Brain plasticity exists in counterpoint to "localizationism," the theory that the brain is innately divided into functional centers -- the "speech center," the "vision center" -- and that these centers are hardwired to do one thing. It also exists in counterpoint to the idea that what plasticity the brain has, it loses in adult life, so that we become innately more set in our ways as we age.
Doidge, a medical doctor and psychoanalyst, puts forth a good case for the notion that our brain's propensity for wiring in certain ways is only that, a propensity, one that can be overcome by circumstance, force of will, training and injury, for better or for worse. Working like a biographer, Doidge gives us compelling personal histories of patients and doctors who've demonstrated the remarkable plasticity of the brain, right up to a woman who was literally born with one entire side of her brain missing, who nevertheless walks, talks, thinks, votes, holds down a job and so on -- having plastically retasked her remaining half-brain into taking on the tasks more generally assigned to the missing hemisphere.
Doidge's case histories are remarkable in that they demonstrate the spectrum of rewiring that the brain is capable of -- and the spectrum of difficulty associated with different kinds of rewiring. A patient whose balance-determining organs are burned out by a medication overdose, who has spent years falling, hurting herself, sick and depressed, learns to use a prosthetic that transmits positional data to her tongue in mere minutes, trains for hours, and receives days' worth of benefits, eventually recovering her life. On the other hand, stroke victims who've lost the regions of their brains that controlled certain parts of their bodies or certain kinds of thoughts have to train intensively, in a gruelling regime that demands everything they have, but they, too, stage remarkable recoveries in very short time.
From autism to ADD, Doidge's heavily footnoted tour through the cutting-edge of neuroplastic research, therapies and theories inspires on every page, with the message that you can think yourself different -- change the patterns of association, change the underlying physical substrate in your head. Your limitations can be smashed, your talents honed to new heights. An appendix called "The Culturally Modified Brain," even goes some way to discussing the way that our cultural outlooks (long acknowledged to having been shaped by our brains) can also shape our brains -- changing not just how we interpret our sensory data, but the limits and capacity of the neuronal structures that process sensory data.
Ultimately, this is one of the most hopeful and fascinating popular science books I've read, a book showing how science underpins the idea of positive thinking as a force for good.