The history of Sigmund Freud's approach to the mechanisms of the mind has exhibited some tumultuous changes over the past century. Norman Doidge reminds us that Freud developed a thesis about the mind's plasticity over time. Freud's psychotherapy - irrespective of some questionable methods - was designed to allow the mind to search within itself and change outward behaviour by identifying memories hidden or repressed. However, after Freud, researchers using diagnoses of stroke or brain-injury victims, "mapped" areas in the brain for function. The first of these was the speech-producing region now named Broca's Area, after Paul Broca, its discoverer in the mid-19th century. Brain modularity, or "localization" as Doidge deems it, became the norm in brain research for decades following Broca. In this fine account of the history or recent brain studies, Doidge addresses a new concept being used to both treat and train - brain "plasticity".
Rewiring of the brain isn't a new concept. Among the more famous examples of how the brain reacts to challenges from the rest of the body is the concept known as "phantom limbs". Patients suffering amputations have complained of itchiness or pain seeming to emanate from the lost limb. V.S. Ramachandran and his colleagues have described this phenomenon in detail. "Rama" is but one of the researchers Doidge parades in a receiving line of innovative cognitive specialists. One of his more noteworthy is Michael Merzenich, who Doidge declares is the "world's leading researcher in brain plasticity". Merzenich followed the work of Wilder Penfield at McGill University in Montreal. Penfield used electrical probes to map the regions of the brain to identify which areas produced specific reactions. Penfield's work reinforced the consensus regarding "localization". Doidge goes so far as to deem neuroscience as long dominated by "localizationism" - a form of dogma. Merzenich, on the other hand used more refined equipment than available to Penfield, has made vast strides with closer detail. His work also demonstrated that "lost areas" in the brain have their duties taken up in other regions. The brain, he demonstrated, can "re-wire" itself - and in more than one way. The brain, then, isn't dominated by genetically assigned "localizations". It's "plastic" and able to change, through training or even using its own resources. In a sense, Freud's original concept has been vindicated by recent research.
Doidge follows the work of dozens of researchers who have revealed examples of this re-mapping activity. They investigate how stroke patients can learn to use limbs rendered unresponsive. The treatment seems bizarre - restrain the good limb so it will not replace the useless one. In a short time, the unresponsive limb begins to respond as the brain is forced to seek new pathways. Patient recovery has been almost spectacular, according to Doidge. He stresses that the theme is "use it or lose it" throughout the book, but is especially true in stroke victims. Where traditional therapy enhanced the capabilities of the working limb, brain plasticity demonstrates that recovering use of an affected limb should be favoured. This new therapy can be successfully applied months, or even years, after the stroke event. In this author's hands, these accounts read like a script for a car-salesman sitcom. He may be correct in his views, but nothing in brain sciences is entirely positive, as history has demonstrated.
There's more than just therapy in brain plasticity achievements. In Asia, particularly Japan, babies are born with ability to form the sound for the letter "L". Since Japanese doesn't contain any words with that sound, children lose the capacity to pronounce it. A new programme, using slowly sounded words can actually recover the pronunciation in immigrants to North America. The technique is an indicator of what Doidge refers to as "plasticity competition". Although the brain appears to re-route signals throughout the brain simply during daily use, there is also the possibility of patterns settling in and resisting change. Doidge refers to this as the "plastic paradox", and sees it as the way habits are formed and retained - even against good sense.
While Doidge has provided a comprehensive look at how recent research has overthrown the notion of "one area - one behaviour", there are numerous questions remaining. How does the mechanism work? What triggers neurons to reach out to make new connections? Is anything already in place displaced, or are idle synapses or dendrites now put to work? Does the old notion of our using "only 10 per cent. of our brain" - an cliché long dismissed by neuroscientists - have some validity, after all? Although two Appendices enlarge greatly on this overview - one on culture and another on "Progress", brain mechanics in this process remain obscure. This shortcoming requires vast amounts of further research but in no way diminishes Doidge's accomplishment. This book will remain a major element in the history of brain studies for some time. Written for any reader who has a brain, the author deserves the fullest praise for his accomplishment. The five stars is given a bit grudgingly, but this book requires the widest exposure possible. [stephen a. haines - Ottawa, Canada]