We are barely beginning to address the fact that interactions among many non-contiguous brain regions probably yield highly complex biological states that are vastly more than the sum of its parts. -- Antonio Damasio
The human brain is the most astonishing and mysterious of all known complex systems. Inside this mass of billions of neurons, information flows in ways that we are only starting to understand. The memories of a summer day on the beach when we were kids; imagination; our dreams of impossible worlds. Consciousness. Our surprising capacity for mathematical generalization and understanding of deep, sometimes counterintuitive questions about the universe. Our brains are capable of this and much more. How? We don't know: the mind is a daunting problem for science.
When a brain fails, its failure can be as puzzling as normal function. Sometimes mental disorders are comical, as with poor Don Quixote, who, after many nights of no sleep and too much reading of old books, started to confuse reality with tales about dragons and chivalry (Figure 5.1). Sometimes the injured brain acts in ways that are simply bizarre. The essays of Oliver Sacks give us an impressive list of examples. 1 One of Sacks's patients was a musician and teacher who began to have problems recognizing the faces of his students. He could recognize, for example, familiar voices, but faces became strange