From phantom limbs and sick brains, through mirror neurons, synaesthesia, metaphor and abstract art, the ability of Vilayanur S. Ramachandran to generate new ideas about the human brain has made him a superstar. Just talking to him, I found out, puts your brain through a strenuous workout
"HE knows his leg belongs to him, he's not crazy. He just doesn't want it anymore," says Vilayanur Ramachandran. He calls this odd state of affairs "spooky". Downright terrifying seems more like it. Another of his patients believes he is, rather inconveniently, dead. "He says he can smell decaying flesh but doesn't bother committing suicide because what's the point? In his mind he's already dead."
Ramachandran is regaling me with these disturbing anecdotes at a recent Society for Neuroscience conference in San Diego, California. As one of the most prolific neuroscientists of our time, everyone wants a piece of him. I sneak a glance at the other reporters looking on as I whisk him out of the press room. He seems endearingly unaware of his popularity, shaking hands with "fans" at every turn. Then again, investigating strange neurological conditions and asking what they can tell us about the human mind has allowed him to develop special insights into the qualities of human uniqueness, something he is eager to share not only with his peers at the conference but with a wider audience through his books and lectures.
In person, Ramachandran sparkles, his hands shake with a slight, odd, quiver, but his smile suggests he is on the verge of either telling you something very wise - or very silly. But today there is no silliness: we talk about the complex topic of metaphor. He describes his theory that several areas of the brain developed in tandem which ultimately resulted in the uniquely human ability to link dissimilar concepts. "People don't like saying we're special because it smacks of creationism, but there are areas of the brain that, when developing, simultaneous and fortuitously combined to create something wonderful - this huge explosion of abilities that characterise the human brain."
Ramachandran is particularly interested in metaphor because it ties in neatly with his previous work on synaesthesia - a kind of sensory hijack, where, for example, people see numbers as colours or taste words. "Metaphor is our ability to link seemingly unrelated ideas, just like synaesthesia links the senses," he says. After spending years working with people who have synaesthesia, he believes "pruning genes" are responsible. In the fetal brain, all parts of the brain are interconnected, but as we age, the connections are pruned. If the pruning genes get it wrong, the connections are off. "If you think of ideas as being enshrined in neural populations in the brain, if you get greater cross-connectivity you're going to create a propensity towards metaphorical thinking," he says.
I don't have synaesthesia, neither does Ramachandran, but he points out to me the strangeness of asking why, say, the cheddar cheese in your sandwich is "sharp". It's true, cheese isn't sharp, it's soft, so why do I use a tactile adjective to describe a gustatory sensation? "It means our brains are already replete with synaesthetic metaphors," he says. "Your loud shirt isn't making any noise, it's because the same genes that can predispose you to synaesthesia also predispose you to make links between seemingly unrelated ideas, which is the basis of creativity."
This ability to link ideas allowed us to swing through the trees, he explains. "Making the connection between the angle of a branch and the angle of your hand is a form of abstraction. Once this fundamental ability to abstract was in place we could start to do more complicated abstractions," he says. "If a cat sees a rat, it's just a long thing that's good to eat. For you, a rat evokes associations with the plague. And for me, that quality is unique to humans."
It's not just words that get him going these days, but drawings, too. Ramachandran came to art after hearing a lecture on Auguste Rodin - and it's now both a hobby and a fundamental part of his work. As if to prove it, he grabs a notepad and draws a picture. It bears a pretty good likeness to a seagull. "This is brilliant," he grins, not boasting about his artistic abilities but preparing me for his next tale.
"A newborn gull chick begs for food from its mother by pecking at a red spot on its mother's beak," he explains. "The mother then regurgitates food into the chick's mouth. You can just hold a beak without the mother and the chick will still peck at it. But here's the best part," he says, gearing up for the denouement like a motorised bunny. "Put three red stripes onto a stick and the chick goes crazy, completely berserk, and totally ignores the real beak."
At this point, he sounds passionate: "Maybe the neurons responsible have a rule that the more red the better, so by putting three stripes on it you're stimulating these neurons more optimally and this sends a jolt to the limbic system which says 'wow what a sexy beak!' "
But how does this relate to art, I ask. "It's what a great abstract artist has discovered by intuition, genius or accident - a Picasso is merely a stick with three stripes for the human brain!"
Ramachandran was just about to give me the intriguing neurological explanation for why people prefer to glimpse a nude behind a shower curtain rather than full frontal in a magazine when his phone beeps and our interview is briefly put on hold.
As I wait, I remember reading that Ramachandran could never remember his children's or his wife's birthdays. "It doesn't mean I don't love you," he had told them. After listening to his voicemail, he says, sheepishly: "I forgot to turn up to another interview." It's funny and intriguing that the man with such a privileged insight into the brain is himself so often absent-minded. "Where were we?" he asks.
But it doesn't seem to matter. Despite his forgetfulness, Ramachandran speeds from one fascinating topic to the next, with an excitement that's somewhere between a young researcher on the verge of a great discovery and a small child on a sugar rush.
Eventually he returns, as I knew he would at some point, to his pet subject: mirror neurons. These neurons are thought to act in the same way when you perform an action or watch someone else performing the same action, giving a rich internal reflection of their actions. For Ramachandran, this system is likely to have played a key role in making us unique. "It probably developed from being able to understand another's actions and then turned in on itself. Suddenly you're taking an allocentric rather than egocentric view of yourself. That's the dawn of self-awareness."
And it's impossible to curb his enthusiasm. "Mirror neurons make us all alike, they're acting in the same way whether you or I make the action. If you remove my skin, I dissolve into you," he explains. It's a fascinating concept and the mainstay of many eastern religious traditions. But he's a little guarded when I ask whether he is religious, claiming no obvious alliance to any particular religion nor atheism, but accepting that what he has just said gives some credence to talk of us all being interconnected - as long as you don't take it too literally. "There's no real difference between you and other people," he says. "Through our mirror neurons we're all hooked up together."
That's why interviewing Ramachandran is such a treat: you turn up expecting to find out more about him, and in some spooky mixing of minds end up finding out a whole lot more about yourself.