Nerved to look at mind
This is the decade of the brain. It is also the decade of popular science books (as witnessed by their increasing presence in the best-seller lists). There is thus a certain inevitability about Susan Greenfield's new "guided tour" of the human brain.
Greenfield is professor of pharmacology at Oxford and a rising star among British science popularisers. Following the success of her Royal Institution Christmas Lectures in 1994, she has become a regular lecturer,broadcaster and - through her fortnightly column in the Independent on Sunday - writer about science for a wide public. Since her own field is brain science - among other things, she works on Parkinson's disease - it is entirely appropriate that she should produce a book designed to introduce this field to non-specialists.
The Human Brain is the latest in the Science Masters series. Earlier books by, for example, John Barrow, Paul Davies and Richard Dawkins have firmly established the format for the series: all of the books are short, synoptic accounts of important ideas with a minimum of factual detail and few or no tables and illustrations. (Part of the object seems to be to keep the cover price down, though I see that this has now crept significantly above #163;10.)
Greenfield follows this format pretty closely. She starts with the centuries-old attempt to localise functions within the brain, and then moves swiftly through discussions of how different parts of the brain co-operate to achieve complex activities (such as moving or seeing), how nerve cells communicate with one another, and how the brain develops from conception to maturity, to a final encounter with the most intriguing and difficult matter of all: the nature of mind. Throughout, comprehensiveness is rightly abandoned in favour of a selective treatment of key issues, often in the light of recent research.
Greenfield is particularly good at explaining clearly how things work. Readers unfamiliar with how modern medical imaging techniques are transforming brain science will enjoy the descriptions of CAT scans, PET, MRI and all the rest; and those who know nothing about neurophysiology will benefit from her concise account of how nerve cells communicate with one another and why drugs such as heroin and cocaine have such dramatic effects on the brain.
In the section on mind, Greenfield uses recent work on memory to illustrate the strengths and weaknesses of contemporary brain science. Like most complex brain functions, memory is not easily localisable in any single area. Fascinating work in other animals has come close to identifying the links between biochemical changes in specific parts of the brain and remembered behaviour; but in humans, this has not proved possible because in our case "top-down organisation is as relevant as bottom-up mechanisms".
Greenfield is a reliable guide to the brain. Occasionally, her choice of similes appears rather inept (as, for example, when she compares the consistency of the brain in swift succession, first to "a soft-boiled egg" and then to "a raw egg" - surely these aren't the same? - and now and then,bits and pieces of rather dry scientific prose (for example, " . . . an aspect that is not immune to individual perturbation . . .") creep into what is generally a clear and confident prose style.
These minor quibbles apart, however, The Human Brain is an enjoyable and informative guide to one of the most exciting and fast-moving areas of contemporary science. It is ideally suited to readers who have no background in physiology but are curious to know more about what goes on in their heads.
The book doesn't answer all of the questions that the thoughtful reader might be inclined to ask, for the very good reason that brain science is still, relatively speaking, in its infancy. (In particular, we are still totally in the dark about the relationship between brain and mind.) But it makes clear how far we have come in our quest for an understanding of the brain, and where we should be looking for new insights in the future.
John Durant is assistant director (head of science communication) at the Science Museum and professor of public understanding of science, Imperial College, London.