9. 10. 11. 12. 13.
14. 15.
J. Szentagothai, P r o g r . Brain Res., 11, 155 (1964). M. Rethelyi and J. Szentagothai, in: S o m a t o s e n s o r y System (1973), p. 207. C . A . Fox and J. Eiehman, Stain Technol., 34, 39 (1959). I . S . Gazanova, O. S. Merkulova, and V. N. Chernigovskii, in: Questions on the Physiology of Enteroeeption [in Russian], Vol. 2, Leningrad (1965), p. 20. K . S . P r e d t e e h e n s k a y a , in: Neurophysiologic Mechanisms of Movement Coordination [in Russian], Leningrad (1972), p. 23.
P.G. Kostyuk, Fiziol. Zh. SSSR, 47, 1241 (1961). V.I. Saf'yants, S. A. Evdokimov, and Yu. N. Zubilov, Neirofiziologiya, 2_, 3 (1970).
RESTORATION FROG
Rana
OPTIC
A.
BEHAVIORAL
esculenta
NERVE V.
OF
RESPONSES
IN T H E
DURING
REGENERATION
OF
and Yu.
B.
FIBERS
Bastakov
Manteifel
UDC 591.484:597.84
The ganglion cells in the retinas of frogs exhibit a high degree of specialization. Accordingly, they may be divided into s e v e r a l functionally different, d i s c r e t e c l a s s e s . Retinal ganglion cells (RGC) of a given class are connected mainly to a specific p r i m a r y visual center [1-3], raising the question of the significance of this differentiation in r e t i n o - c e n t r a l paths in the organization of behavioral r e s p o n s e s . Of help in the investigation of this problem is the stability of the manifestation of s e v e r a l types of frog behavior which a r e evoked by visual stimuli and can be divided into a chain of sequentially c a r r i e d - o u t , c l e a r l y separable responses [4]. A theoretical examination of this problem, involving a c o m p a r i s o n of data regarding the p r o p e r t i e s of RGC of the different c l a s s e s and the angular dimensions o f the stimuli which evoke food-getting and avoidance behavior, has shown that any such stimulus can evoke the activation of RGC of s e v e r a l c l a s s e s -- depending on its distance f r o m the animal -- but that during the food-getting response RGC of Class II are a l w a y s activated in some degree [1,3, 5]. The c l e a r e s t theory of the significance of the RGC of different c l a s s e s for the initiation of different forms of behavior is the hypothesis of the detector organization of visually controlled behavior in frogs. According to this idea, food-getting behavior is initiated when impulses from Class II RGC a r r i v e in the tectum; the avoidance response is initiated by Class III RGC, the s e a r c h for shady shelter, by RGC of Class IV, and Class I RGC participate in the avoidance of obstacles [5]. Th e p r e s e n t communication presents the results of a study of the r e s t o r a t i o n of the f r o g ' s behavioral responses to visual stimulation during the regeneration of optic nerve fibers. As is known, after a section operation RGC axons r e g e n e r a t e and grow back to the same region of the brain in which they normally t e r m i nate; this leads to a r e s t o r a t i o n of the food-getting response [6,7]. In previous experiments on Rana tempor a r i a it has been shown that, at a t e m p e r a t u r e of 18-20 ~ RGC with large excitatory receptive fields (Classes III and IV) r e s t o r e connections with the tectum 20 days after operation, and RGC with small excitatory r e c e p tive fields (Classes I and II), 60 days afterward [8]. This difference in the rate of regeneration of axons of the different RGC allows for a new approach to the experimental investigation of the significance of RGC of the various c l a s s e s in the organization of visually directed behavior: comparing the r e s t o r a t i o n of behavioral responses with details of the r e s t o r a t i o n of retinotectal connections as revealed by electrophysiological studies of the same individuals. The experiments were p e r f o r m e d with Rana esculenta, since certain features of the biology of these frogs make them m o r e convenient subjects for such investigation than Rana t e m p o r a r i a . The optic nerve of a narcotized animal was sectioned in a cavity in the skull at the chiasm. After 3-5 days, unilaterally operated animals were placed in a pond; bilaterals were put in a drainless pond, where they lived for s e v e r a l months. P e r i o d i c a l l y , the animals' behaL a b o r a t o r y of Comparative Vertebrate Neurophysiology, A. N. Severtsov Institute of Evolutionary Morphology and Ecology of Animals, A c a d e m y of Sciences of the USSR, Moscow. T r a n s l a t e d from Zhurnal l~volyutsionnoi Biokhimii i Fiziologii, Vol. 12, No. 5, pp. 489-490, S e p t e m b e r - O c t o b e r , 1976. Original article submitted June 23, 1976.
196
0097-0549/78/0902-0196507.50
9 1979 Plenum Publishing Corporation
Oo
~ OoO12
oa ob
Fig. 1. Sequential r e s t o r a t i o n of retinoc e n t r a l connections during regeneration. I. Schematic figure of the frog brain; a r r o w s : three groups of optic fibers n e c e s s a r y for organization of three f o r m s of behavior; II. Tectal projection of r e t inal ganglion cells of Class HI (a), and Classes I and ]7 (b), 16-20 days (1), 55-60 days (2), and 90-100 days after operation (3).
vioral responses were tested by presenting them with dark targets (spheres 5-130 mm in diameter) suspended f r o m a long fishing pole [9]. Stimuli were presented to unilaterally operated individuals in the monocular field of vision of the appropriate eye. When interesting behavioral responses appeared, animals were caught, and the intact eye was removed. After more p r e c i s e study of these f r o g s ' r e s p o n s e s , they were studied electrophysiologically in an acute experiment. The activity of the regenerating retino-tectal fibers was studied by means of the usual methods, using platinized m i c r o e l e c t r o d e s and presenting moving, flat, contrasting visual stimuli [1]. The experiments were p e r f o r m e d on 128 individuals in the s u m m e r s of 1973-1974 at the Institute 's biological station "Deep Lake. " During the r e s t o r a t i o n of the f r o g s ' vision, a c l e a r nonsimultaneity was observed in the appearance of the various f o r m s of visually driven behavior. Sixteen to twenty days after operation, "spontaneous movement" appeared and r e s p o n s e s to avoid obstacles o r jump upon them, as well as leaps into dark and light a p e r tures positioned above the level of the ground. All these responses can be united in one group, since they require the perception of l a r g e , nonmoving objects and the determination of their position in space. Avoidance r e s p o n s e s appeared 55 days after operation, and food-getting responses after 90 days. Electrophysiologieal experiments revealed that both the sequence and the dates of restoration of retinotectal connections of RGC of the various c l a s s e s a r e s i m i l a r in Rana esculenta to those in Rana t e m p o r a r i a [8]. Experiments were p e r f o r m e d on animals in which one o r another form of visually driven behavior had appeared. The basic results a r e presented schematically in Fig. 1. In animals which perceived l a r g e , nonmoving objects (16-20 days after operation), it was not possible to d i s c o v e r RGC t e r m i n a l s in the tectum. Evidently, optic fibers still have not gro~vn back to the rectum at this t i m e , but have already grown back to some other visual center -- possibly, nuclei in the r o s t r a l thalamus. This is consistent with notions regarding the association of such behavioral responses in frogs with visual projections to the indicated nuclei, in which are to be found axon terminals coming from RGC which a r e excitable by an i n c r e a s e in illumination of the receptive field [2, 10]. In frogs in which the avoidance response has been r e s t o r e d , d i s c h a r g e s are r e c o r d e d in the tectum from axon terminals of RGC having large excitatory receptive fields, m o s t l y of Class HI (of 50 units recorded, 43 were of Class III, 5 of Class IV, and 2 of Class I). Generally, the avoidance response was observed only in those individuals in which terminals from Class III RGC had c o v e r e d nearly the entire tectal s u r f a c e , so that the map of the retino-tectal projection [7] was close to normal for this c l a s s . These data a r e consistent with ideas concerning the leading significance of Class III RGC for the formation of the avoidance response [5], but they do not support the ideas of the same authors concerning the participation of Class I RGC in obstacle avoidance and Class IV RGC in the choice of shelter. Terminals of Classes I and IIRGC were p r e s e n t in the tecta of animals exhibiting food-getting r e s p o n s e s , these behavioral r e sponses being initiated from those regions of the retina from which the axons of these RGC had grown back to the tectum and established synaptic connections; the f i r s t food-getting responses were evoked, naturally, in the a n t e r i o r regions of the visual field. It is possible that the difference between the avoidance and food-getting responses (avoidance requires r a t h e r complete retino-tectal projections) is explained by the necessity for major intratectal integration o v e r a significant part of the visual field. In the first days after the appearance of the avoidance and food-getting responses (55-70 days and 90-120 days, respectively), they were evoked by moving stimuli of any size; the responses were perfected in proportion to the degree of perfection of the retinotectal projection. The food-getting responses at f i r s t were manifested by opening the mouth and sticking out the tongue -- independent of the distance to the target. According to the degree of expansion of the projection of Classes i and IIRGC, turning to the t a r g e t appears and, still later, approach (i. e . , determining the distance t o the food object s e e m e d to be the m o s t finely organized part of food-getting behavior).
197
F o r this r e a s o n , in spite of the fact that f r o g s ' reactions to visual stimuli n o r m a l l y a r e d e t e r m i n e d not only by the a n g u l a r d i m e n s i o n s of the objects viewed but a r e c a r r i e d out with due r e g a r d for the distance to them [9], s p e c i a l i z e d "channelling" of the visual information entering the f r o g ' s brain f r o m RGC of p a r t i c u l a r c l a s s e s is n e c e s s a r y f o r organizing c e r t a i n biologically d i v e r s e f o r m s of behavior. F r o m this point of view, one could s p e a k of not one -- o r even two [10] -- visual s y s t e m s , evidently, but of s e v e r a l visual s y s t e m s in anuran amphibians and, p r o b a b l y , in o t h e r l o w e r v e r t e b r a t e s . In the r e t i n o - t e c t a l division, one m a y suppose that there is special significance in the level of distribution of the synaptic contacts f o r m e d by the axons of RGC of a p a r t i c u l a r c l a s s . The s t r a t i f i e d distribution of the t e c t a l t e r m i n a l s of RGC of different c l a s s e s o c c u r s not only in the n o r m a l animal [1,3], but gradually is r e s t o r e d also a f t e r the r e g e n e r a t i o n of retinot e c t a l f i b e r s (according to [11], as well as o u r own observations}. LITERATURE 1. 2, 3.
4. 5. 6. 7. 8. 9. !0. 11.
CITED
H . R . Maturana, J . Y. Lettvin, W. S. MacCulloch, and W. H. P i t t s , J. Gen. P h y s i o l . , 4__33,N o . 6 , P a r t 2, 129 (1960). W.R.A. Muntz, J . N e u r o p h y s i o l . , 2__55, 712 (1962). O . J . G r f / s s e r and U. G r f / s s e r - C o r n e h l s , in: H. Autrum et a l . , Handbook of Sensory Physiology, Vol. VH/3a, Central P r o c e s s i n g of Visual Information, P a r t A. (R. J u n g , e d . ) , S p r i n g e r - - V e r l a g , Berlin (1973), p. 333. D. Schneider, Biol. Z b l . , 7_33, 225 (1954). I . N . P i g a r e v and G. M. Zenkin, Zh. Vyssh. Nervn. D e y a t . , 2_.0.0, 170 (1970). R . W . S p e r r y , J . N e u r o p h y s i o l . , 7 , 57 (1944). R . M . G a z e , The F o r m a t i o n of N e r v e Connections, Acad. P r e s s , New Y o r k (1970). V . M . Vinogradova, V. A. Bastakov, L. N. D ' y a c h k o v a , and Yu. B. Mantefel', Neirofiziologiya, 5, 611 (1973). E . I . Kiseleva and Yu. B. Manteifel'., Zool. Z h . , 5__33,1817 (1974). D. Ingle, Science, !81, 1053 (1973). M . J . Keating and R. M. G a z e , Brain R e s . , 2_~1, 197 (1970).
SOMATOSENSORY L.
S. A l e e v
EVOKED and
Yu.
POTENTIALS P.
IN HEALTHY
PEOPLE UDC 612.825
Varezhkin
The: r e s u l t s of a study of s o m a t o s e n s o r y evoked potentials r e c o r d e d in 37 healthy stlbjects of both s e x e s a r e d e s c r i b e d . C o m p a r i s o n of the r e s u l t s of t e s t s on t h r e e age subgroups showed selectivity in the change in l a t e n e i e s and a m p l i t u d e s of w a v e s of the s o m a t o s e n s o r y r e s p o n s e s depending on the s u b j e c t ' s age. I p s i l a t e r a l r e s p o n s e s show g r e a t e r v a r i a b i l i t y but a l o w e r amplitude and frequency of a p p e a r a n c e of the individual components than c o n t r a l a t e r a l r e s p o n s e s . T h e i r latent p e r i o d s a l s o w e r e longer than those of the c o n t r a l a t e r a l r e s p o n s e s . INTRODUCTION N u m e r o u s investigations of cortical evoked potentials (EPs) in a n i m a l s have shown that the EP method is highly effective as a m e a n s of studying the conducting pathways and connections in the CNS. F o r v a r i o u s r e a s o n s of a technical nature human E P s have r e c e i v e d f a r l e s s study. When deciding to investigate s o m a t o s e n s o r y E P s of the human b r a i n it was r e a l i z e d that information on the c h a r a c t e r and p r o p e r t i e s of t h e s e r e s p o n s e s is scanty and s o m e t i m e s c o n t r a d i c t o r y . T h i s is the c a s e , for e x a m p l e , with the concept of " n o r m a l " as applied to c o n t r a l a t e r a l r e s p o n s e s and the g e n e s i s of i p s i l a t e r a l r e s p o n s e s . Another i n t e r e s t i n g p r o b l e m for study was the possibility of using data on E Ps in clinical neurology f o r diagnostic p u r p o s e s and also for investigating cortical c o m p e n s a t o r y m e c h a n i s m s in the c o u r s e of r e c o v e r y
Institute of C y b e r n e t i c s , A c a d e m y of Sciences of the Ukrainian SSR, Kiev. T r a n s l a t e d f r o m N e i r o f i z i o logiya, Vol. 8, No. 5, pp. 447-454, S e p t e m b e r - O c t o b e r , 1976. Original a r t i c l e submitted N o v e m b e r 6, 1975.
198
0097-0549/78/0902-0198507.50
9 1979 Plenum Publishing Corporation
14. 15.
J. Szentagothai, P r o g r . Brain Res., 11, 155 (1964). M. Rethelyi and J. Szentagothai, in: S o m a t o s e n s o r y System (1973), p. 207. C . A . Fox and J. Eiehman, Stain Technol., 34, 39 (1959). I . S . Gazanova, O. S. Merkulova, and V. N. Chernigovskii, in: Questions on the Physiology of Enteroeeption [in Russian], Vol. 2, Leningrad (1965), p. 20. K . S . P r e d t e e h e n s k a y a , in: Neurophysiologic Mechanisms of Movement Coordination [in Russian], Leningrad (1972), p. 23.
P.G. Kostyuk, Fiziol. Zh. SSSR, 47, 1241 (1961). V.I. Saf'yants, S. A. Evdokimov, and Yu. N. Zubilov, Neirofiziologiya, 2_, 3 (1970).
RESTORATION FROG
Rana
OPTIC
A.
BEHAVIORAL
esculenta
NERVE V.
OF
RESPONSES
IN T H E
DURING
REGENERATION
OF
and Yu.
B.
FIBERS
Bastakov
Manteifel
UDC 591.484:597.84
The ganglion cells in the retinas of frogs exhibit a high degree of specialization. Accordingly, they may be divided into s e v e r a l functionally different, d i s c r e t e c l a s s e s . Retinal ganglion cells (RGC) of a given class are connected mainly to a specific p r i m a r y visual center [1-3], raising the question of the significance of this differentiation in r e t i n o - c e n t r a l paths in the organization of behavioral r e s p o n s e s . Of help in the investigation of this problem is the stability of the manifestation of s e v e r a l types of frog behavior which a r e evoked by visual stimuli and can be divided into a chain of sequentially c a r r i e d - o u t , c l e a r l y separable responses [4]. A theoretical examination of this problem, involving a c o m p a r i s o n of data regarding the p r o p e r t i e s of RGC of the different c l a s s e s and the angular dimensions o f the stimuli which evoke food-getting and avoidance behavior, has shown that any such stimulus can evoke the activation of RGC of s e v e r a l c l a s s e s -- depending on its distance f r o m the animal -- but that during the food-getting response RGC of Class II are a l w a y s activated in some degree [1,3, 5]. The c l e a r e s t theory of the significance of the RGC of different c l a s s e s for the initiation of different forms of behavior is the hypothesis of the detector organization of visually controlled behavior in frogs. According to this idea, food-getting behavior is initiated when impulses from Class II RGC a r r i v e in the tectum; the avoidance response is initiated by Class III RGC, the s e a r c h for shady shelter, by RGC of Class IV, and Class I RGC participate in the avoidance of obstacles [5]. Th e p r e s e n t communication presents the results of a study of the r e s t o r a t i o n of the f r o g ' s behavioral responses to visual stimulation during the regeneration of optic nerve fibers. As is known, after a section operation RGC axons r e g e n e r a t e and grow back to the same region of the brain in which they normally t e r m i nate; this leads to a r e s t o r a t i o n of the food-getting response [6,7]. In previous experiments on Rana tempor a r i a it has been shown that, at a t e m p e r a t u r e of 18-20 ~ RGC with large excitatory receptive fields (Classes III and IV) r e s t o r e connections with the tectum 20 days after operation, and RGC with small excitatory r e c e p tive fields (Classes I and II), 60 days afterward [8]. This difference in the rate of regeneration of axons of the different RGC allows for a new approach to the experimental investigation of the significance of RGC of the various c l a s s e s in the organization of visually directed behavior: comparing the r e s t o r a t i o n of behavioral responses with details of the r e s t o r a t i o n of retinotectal connections as revealed by electrophysiological studies of the same individuals. The experiments were p e r f o r m e d with Rana esculenta, since certain features of the biology of these frogs make them m o r e convenient subjects for such investigation than Rana t e m p o r a r i a . The optic nerve of a narcotized animal was sectioned in a cavity in the skull at the chiasm. After 3-5 days, unilaterally operated animals were placed in a pond; bilaterals were put in a drainless pond, where they lived for s e v e r a l months. P e r i o d i c a l l y , the animals' behaL a b o r a t o r y of Comparative Vertebrate Neurophysiology, A. N. Severtsov Institute of Evolutionary Morphology and Ecology of Animals, A c a d e m y of Sciences of the USSR, Moscow. T r a n s l a t e d from Zhurnal l~volyutsionnoi Biokhimii i Fiziologii, Vol. 12, No. 5, pp. 489-490, S e p t e m b e r - O c t o b e r , 1976. Original article submitted June 23, 1976.
196
0097-0549/78/0902-0196507.50
9 1979 Plenum Publishing Corporation
Oo
~ OoO12
oa ob
Fig. 1. Sequential r e s t o r a t i o n of retinoc e n t r a l connections during regeneration. I. Schematic figure of the frog brain; a r r o w s : three groups of optic fibers n e c e s s a r y for organization of three f o r m s of behavior; II. Tectal projection of r e t inal ganglion cells of Class HI (a), and Classes I and ]7 (b), 16-20 days (1), 55-60 days (2), and 90-100 days after operation (3).
vioral responses were tested by presenting them with dark targets (spheres 5-130 mm in diameter) suspended f r o m a long fishing pole [9]. Stimuli were presented to unilaterally operated individuals in the monocular field of vision of the appropriate eye. When interesting behavioral responses appeared, animals were caught, and the intact eye was removed. After more p r e c i s e study of these f r o g s ' r e s p o n s e s , they were studied electrophysiologically in an acute experiment. The activity of the regenerating retino-tectal fibers was studied by means of the usual methods, using platinized m i c r o e l e c t r o d e s and presenting moving, flat, contrasting visual stimuli [1]. The experiments were p e r f o r m e d on 128 individuals in the s u m m e r s of 1973-1974 at the Institute 's biological station "Deep Lake. " During the r e s t o r a t i o n of the f r o g s ' vision, a c l e a r nonsimultaneity was observed in the appearance of the various f o r m s of visually driven behavior. Sixteen to twenty days after operation, "spontaneous movement" appeared and r e s p o n s e s to avoid obstacles o r jump upon them, as well as leaps into dark and light a p e r tures positioned above the level of the ground. All these responses can be united in one group, since they require the perception of l a r g e , nonmoving objects and the determination of their position in space. Avoidance r e s p o n s e s appeared 55 days after operation, and food-getting responses after 90 days. Electrophysiologieal experiments revealed that both the sequence and the dates of restoration of retinotectal connections of RGC of the various c l a s s e s a r e s i m i l a r in Rana esculenta to those in Rana t e m p o r a r i a [8]. Experiments were p e r f o r m e d on animals in which one o r another form of visually driven behavior had appeared. The basic results a r e presented schematically in Fig. 1. In animals which perceived l a r g e , nonmoving objects (16-20 days after operation), it was not possible to d i s c o v e r RGC t e r m i n a l s in the tectum. Evidently, optic fibers still have not gro~vn back to the rectum at this t i m e , but have already grown back to some other visual center -- possibly, nuclei in the r o s t r a l thalamus. This is consistent with notions regarding the association of such behavioral responses in frogs with visual projections to the indicated nuclei, in which are to be found axon terminals coming from RGC which a r e excitable by an i n c r e a s e in illumination of the receptive field [2, 10]. In frogs in which the avoidance response has been r e s t o r e d , d i s c h a r g e s are r e c o r d e d in the tectum from axon terminals of RGC having large excitatory receptive fields, m o s t l y of Class HI (of 50 units recorded, 43 were of Class III, 5 of Class IV, and 2 of Class I). Generally, the avoidance response was observed only in those individuals in which terminals from Class III RGC had c o v e r e d nearly the entire tectal s u r f a c e , so that the map of the retino-tectal projection [7] was close to normal for this c l a s s . These data a r e consistent with ideas concerning the leading significance of Class III RGC for the formation of the avoidance response [5], but they do not support the ideas of the same authors concerning the participation of Class I RGC in obstacle avoidance and Class IV RGC in the choice of shelter. Terminals of Classes I and IIRGC were p r e s e n t in the tecta of animals exhibiting food-getting r e s p o n s e s , these behavioral r e sponses being initiated from those regions of the retina from which the axons of these RGC had grown back to the tectum and established synaptic connections; the f i r s t food-getting responses were evoked, naturally, in the a n t e r i o r regions of the visual field. It is possible that the difference between the avoidance and food-getting responses (avoidance requires r a t h e r complete retino-tectal projections) is explained by the necessity for major intratectal integration o v e r a significant part of the visual field. In the first days after the appearance of the avoidance and food-getting responses (55-70 days and 90-120 days, respectively), they were evoked by moving stimuli of any size; the responses were perfected in proportion to the degree of perfection of the retinotectal projection. The food-getting responses at f i r s t were manifested by opening the mouth and sticking out the tongue -- independent of the distance to the target. According to the degree of expansion of the projection of Classes i and IIRGC, turning to the t a r g e t appears and, still later, approach (i. e . , determining the distance t o the food object s e e m e d to be the m o s t finely organized part of food-getting behavior).
197
F o r this r e a s o n , in spite of the fact that f r o g s ' reactions to visual stimuli n o r m a l l y a r e d e t e r m i n e d not only by the a n g u l a r d i m e n s i o n s of the objects viewed but a r e c a r r i e d out with due r e g a r d for the distance to them [9], s p e c i a l i z e d "channelling" of the visual information entering the f r o g ' s brain f r o m RGC of p a r t i c u l a r c l a s s e s is n e c e s s a r y f o r organizing c e r t a i n biologically d i v e r s e f o r m s of behavior. F r o m this point of view, one could s p e a k of not one -- o r even two [10] -- visual s y s t e m s , evidently, but of s e v e r a l visual s y s t e m s in anuran amphibians and, p r o b a b l y , in o t h e r l o w e r v e r t e b r a t e s . In the r e t i n o - t e c t a l division, one m a y suppose that there is special significance in the level of distribution of the synaptic contacts f o r m e d by the axons of RGC of a p a r t i c u l a r c l a s s . The s t r a t i f i e d distribution of the t e c t a l t e r m i n a l s of RGC of different c l a s s e s o c c u r s not only in the n o r m a l animal [1,3], but gradually is r e s t o r e d also a f t e r the r e g e n e r a t i o n of retinot e c t a l f i b e r s (according to [11], as well as o u r own observations}. LITERATURE 1. 2, 3.
4. 5. 6. 7. 8. 9. !0. 11.
CITED
H . R . Maturana, J . Y. Lettvin, W. S. MacCulloch, and W. H. P i t t s , J. Gen. P h y s i o l . , 4__33,N o . 6 , P a r t 2, 129 (1960). W.R.A. Muntz, J . N e u r o p h y s i o l . , 2__55, 712 (1962). O . J . G r f / s s e r and U. G r f / s s e r - C o r n e h l s , in: H. Autrum et a l . , Handbook of Sensory Physiology, Vol. VH/3a, Central P r o c e s s i n g of Visual Information, P a r t A. (R. J u n g , e d . ) , S p r i n g e r - - V e r l a g , Berlin (1973), p. 333. D. Schneider, Biol. Z b l . , 7_33, 225 (1954). I . N . P i g a r e v and G. M. Zenkin, Zh. Vyssh. Nervn. D e y a t . , 2_.0.0, 170 (1970). R . W . S p e r r y , J . N e u r o p h y s i o l . , 7 , 57 (1944). R . M . G a z e , The F o r m a t i o n of N e r v e Connections, Acad. P r e s s , New Y o r k (1970). V . M . Vinogradova, V. A. Bastakov, L. N. D ' y a c h k o v a , and Yu. B. Mantefel', Neirofiziologiya, 5, 611 (1973). E . I . Kiseleva and Yu. B. Manteifel'., Zool. Z h . , 5__33,1817 (1974). D. Ingle, Science, !81, 1053 (1973). M . J . Keating and R. M. G a z e , Brain R e s . , 2_~1, 197 (1970).
SOMATOSENSORY L.
S. A l e e v
EVOKED and
Yu.
POTENTIALS P.
IN HEALTHY
PEOPLE UDC 612.825
Varezhkin
The: r e s u l t s of a study of s o m a t o s e n s o r y evoked potentials r e c o r d e d in 37 healthy stlbjects of both s e x e s a r e d e s c r i b e d . C o m p a r i s o n of the r e s u l t s of t e s t s on t h r e e age subgroups showed selectivity in the change in l a t e n e i e s and a m p l i t u d e s of w a v e s of the s o m a t o s e n s o r y r e s p o n s e s depending on the s u b j e c t ' s age. I p s i l a t e r a l r e s p o n s e s show g r e a t e r v a r i a b i l i t y but a l o w e r amplitude and frequency of a p p e a r a n c e of the individual components than c o n t r a l a t e r a l r e s p o n s e s . T h e i r latent p e r i o d s a l s o w e r e longer than those of the c o n t r a l a t e r a l r e s p o n s e s . INTRODUCTION N u m e r o u s investigations of cortical evoked potentials (EPs) in a n i m a l s have shown that the EP method is highly effective as a m e a n s of studying the conducting pathways and connections in the CNS. F o r v a r i o u s r e a s o n s of a technical nature human E P s have r e c e i v e d f a r l e s s study. When deciding to investigate s o m a t o s e n s o r y E P s of the human b r a i n it was r e a l i z e d that information on the c h a r a c t e r and p r o p e r t i e s of t h e s e r e s p o n s e s is scanty and s o m e t i m e s c o n t r a d i c t o r y . T h i s is the c a s e , for e x a m p l e , with the concept of " n o r m a l " as applied to c o n t r a l a t e r a l r e s p o n s e s and the g e n e s i s of i p s i l a t e r a l r e s p o n s e s . Another i n t e r e s t i n g p r o b l e m for study was the possibility of using data on E Ps in clinical neurology f o r diagnostic p u r p o s e s and also for investigating cortical c o m p e n s a t o r y m e c h a n i s m s in the c o u r s e of r e c o v e r y
Institute of C y b e r n e t i c s , A c a d e m y of Sciences of the Ukrainian SSR, Kiev. T r a n s l a t e d f r o m N e i r o f i z i o logiya, Vol. 8, No. 5, pp. 447-454, S e p t e m b e r - O c t o b e r , 1976. Original a r t i c l e submitted N o v e m b e r 6, 1975.
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9 1979 Plenum Publishing Corporation
