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Blindness and the electrical activity of the brain: Electroencephalographic studies of the effects of sensory impairment
447
BOOK REVIEWS effects of m e t a b o l i c activity on local b l o o d f l o w e m p l o y i n g O 4 - 2 - d e o x y g l u c o s e (M. Reivlch) T h i s is f o l l o w e d b y a s t u d y of t h e m e t a b o l i c effects of seizures ( P l u m et al) C o n t r a r y to w h a t h a s b e e n t h o u g h t up to now, t h e i n c r e a s e d m e t a b o l i s m of the c o n v u l s i n g b r a i n m a y n o t outstrip its a s s o c i a t e d increase in c e r e b r a l b l o o d f l o w if t h e c o m p e n s a t o r y rise in b l o o d p r e s s u r e is n o t p r e v e n t e d . H o w e v e r , even w h e n a n o x e m i a is p r e v e n t e d , repetitive seizures are s h o w n to deplete s o o n e r or later cerebral e n e r g y reserves with b r a i n i n j u r y " I f t h e b r a i n m u s t sacrifice v o l u m e or o s m o l a h t y , cellular v o l u m e is relatively p r e s e r v e d a n d o s m o l a l l t y is altered to p r o t e c t b r a i n f u n c t i o n " T h i s p r i n c i p l e is s u p p o r t e d b y m u c h evidence t h a t is r e v i e w e d in a clear, p r o v o c a t i v e a n d well w r i t t e n analysis of t h e effects of o s m o t i c stress (R A F i s h m a n ) T h i s article a n d the one t h a t f o l l o w s it, " B r a i n F u n c t i o n in U r e m i a " (G. H. G l a s e r ) s e e m timely. Studies of seizure activity distribution in t h e b r a i n a n d studies of seizure t h r e s h o l d in v a r i o u s k i n d s o f e x p e r i m e n t a l u r e m i a m a y h a v e s o m e special interest to r e a d e r s of this Journal T h e r e m a i n i n g subjects are m o r e diverse, o f t e n reflecting n e w c h e m i c a l t e c h n i q u e s , t h e y i n c l u d e studies of spinal fluid peptides e m p l o y i n g liter q u a n tities ()) of goat C S F a n d studies of t h e ),-glutamyl cycle, a m i n o acid t r a n s p o r t a n d the b l o o d b r a i n barrier_ T h e e n z y m a t i c defects in a c u t e i n t e r m i t t e n t p o r p h y r i a h a v e b e e n greatly clarified. P a p e r s o n c a t e c h o l a m i n e f u n c h o n s in s c h i z o p h r e n i a , p s y c h i a t r i c d i s t u r b a n c e s in e n d o c r i n e disease, l e a d e n c e p h a l o p a thy, m a l n u t r i t i o n a n d b r a i n d e v e l o p m e n t , a n d v i t a m i n r e s p o n s i v e i n h e r i t e d disease r o u n d o u t t h e v o l u m e D i s c u s s i o n s by p a n e l m e m b e r s a r e t r a n s c r i b e d a n d included_ T h e r e is a n a d e q u a t e index. T h i s w a s a g o o d m e e t i n g a n d this is a g o o d b o o k It will p r o b a b l y be c o n s u l t e d as o f t e n a n d be as wellt h u m b e d as its predecessor.
JOLYON S TUCKER
Hart/ord Hospital, Hart/ord, Conn. 06115 (U.S.A )
Blindness and the electrical activity of the brain: Electroencephalographic studies of the effects of sensory impairment.--L. A. Novikova. Translated from the Russian by B Sznycer and L. Zielinski. Z. S. Jastrzembska (Editor). (American Foundation for the Blind, New York, 1973, 341 pp. $9.00). Since the imtxal analyses of the E E G of m a n by Berger, and by Adrian and Matthews the relation between the alpha r h y t h m and blindness has been a matter of great theoretical slgmficance, and of controversy This book by Novlkova is of major importance, not only because it conclusively settles this issue, but because it also demonstrates that this c o m m o n characteristic of the electrical activity of the h u m a n brain,
the alpha rhythm, occurs only in those individuals who have experienced pattern vision during their developmental years It thus relates directly to the fascinating and rapidly accumulating body of fact showing that the phymology and a n a t o m y of the brain, particularly of the visual cortex, is significantly determined by the nature of its afferent input during the early stages of postnatal development Novlkova finds that the alpha r h y t h m is entirely absent m all individuals lacking pattern vision for the first 1-2 years of life Her data are definitive since she has been able to record from 236 in&vtduals blinded to various degrees at all ages from birth to maturity In regard to the effect of bhndness upon the E E G there is an interaction between degree of visual impairment and age at which bhndness occurred, but the relation has wide m&vldual varlabdlty and IS not set forth in detail Apparently some individuals may still retain an alpha rhythm even if all retinal input is lost m later life The general rule, however, is not only that the alpha rhythm IS poorly developed or absent in individuals having a visual acuity < 0 05 (t,e, lacking all pattern perception), but that the amplitude of the E E G In all areas is greatly reduced, and a Rolan&c r h y t h m can be observed in 40°o of the blind compared to an incidence of about 3 13",, m normal mdwlduals The absence of alpha r h y t h m in m a n y of the bhnd had sometimes been attributed to a heightened level of alertness in these individuals Novlkova ingeniously &spells th~s notion by showing a normal course of habituation m the E E G arousal reaction in the blind, and noting that In the fully habituated state there is no appearance of the alpha r h y t h m In similar vein, the E E G of the deaf Is found to be entirely normal The presentation is occasionally repetitious, but provides a complete and thoughtful review of the relevant literature Novikova confirms the'fact that sharp spikes are sometimes seen in the occipital areas m the blind, but she does not pursue the nature of this abnormality, nor is there any mentIon of the n y s t a g m u s of the blind Perhaps her data will permit a retrospective analysis, for there is now reason to suspect that these occipital spikes in the blind might be related to saccadic eye m o v e m e n t s NegrSo and I have found that all blind squirrel monkeys or macaques &splay some form of nystagmus, and Sakakura discovered that each saccade is usually followed by a sharp spike in the strtate cortex of these totally blind monkeys (Eletttoenceph thn PCeurophysiol, 1969, 27 687) In this book Novikova also summarizes her extenswe studies on rabbits under various conditions of visual or olfactory deprivation, e 9 . enucleatlon, prolonged periods without light, destruction of olfactory eplthehum The experiments on the olfactory system are particularly interesting as they study the influence of deafferentatlon upon the prominent r h y t h m s of the olfactory bulb, and present as well an analysis of underlying single unit activity I do not consider the work on visual deprivation to be as successful First. I am perhaps prejudiced m my surprise that an animal with crepuscular or nocturnal habits should undergo such rapid and profound alteration of its E E G as Novlkova reports for rabbits merely as a consequence of their being kept m darkness If this be true, should one not suspect some
448 hormonal alteration e g , in ACTH, which would indirectly influence the recording of electrical activity of the brain, rather than ascribing the change to a direct effect of prolonged darkness on the global organization of neural activity 9 In any event, there is a simpler interpretation which the author seems to have overlooked, or at least has failed to control specifically This IS that the electrical activity registered from implanted electrodes gradually becomes attenuated as a consequence of their being walled off and/or being moved away from neural tissue by growth of connective tissue or bone Thus, the gradual diminution of the EEG consistently seen with time after onset of "deprivation" probably represents this process to at least some degree The animals seem to have shown some "recovery" upon restoration of the normal h g h ~ d a r k cycle which would contradict the foregoing thesis Recovery, however, was often "'mcomplete", so that the true situation remains somewhat unresolved There was no behavioral evaluation of the rabbits' visual capabilities after their stay in the dark for several weeks The reader should be aware that the translators and
BOOK REVIEWS editor, not the author, are to blame for such peculiarities as "oblong brain" (medulla oblongata). "counting block" (counting circuit), "Gracloll bundles" (optic radiation of Gratlolet), etc The double transliteration into and out of the Cyrillic alphabet inevitably takes its toll of the uninitiated Cragg and Temperley are amusingly credited with writing about ferromagnetic neurons rather than applying to neural populations the domain theory of magnetic fields, and Wllfrld E Le Gros Clark finally gets his just reward for having such a memorable but bibliographically dlfficuh i~ame in visual neuroanatomy, here becoming two people, Lc Gros and Clark These interesting flaws do not detract from the major value of this book. a definitive work in its mare theme, and it deserves a wide audience
ROBERT W DOT's, SR Cente~ /or Bram Research, Uml erstti' o! Roches'ter, Rochestep, l'v Y 1 4 6 4 2 ( U S A )
BOOK REVIEWS effects of m e t a b o l i c activity on local b l o o d f l o w e m p l o y i n g O 4 - 2 - d e o x y g l u c o s e (M. Reivlch) T h i s is f o l l o w e d b y a s t u d y of t h e m e t a b o l i c effects of seizures ( P l u m et al) C o n t r a r y to w h a t h a s b e e n t h o u g h t up to now, t h e i n c r e a s e d m e t a b o l i s m of the c o n v u l s i n g b r a i n m a y n o t outstrip its a s s o c i a t e d increase in c e r e b r a l b l o o d f l o w if t h e c o m p e n s a t o r y rise in b l o o d p r e s s u r e is n o t p r e v e n t e d . H o w e v e r , even w h e n a n o x e m i a is p r e v e n t e d , repetitive seizures are s h o w n to deplete s o o n e r or later cerebral e n e r g y reserves with b r a i n i n j u r y " I f t h e b r a i n m u s t sacrifice v o l u m e or o s m o l a h t y , cellular v o l u m e is relatively p r e s e r v e d a n d o s m o l a l l t y is altered to p r o t e c t b r a i n f u n c t i o n " T h i s p r i n c i p l e is s u p p o r t e d b y m u c h evidence t h a t is r e v i e w e d in a clear, p r o v o c a t i v e a n d well w r i t t e n analysis of t h e effects of o s m o t i c stress (R A F i s h m a n ) T h i s article a n d the one t h a t f o l l o w s it, " B r a i n F u n c t i o n in U r e m i a " (G. H. G l a s e r ) s e e m timely. Studies of seizure activity distribution in t h e b r a i n a n d studies of seizure t h r e s h o l d in v a r i o u s k i n d s o f e x p e r i m e n t a l u r e m i a m a y h a v e s o m e special interest to r e a d e r s of this Journal T h e r e m a i n i n g subjects are m o r e diverse, o f t e n reflecting n e w c h e m i c a l t e c h n i q u e s , t h e y i n c l u d e studies of spinal fluid peptides e m p l o y i n g liter q u a n tities ()) of goat C S F a n d studies of t h e ),-glutamyl cycle, a m i n o acid t r a n s p o r t a n d the b l o o d b r a i n barrier_ T h e e n z y m a t i c defects in a c u t e i n t e r m i t t e n t p o r p h y r i a h a v e b e e n greatly clarified. P a p e r s o n c a t e c h o l a m i n e f u n c h o n s in s c h i z o p h r e n i a , p s y c h i a t r i c d i s t u r b a n c e s in e n d o c r i n e disease, l e a d e n c e p h a l o p a thy, m a l n u t r i t i o n a n d b r a i n d e v e l o p m e n t , a n d v i t a m i n r e s p o n s i v e i n h e r i t e d disease r o u n d o u t t h e v o l u m e D i s c u s s i o n s by p a n e l m e m b e r s a r e t r a n s c r i b e d a n d included_ T h e r e is a n a d e q u a t e index. T h i s w a s a g o o d m e e t i n g a n d this is a g o o d b o o k It will p r o b a b l y be c o n s u l t e d as o f t e n a n d be as wellt h u m b e d as its predecessor.
JOLYON S TUCKER
Hart/ord Hospital, Hart/ord, Conn. 06115 (U.S.A )
Blindness and the electrical activity of the brain: Electroencephalographic studies of the effects of sensory impairment.--L. A. Novikova. Translated from the Russian by B Sznycer and L. Zielinski. Z. S. Jastrzembska (Editor). (American Foundation for the Blind, New York, 1973, 341 pp. $9.00). Since the imtxal analyses of the E E G of m a n by Berger, and by Adrian and Matthews the relation between the alpha r h y t h m and blindness has been a matter of great theoretical slgmficance, and of controversy This book by Novlkova is of major importance, not only because it conclusively settles this issue, but because it also demonstrates that this c o m m o n characteristic of the electrical activity of the h u m a n brain,
the alpha rhythm, occurs only in those individuals who have experienced pattern vision during their developmental years It thus relates directly to the fascinating and rapidly accumulating body of fact showing that the phymology and a n a t o m y of the brain, particularly of the visual cortex, is significantly determined by the nature of its afferent input during the early stages of postnatal development Novlkova finds that the alpha r h y t h m is entirely absent m all individuals lacking pattern vision for the first 1-2 years of life Her data are definitive since she has been able to record from 236 in&vtduals blinded to various degrees at all ages from birth to maturity In regard to the effect of bhndness upon the E E G there is an interaction between degree of visual impairment and age at which bhndness occurred, but the relation has wide m&vldual varlabdlty and IS not set forth in detail Apparently some individuals may still retain an alpha rhythm even if all retinal input is lost m later life The general rule, however, is not only that the alpha rhythm IS poorly developed or absent in individuals having a visual acuity < 0 05 (t,e, lacking all pattern perception), but that the amplitude of the E E G In all areas is greatly reduced, and a Rolan&c r h y t h m can be observed in 40°o of the blind compared to an incidence of about 3 13",, m normal mdwlduals The absence of alpha r h y t h m in m a n y of the bhnd had sometimes been attributed to a heightened level of alertness in these individuals Novlkova ingeniously &spells th~s notion by showing a normal course of habituation m the E E G arousal reaction in the blind, and noting that In the fully habituated state there is no appearance of the alpha r h y t h m In similar vein, the E E G of the deaf Is found to be entirely normal The presentation is occasionally repetitious, but provides a complete and thoughtful review of the relevant literature Novikova confirms the'fact that sharp spikes are sometimes seen in the occipital areas m the blind, but she does not pursue the nature of this abnormality, nor is there any mentIon of the n y s t a g m u s of the blind Perhaps her data will permit a retrospective analysis, for there is now reason to suspect that these occipital spikes in the blind might be related to saccadic eye m o v e m e n t s NegrSo and I have found that all blind squirrel monkeys or macaques &splay some form of nystagmus, and Sakakura discovered that each saccade is usually followed by a sharp spike in the strtate cortex of these totally blind monkeys (Eletttoenceph thn PCeurophysiol, 1969, 27 687) In this book Novikova also summarizes her extenswe studies on rabbits under various conditions of visual or olfactory deprivation, e 9 . enucleatlon, prolonged periods without light, destruction of olfactory eplthehum The experiments on the olfactory system are particularly interesting as they study the influence of deafferentatlon upon the prominent r h y t h m s of the olfactory bulb, and present as well an analysis of underlying single unit activity I do not consider the work on visual deprivation to be as successful First. I am perhaps prejudiced m my surprise that an animal with crepuscular or nocturnal habits should undergo such rapid and profound alteration of its E E G as Novlkova reports for rabbits merely as a consequence of their being kept m darkness If this be true, should one not suspect some
448 hormonal alteration e g , in ACTH, which would indirectly influence the recording of electrical activity of the brain, rather than ascribing the change to a direct effect of prolonged darkness on the global organization of neural activity 9 In any event, there is a simpler interpretation which the author seems to have overlooked, or at least has failed to control specifically This IS that the electrical activity registered from implanted electrodes gradually becomes attenuated as a consequence of their being walled off and/or being moved away from neural tissue by growth of connective tissue or bone Thus, the gradual diminution of the EEG consistently seen with time after onset of "deprivation" probably represents this process to at least some degree The animals seem to have shown some "recovery" upon restoration of the normal h g h ~ d a r k cycle which would contradict the foregoing thesis Recovery, however, was often "'mcomplete", so that the true situation remains somewhat unresolved There was no behavioral evaluation of the rabbits' visual capabilities after their stay in the dark for several weeks The reader should be aware that the translators and
BOOK REVIEWS editor, not the author, are to blame for such peculiarities as "oblong brain" (medulla oblongata). "counting block" (counting circuit), "Gracloll bundles" (optic radiation of Gratlolet), etc The double transliteration into and out of the Cyrillic alphabet inevitably takes its toll of the uninitiated Cragg and Temperley are amusingly credited with writing about ferromagnetic neurons rather than applying to neural populations the domain theory of magnetic fields, and Wllfrld E Le Gros Clark finally gets his just reward for having such a memorable but bibliographically dlfficuh i~ame in visual neuroanatomy, here becoming two people, Lc Gros and Clark These interesting flaws do not detract from the major value of this book. a definitive work in its mare theme, and it deserves a wide audience
ROBERT W DOT's, SR Cente~ /or Bram Research, Uml erstti' o! Roches'ter, Rochestep, l'v Y 1 4 6 4 2 ( U S A )