From neuron to brain

Electroencephalography and Clinical Neurophysiology, 1 9 7 7 , 4 3 : 7 8 1 - - 7 8 4

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© Elsevier/North-Holland Scientific Publishers, Ltd.

BOOK REVIEWS

edited by H. PETSCHE and JOHN R. HUGHES

Principles o f neurobiological signal analysis. -- E.M. Glaser and D.S. Ruchkin (Academic, New York, 1976, 471 p., $ 21.50). It is excellent that Glaser and Ruchkin have written this book, which they and many other neurobiological signal analysts (including this reviewer) knew ought to be written. It very thoroughly covers a broad range of topics: general properties o f biological signals, basics of signal processing, power spectra and covariance functions, evoked potentials (as treated by averaging and discriminant analysis, principal components and varimax analyses), spontaneous and driven single-neuron activity, several- and multiple-unit activity, and analysis of the relations between wave and unit activity. The reason such a book has not been written before may well be the difficulty of introducing such a broad range of topics and techniques to the neurobiologist who has had little prior acquaintance with signal analysis, without making immediate and large demands on his (possible weak) skills at mathematical manipulation, and on his (probably weak) knowledge of the properties of mathematical concepts as they approximately apply to empirical data. Since this is the first attempt at that difficult task, it would be easy to criticize the ways in which the authors have not succeeded in writing 'the perfect b ook' on this subject. However, they have written a good book; this review will describe how it may be used. The proper user of this book either ( 1 ) k n o w s the subject fairly well, and merely wants a reference book to remind him of specific techniques and their background; or else (2) uses this book as a guide to what to study, but studies each topic from additional sources, and/or consults regularly with a sympathetic mathematical or engineering colleague, who re-explains the concepts he has just studied. I base this somewhat negative recommendation on several factors: first, the book was rapidly prepared for publication, which reduced its cost and accelerated its appearance, but which also resulted in a moderate number of minor and major typographical errors, a few of which make whole sentences irrelevant or incomprehensible, or formulas quite wrong. Personal discussion with the authors suggests that a high rate of typographical errors may be limited to the first chapter; and incomplete checking by this reviewer tends to confirm that hypothesis. The authors state they will prepare a list of corrections, which will be available

by request (to either author, at the School of Medicine, University of Maryland, Baltimore, Ma., 21201). As a second reason for my warning about who should or should not use this book, many o f its discussions include statements which would need to be set in context more fully than an inexperienced reader could do for himself; indeed, some statements seem quite misleading, in, their present context and brief presentation, although possibly defensible, given sufficient explanation and context. As a third reason, the derivation of many o f the formulas requires considerable algebraic facility in the reader, and fairly often requires him to notice and apply properties of the quantities defined, which are not immediately obvious, and not mentioned by the authors. To have presented such explanations and context, and the algebraic properties utilized, would have made the book much longer, and possibly quite inhibiting to the second class of reader. Thus, we should he grateful to the authors for having done so much; but we should be careful not to expect to learn this important subject matter from their book alone. DONALD O. WALTER University of California, Los Angeles CA 90024 (U.S.A.)

From Neuron to Brain. -- S.W. Kuffler and J.G. Nicholls (Sinauer Assoc., Sunderland, Mass., 1976, 487 p., $ 1 2 . 0 0 ) This volume would be disappointing indeed were the reader to approach it as a reference text on neurophysiology. The authors, however, 'prefer' and in fact limit themselves to ' a personal and therefore restricted point o f view, presenting some of the advances of the past few d e c a d e s . . . ' In this context the works o f Hodgkin, Huxley, Katz, Miledi, and the authors themselves are heavily emphasized. This can hardly be considered inappropriate, but it does limit the degree to which neuronal integrative physiology is considered. For example, the presynaptic and postsynaptic electrophysiology of chemical and electrical synaptic transmission is lucidly described with remarkable completeness. The concept o f length constant is defined. Nevertheless, the concept, significance and relevance of disinhibition and defacilitaton are not considered. If the reader is not primarily concerned

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w i t h possible m e c h a n i s m s o f m o d u l a t i o n at c o m p l e x integrative levels o f t h e n e r v o u s s y s t e m , such as t h e cerebral c o r t e x , this r e p r e s e n t s a m i n o r or insignific a n t omission. In a n y case, t h e i n f o r m a t i o n t h a t is in fact p r o v i d e d w o u l d c e r t a i n l y p r o v i d e a firm basis for u n d e r s t a n d i n g t h e s e m o r e c o m p l e x m e c h a n i s m s o f s y n a p t i c m o d u l a t i o n were t h e r e a d e r t o be m a d e aware o f t h e i r existence. T h e r e is a h e a v y e m p h a s i s o n studies o f t h e invert e b r a t e species for t h e discussions o f m e c h a n i s m s o f a c t i o n p o t e n t i a l g e n e r a t i o n a n d p r o p a g a t i o n , as well as t r a n s m i t t e r release. T h e s e aspects o f p h y s i o l o g y are m o s t clearly d e m o n s t r a t e d in such species a n d in m o s t cases t h e r e is little d o u b t t h a t t h e same principles are t r u e for primates. C o n c e p t s related t o electrogenic m e t a b o l i c p u m p s , glial f u n c t i o n a n d p e r i p h e r a l s e n s o r y m e c h a n i s m s are d e v e l o p e d a n d specific applic a t i o n s o f t h e s e m e c h a n i s m s are described. T h e a p p e n d i x offers a simplified d e s c r i p t i o n o f c u r r e n t flow as related t o simple circuits. T h e b o o k 'is d i r e c t e d t o t h e reader w h o is curious a b o u t t h e w o r k i n g o f t h e n e r v o u s s y s t e m b u t does n o t necessarily have a specialized b a c k g r o u n d in t h e biological sciences.' This e f f o r t h a s b e e n r e m a r k a b l y successful. S i m p l i f i c a t i o n o f c o n c e p t s has n o t d e t r a c t e d f r o m precision or detail. T h e a b s e n c e o f differential e q u a t i o n s is refreshing a n d n o t h i n g is lost f r o m t h e i n f o r m a t i o n a l qualities o f t h e m a t e r i a l . T h e a t t e m p t t o relate t h e s e aspects o f n e u r o p h y s iology to a m o r e c o m p l e x s y s t e m such as t h e visual s y s t e m is less t h a n t o t a l l y successful. This section o c c u r s early in t h e t e x t a n d a c t u a l l y it m i g h t b e m o r e r e w a r d i n g to read t h e s e c t i o n a f t e r section 5. Nevertheless, readers w o u l d b e n e f i t m o s t if t h e y were able to read t h e t e x t in a s e q u e n t i a l m a n n e r . In this way t h e m a t e r i a l b e c o m e s m o r e cohesive a n d p e r h a p s m o r e i m p o r t a n t l y t h e y will c o m e t o u n d e r s t a n d t h e perspective o f t h e a u t h o r s . Use o f t h e i n d e x t o o b t a i n isolated bits o f i n f o r m a t i o n or references w o u l d be less rewarding. T h e - b o o k m a y b e r e c o m m e n d e d to all e x c e p t t h o s e w h o have a p a r t i c u l a r specialized i n t e r e s t in s y n a p t i c a n d m e m b r a n e p h y s i o l o g y . Since n e u r o n a l

physiology represents the foundation for understanding physiology in the clinical context, the clinical neurophysiologist would find it an especially pleasant and rewarding investment in time and effort. A N D R E W J. G A B O R University o f California at Davis, Davis, California 9 5 6 1 6 (U.S.A.)

EEG instrumentation and technology. E.T. Richey and R. Namon (C.C. Thomas, Springfield, 1976, 206 p. $ 22.50).

This b o o k is " d e s i g n e d to furnish d e f i n i t i o n s , concepts, e x p l a n a t i o n s a n d a p p l i c a t i o n s n e e d e d t o u n d e r s t a n d p r o p e r l y a n d use t h e E E G m a c h i n e a n d r e c o r d an e l e c t r o e n c e p h a l o g r a m " . T h e b o o k begins w i t h an i n t r o d u c t i o n t o t h e h i s t o r y of electricity a n d e l e c t r o n ics a n d m o v e s t h r o u g h t h e e v o l u t i o n of t h e e l e c t r o n i c r e c o r d e r t o a c h a p t e r o n basic electrical c o n c e p t s . T h e e l e c t r o e n c e p h a l o g r a p h is e x p l a i n e d a n d t h e use of its c o n t r o l s is discussed. E l e c t r o d e s , c a l i b r a t i o n , m o n t a g e s , localization t e c h n i q u e s , safety a n d grounding, artifacts, a n d t r o u b l e - s h o o t i n g are m a j o r areas o f discussion. P r o b l e m s in l o c a t i o n a n d d e t e r m i n a t i o n of p o l a r i t y are p r e s e n t e d a n d t h e r e is a small, b u t helpful, glossary o f p r e d o m i n a n t l y e l e c t r o n i c terms. T h r o u g h o u t this b o o k , t h e r e has b e e n a considerable a t t e m p t Lo simplify t h e technical language of E E G a n d electronics. This results in a t e x t w h i c h s h o u l d be read w i t h o u t m u c h difficulty b y b e g i n n i n g s t u d e n t s o f E E G A n u n f o r t u n a t e side-effect o f this a p p r o a c h is t h e inclusion o f a n u m b e r o f s t a t e m e n t s w h i c h are imprecise. F o r e x a m p l e , t o say t h a t " m o n o polar t e c h n i q u e . . , can give a clearer a n d m o r e accurate p i c t u r e . . . " p r o v i d e s m o r e i n f o r m a t i o n a b o u t t h e t r a i n i n g a n d p r e f e r e n c e o f t h e senior a u t h o r t h a n it d o e s a b o u t t h e actual a d v a n t a g e o f referential recording in c o m p a r i s o n to s h o r t d i s t a n c e scalp-to-scalp, sequential recording. S i m p l i f i c a t i o n also leads to some errors o f omission. T h u s , t h e p a r a g r a p h o n " b r a i n wave c a l i b r a t i o n " ( p . 7 9 ) suggests r e c o r d i n g from 01-A1 in all c h a n n e l s t o " c h e c k t h e r e c o r d i n g circuits o f t h e m a c h i n e or t o d e t e r m i n e possible m a l f u n c t i o n o f a n y amplifier or 60 cycle a r t i f a c t . " T h e r e is n o m e n t i o n o f t h e reasons t h a t o n e p e r f o r m s this test: n a m e l y , to c h e c k t h e r e j e c t i o n o f in-phase activity at w o r k i n g e l e c t r o d e imp e d a n c e s a n d to e x a m i n e t h e linearity o f p e n r e s p o n s e t o a range o f low to high a m p l i t u d e signals (hysteresis). T h r o u g h o u t t h e t e x t t h e r e are n u m e r o u s illustrat i o n s o f good quality. T h e s e will be very h e l p f u l t o s t u d e n t s in u n d e r s t a n d i n g w h y p h a s e reversals occur, h o w filters and p a p e r speed a f f e c t t h e a p p e a r a n c e of E E G activity, a n d h o w a r t i f a c t s m a y a p p e a r a n d even r e s e m b l e b r a i n wave activity. One w o u l d have h o p e d for a m o r e m o d e r n explan a t i o n o f r e f e r e n t i a l a n d s e q u e n t i a l recording. T h e use o f t h e t e r m " m o n o p o l a r " expresses t h e vain h o p e t h a t s o m e h o w t h e c h o s e n r e f e r e n c e will be inactive. This is n e v e r t r u e in t h e e l e c t r o n i c sense, rarely t r u e in t h e biologic sense, a n d o f t e n n o t t r u e in t h e E E G sense, especially w i t h t h e a u t h o r s p r e f e r r e d r e f e r e n c e , t h e earlobe. Even w h e n a d m i t t i n g t o t h e activity o f b o t h e l e c t r o d e s in t h e discussion o f " b i p o l a r " r e c o r d i n g , t h e issue is c o n f o u n d e d w h e n t h e a u t h o r s e m p h a s i z e t h e a d v a n t a g e o f long i n t e r - e l e c t r o d e d i s t a n c e s in such recording.