Scientists have learned a good deal about brain trauma and the laws of mental life since the advent of computer-imaging in the early 1990s.

(The left hand may close a drawer as soon as the right hand has opened it, or undo buttons that have just been done up.) The hand seems to have a 'mind of its own'. In addition to quirks of speech, he looks at such disorders as alien-hand syndrome, where the actions of one hand appear to act independently of the patient's will.

Rather than dismiss such neural dysfunctions, Ramachandran believes they provide valuable insight into how the human brain functions. A patient of his in San Francisco started to create hauntingly lovely paintings post-surgery another began to speak in disjointed if poetic metaphors. Ramchandran's latest book amplifies on Nelson's phantom limb, and asks if brain damage can unleash a latent gift for language or art. In scientific terms, the sea lord's neural connections were trying to make sense of the pain of the amputation, but the wiring had gone awry. After the loss of his right arm in 1797 Lord Nelson felt non-existent fingers digging into his non-existent palm. Phantoms in the Brain, his 1998 bestseller, offered an Oliver Sacks-like inquiry into the bizarre ways in which the brain 'remaps' itself following trauma. VS Ramachandran, a neuroscientist based in California, writes engagingly on the fevers, frets and disorders that afflict our most precious and elusive organ. The change happened more or less overnight. Prior to the injury I had been taking lessons, but that hardly accounted for my sudden facility in a language I had spoken poorly. The accident left me with no permanent side-effects apart from one: my Italian became unaccountably fluent. Professore Milza (Prof Spleen) who performed the operation told me: 'You are missing some bone and therefore less thick-skulled than before.' He suggested a silver plate to protect my neural hardware but, for fear of picking up radio signals, I opted for an acrylic one. Surgery for the resultant haematoma – a swelling composed of blood effused into the connective tissues of the brain – left me with a cranial cavity the size of a healthy tangerine. Later, Calvino told me he heard ' un tonfo' (a thud) before the line went dead. I had been on the phone to the Italian novelist Italo Calvino, whom I hoped to interview. In Hitchcock manner the phone was dangling off the hook handprints of blood covered the walls where I had tried to steady myself. 'I'm afraid you've had an emergency brain operation.' A blurred but familiar face came into focus as the English girl who shared my flat she had found me on the floor with my breathing irregular and speech garbled (in neurological terms, 'aphasic'). I n 1984, after an unexplained fall, I woke up in a hospital in Rome acutely head-injured and disoriented.

The tell tale brain book