Ramachandran was awarded the Henry Dale Medal and elected to an honorary life fellowship by the
Royal Institution of Great Britain. His other honors and awards include fellowships from
All Souls College,
Oxford, and the
Center for Advanced Study in the Behavioral Sciences at
Stanford University, the
Neurosciences Institute,
La Jolla, California and the
Athenaeum Club,
London. He has also received two honorary doctorates (DSc,
honoris causa), the annual
Ramon y Cajal award from the
International Neuropsychiatry Society, and the Ariens-Kappers medal from the
Royal Netherlands Academy of Sciences for Landmark contributions to Neuroscience. Most recently, in 2007, the President of India conferred on him the third highest civilian award and honorific title in India, the
Padma Bhushan.
Visiting professorships
Invited plenary lectures
Ramachandran has presented numerous plenary lectures around the world including at the inaugural conference of the Cognitive Neuroscience Society, the keynote to the inaugural annual Dementia Congress, the Alfred Deakin lectures to the government of Australia, the keynote Presidential lecture to the
American Academy of Neurology, the inaugural address of the University of Bristol’s new Neurosciences Department, and even the Getty Museum of Art. In 1995 he gave the
Decade of the Brain lecture at the 25th annual (Silver Jubilee) meeting of the
Society for Neuroscience. Separately, yet under the same title, he gave the
Decade of the brain lecture to the
National Institute of Mental Health and Library of Congress. Ramachandran has also delivered the Dorcas Cummings plenary lecture in Cold Spring Harbor, Fred Attneave memorial lecture to the University of Oregon, the Oliver-Sharpey lecture to the Royal College of Physicians in London, the Jonas Salk Memorial lecture at the Salk Institute, and the Rabindranath Tagore lecture at the Center for the foundations of science in New Delhi.
In 2003 he gave the annual BBC
Reith Lectures and was the first physician/psychologist to give the lectures since they were begun by
Bertrand Russell in 1949. More recently, he completed a public lecture to the Royal Society in London.
Genealogy
Ramachandran is the grandson of Sir
Alladi Krishnaswamy Iyer, Governor General of Madras and co-architect of the
Constitution of India.
Media coverage
Ramachandran's work in behavioral neurology has been widely reported by the
media. He has appeared in numerous
Channel 4 and
PBS documentaries. He has also been featured by the
BBC, the
Science Channel,
Newsweek, and
This American Life. He gave the
2003 Reith Lectures, entitled
The Emerging Mind, which were created in honor of
Lord Reith, the founder of the BBC.
Books by Ramachandran
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 Man with the Phantom Twin: Adventures in the Neuroscience of the Human Brain Due out June 2008. ISBN 978-0-525-95023-3Further Information
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