Mind how you go

Psychologists are often at variance with their neurological cousins, but psychologist Ian Robertson, fresh from the Cognition…

Psychologists are often at variance with their neurological cousins, but psychologist Ian Robertson, fresh from the Cognition and Brain Sciences Unit in Cambridge where he researched brain rehabilitation, takes his lead from the latter camp. The result is a breathless, impressionistic description of a brain "like a 20-watt lightbulb, continuously glowing "; itself "embroidered in a trembling web of 100 billion brain cells, each on average connected to 1000 others"; with every thought, sensation or response sending mini-surges of blood and electricity hither and thither, and leaving faint but permanent traces in one's synaptical wiring.

He cites recent neurological findings: that brain cells do regenerate, at least in the hippocampus (a tract of tissue associated with memory), and indeed that the brain can radically reconfigure itself after injury. He also cites evidence from many arm-amputees who, due to the proximity of sensory representations of hand and cheek on the surface of the brain, feel sensation in their "phantom" hand when their cheeks are stroked. For some reason, Robertson shies from reporting a similarly fascinating neural connection between genitals and feet - many leg-amputees have described tingles in phantom feet during sex.

Robertson argues that, although our somato-sensory strip is largely hard-wired by toddlerhood, much of our bulging neo-cortex is far more synaptically flexible. Engaged in learning and forgetting, it constantly reorganises its mesh of synapses through "Hebbsian learning" - long-term electrical potentiations of reinforced neural pathways - a process which Robertson poetically characterises as "mind sculpture".

He moves onto some odd experimental findings: that repeated mental rehearsals of a physical action can result in a small increase in muscle strength. A technique practised by injured athletes, such "pumping iron in the mental gym", Robertson hints, may even help rehabilitate a paralysis, by consciously restitching neural connections in a brain damaged by stroke or injury. Excited by such therapeutic hopes, he touches on the experiences of some arm-amputees with painfully clenched phantom limbs. In some cases, their agony is relieved (at least temporarily) by moving their remaining hand around in a mirror-box to visually simulate the phantom limb.

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Elsewhere, I would contest the basis and implications of Robertson's musings about the effects of "lower social-class backgrounds" on language acquisition in children - and, he even muses, synapse-formation. Citing a US study, he states that by the age of three, the average child of a professional family has had about 30 million words addressed to her - contrasting with 20 million for a working-class child, or only 10 million by families on welfare.

Scurrilous stuff, but Robertson hal-fcounters it with a London study from the Thatcher-boom 1980s, which found that home-based childminders talked to kids at least 50 per cent more than creche staff - resulting in larger early vocabularies. As a result, most of the worst developers among the children studied didn't come from underclass stock (only 6 per cent of whom could afford creches), but from highly educated professional families!

Robertson blithely marches through the heather of other controversial findings: that people with higher IQs display better brain recovery after injury; or, worse, that higher education helps protect you against Alzheimer's - a catchy idea guaranteed to hearten his more rambling academic brethren.

Overall, Robertson displays no clear vision here of the interaction of neurochemistry, physiology or greater functional architecture within the brain, and the second half of the book is a chatty, optimistic elaboration of the book's subtitle. Although a Scot, Robertson writes like an American, so psychology students at Trinity College Dublin can at least look forward to some upbeat lectures this autumn, as Robertson has just taken over as the new professor.

Mic Moroney is a freelance journalist