Brain, Vol. 123, No. 4, 846-847,
April 2000
© 2000 Oxford University Press
Book Reviews |
FUNDAMENTALS OF FUNCTIONAL BRAIN IMAGING.
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Neurology Department, Royal Sussex County Hospital, Brighton, UK
The techniques of functional imaging are so complex that it may be tempting to glance at the pictures and assume that the method of production has unimpeachable scientific validity. The use of such images has extended far beyond the neuroscience community, to publications by pressure groups (often anxious to prove that their particular bias has scientific validity), advertisements in medical magazines (to persuade the prescriber of the merits of this or that particular drug) and to that bastion of accurate information, the national tabloid press. There is, after all, nothing to beat a colourful picture and a snappy headline to sell copy, opinions or drugs, and it is tempting to suggest an annual prize for the greatest abuse of a functional image. A foray through recent major neurology journals shows that at least one in 20 papers are functional imaging studies, a testament to their importance in the advancement of neuroscience and to their appeal to editors and readers alike.
One may not be able to avoid exposure to functional imaging, but there is surely a responsibility on those keen to cite such evidence to be able to give a coherent account of the way the study was carried out, of how reproducible the data are likely to be, and of the potential pitfalls in the technique and the design of the study that gave the images and results. This book, developed from a series of tutorials to neuropsychology students, provides a quick (it is only 134 pages long and can easily be read in an afternoon) introduction to the main techniques, and some of the difficulties in the design and interpretation of studies. It is a little too concise for those wishing to work in functional imaging, but does give an enthusiastic and comprehensible account for those with a passing interest in the field.
Part I covers basic concepts of imaging brain activation. The text is easy to follow and proceeds in a logical step by step pattern. The last section, `Questions of fidelity', considers reliability and validity.
Part II is a simple guide to MEG, functional MRI (fMRI) and PET. An explanation of the mechanism of MRI is a challenge to the greatest educator; here it is dealt with rather effortlessly before proceeding to an explanation of fMRI. The clarity with which the methods are explained may stem from the author's experience of group teaching, and these pages are more easily read than many produced by enthusiasts for the techniques. The illustrations are clear and appropriate. The description of each technique is followed by a few paragraphs on the fidelity of the imaging technique in question.
Part III looks more closely at typical functional imaging studies, beginning with the imaging of simple sensory and motor functions, then the study of `higher functions' and finally a brief survey of other applications. These chapters use typical and conflicting studies to make points; the conflicts are explained in terms of the arguments and comments made earlier in the book. The author dwells on some of the more philosophical aspects of imaging consciousness and behaviour, and is not slow to point out the limitations or the potential for over-interpretation of the results.
It has to be said that the author has a cautious and slightly cynical approach to the results of functional imaging studies. One might read a bias towards the value of MEG, with a nod to its superior temporal resolution, and activation PET studies are given greater space than ligand PET. Having activated the cynical cortex I would have liked a few more chapters. It would have been nice to see a review of the common methods of statistical analysis of images, and an interrogation of the assumptions within them (who was it that said there are lies, damned lies, statistics and the statistical interpretation of functional images?). A brief guide advising the reader how to pick a good study from a bad study (other than by whether it confirms one's theory) would have been useful, perhaps beginning with a look at the number of controls (from zero to one hundred in recent studies), the blinding procedures used (blinded functional imaging is not an oxymoron), and the use and abuse of the colour scale in image presentation (mea culpa).
This book fills a need and will be welcomed by anyone who is looking for a simple and rapid introduction to an influential and fascinating area in neuroscientific investigation. The level is that of a neuroscience degree but it should not be beyond GCSE students or Clinical Neurologists. It can be recommended, although at £45 it may be rather too expensive for its target readership.
Notes
1999. Lisse: Swets & Zeitlinger.
Price $72.00. Pp. 134. ISBN 90-265-1528-6.
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