VS Ramachandran: The Marco Polo of neuroscience

Vilayanur Subramanian Ramachandran is not a name that rolls off the tongue, even in its more common abbreviated form of VS Ramachandran. Perhaps this is the reason its owner is not as well known by the general public as his fellow neurologist and friend Oliver Sacks. But within the sciences he is seen as one of the great pioneers of our time.

In an often-quoted description, Richard Dawkins once wrote: "Ramachandran is a latterday Marco Polo, journeying the Silk Road of science to strange and exotic Cathays of the mind." Such is his reputation for pushing back the boundaries of neuroscience that Newsweek magazine identified him among the "100 most prominent people to watch" in the 21st century.

The former Cambridge PhD student has also been feted in Britain, giving the Reith lectures in 2003, gaining fellowships of All Souls College and the Royal Institution, as well as a two-part Channel 4 series. Furthermore, his book Phantoms in the Brain was highly acclaimed. But for all that recognition, he's still not easily recognised. That may change with his latest book, The Tell-Tale Brain, which, according to the Financial Times, is an unimprovable "sweep of contemporary neuroscience".

And neuroscience is where the intellectual action is these days. In a recent edition of the New Yorker, the journalist David Brooks declared: "We are living in the middle of a revolution in consciousness… brain science helps fill the hole left by the atrophy of theology and philosophy."

If so, then no one has supplied more theories and findings to fill that hole than Ramachandran. The Cartesian division of mind and body long ago fell out of fashion in both philosophy and neuropsychology, but only recently have we begun to realise that not only is the brain part of the body but the body is also part of the brain. Ramachandran has been at the forefront of reimagining this interdependence with his ground-breaking work on phantom limbs.

Among amputees, 90% suffer from phantom limb pain, which can often cause excruciating discomfort. For most of the 20th century, medical science was divided over whether the cause was psychological or as a result of traumatised nerve endings. Neither hypothesis did much to help the afflicted.

In the mid-90s, Ramachandran approached the question from a more holistic perspective. The brain, we now know, contains a sensory map of the body and when the body fails to send sensory data that fits the map all manner of problems can occur. Ramachandran suspected that memories of the signals sent out by a limb before amputation remain locked in the central nervous system and the brain.

In an era of highly advanced and expensive brain scanning equipment, much of Ramachandran's work is characterised by a low-tech approach that he attributes to his Indian education. Thus, he devised a simple experiment with a mirror in which, through a visual trick, the amputee gained the impression that he was able to move his non-existent limb. His trial patient reported a shrinking of the phantom limb and diminution in pain. Ramachandran noted that it was "the first example in medical history of a successful 'amputation' of a phantom limb".

The result led Ramachandran to speculate on the wider sensory causes of a variety of mental conditions that had previously been ascribed to brain malfunction. He postulated that schizophrenics who hear voices may have suffered damage to a sensory mechanism in their vocal cords which signals to the brain, when healthy people think, to let it know that no one is actually saying the thought. If that mechanism is faulty, Ramachandran suggests, then an unconscious movement of the vocal cords might be perceived as an external voice speaking in the schizophrenic's head.

This kind of gadfly speculation, founded on a mixture of solid research, inspired intuition and a free-ranging imagination, has shaped Ramachandran's scientific outlook ever since he was a boy. He was born into a well-established Brahmin family in Tamil Nadu in India. His father was a UN diplomat and his grandfather a former attorney general of Madras who had helped draft the Indian constitution.

Like many children, when Ramachandran was a young boy, he collected seashells and fossils. Unlike most children, however, he sent his findings to the American Museum of Natural History, often unearthing rarities that were of interest to the museum. He retains an abiding love of palaeontology. Two years ago, he received his most enduring honour: a dinosaur – Minotaurasaurus ramachandrani – was named after him.

Although he was attracted to pure science, under his father's instruction, he studied medicine in Madras. It was there as a second-year student that he set up an experiment to examine how the brain merges the two slightly different images seen by each eye. He decided, as he precociously put it, that "concepts of retinal rivalry need drastic revision". He wrote a paper on his findings in 1971 and sent it to Nature, arguably the world's most prestigious scientific journal, and it was published unrevised.

Soon afterwards, he found himself at Trinity College, Cambridge, doing a PhD in visual perception. His fellow scientists turned out to be disappointments. "I thought they'd be like Faraday and the great Renaissance scientists," he later complained. However, he was galvanised by a visiting lecturer from Bristol University, the neuropsychologist Richard Gregory, whom he rates as "one of the five most amazing" people he's ever met.

They've since collaborated on a variety of disparate projects, including a study of how flounder fish change their body colouring to fit in with their background. That was also published in Nature, but this time the journal insisted on removing the co-writers' puns.

Ramachandran, who is 59, is known for what his critics see as sophomoric humour. In The Tell-Tale Brain, he recounts the neurological case of a man who saw a different woman each time he looked at his wife. "We should all be so lucky," quipped Ramachandran when speaking to the man's lawyer on the phone. The lawyer duly hung up. "My sense of humour is not always well received," he admits.

While grounded on the page, he, like Sacks, is easily lost in abstraction in life. He continually forgets where he has parked his car, for example, and can't remember his wife's birthday; they've been married for 24 years. His mind seems to be relentlessly engaged in much larger questions than the whereabouts of his car.

After the breakthrough with phantom limbs, Ramachandran did something that very few scientists attempt: he changed discipline, leaving visual perception for neurology. He is now professor in the psychology department and neurosciences programme at the University of California, San Diego.

The paradigm shift in neurology in recent years has been the adoption of a more flexible model of how the brain works. It used to be thought that there was a series of zones that governed separate hard-wired functions. But Ramachandran has helped revise that view. In the 90s, he conducted brain-imaging experiments that clearly demonstrated that damaged brains are able to transfer functions to healthy sections of the brain and, in so doing, reorganise the sensory map.

Neuroplasticity, as it's called, gives us a much more acute understanding of how the brain works, but it doesn't bring us a great deal closer to the ghost in the machine: consciousness. Many scientists believe the sensory map imprinted on the brain forms a rudimentary consciousness, and the next stage of development is "mirror neurons", which enable us to ape the actions of others.

These neurons were first discovered in monkeys in the 1990s and last year they were formally identified in humans. Ramachandran, the mirror therapist, was quick to reflect on their potential and he predicts that their discovery "will do for psychology what DNA did for biology".

What they appear to tell us is that humans are first and foremost mimics. We make ourselves up as we go along by improvising from what we see. This model also suggests the self is in dynamic interaction with otherness, both copying behaviour and projecting its emotions on to others, which is the basis for the vital human quality of empathy. (Ramachandran speculated in 2000 that autism was caused by deficient mirror neurons and medical research is now going in this direction.)

It's Ramachandran's contention that self-reflection was formed somewhere in this process of self-projection. The mirror-neuron system enables us to see another person's point of view, what's known as an allocentric view, as opposed to an egocentric one. Ramachandran suggests that "at some point in evolution, this system turned back and allowed you to create an allocentric view of yourself. This is, I claim, the dawn of self-awareness".

One day, we may recognise Ramachandran as the scientist who realised that in learning to think about others, humans learned to think for themselves. But before that we first need to learn to recognise his name.