From The New York Times:
The men of old, reported Socrates, saw madness as a gift that provides knowledge or inspiration. “It was when they were mad that the prophetess at Delphi and the priestesses at Dodona achieved so much; . . . when sane they did little or nothing.” Today, insanity can still bring the gift of knowledge, but in a different manner. Much of what we know about the brain comes from seeing what happens when it is damaged, or affected in unusual ways. If the Delphic seer were to turn up tomorrow, neuroscientists would whisk her straight off into a brain scanner.
V. S. Ramachandran, a professor of neuroscience and psychology at the University of California, San Diego, has done as much as anyone to reveal the workings of the mind through the malfunctions of the brain. We meet some mighty strange malfunctions in his new book, “The Tell-Tale Brain: A Neuroscientist’s Quest for What Makes Us Human.” There is a man who, after a head injury, cannot recognize or respond to people when he sees them, but can happily chat on the phone. We meet a woman who laughs when she should be yelping in pain. There are patients with Capgras syndrome, who come to believe that people who are close to them (or, in one case, the patient’s poodle) are imposters. We meet unfortunates with an intense desire to have their own healthy limbs amputated, others who are paralyzed on one side but insist against all evidence that they are not, and, in Cotard’s syndrome, people who sincerely believe they are dead. Ramachandran weaves such tales together to build a picture of the specialized areas of the brain and the pathways between them, drawing his map by relating particular types of damage to their corresponding mental deficits.