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A review of Soviet papers
RUMANIAN GROUP alopathies and in the pseudotumoral forms of multiple sclerosis. The electrical characters of certain neurological syndromes accompanied by raised intracranial pressure of undetermined aetiology (pseudotumoral) were analysed in an attempt to establish electrical criteria of differentiation between the non-tumoral hypertensive syndromes
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studied and tumoral space-occupying processes. Stress is laid on the importance of controlling cerebral oedema by intravenous administration of urea-mannitol. Several distinctive electrical traits of cerebral haematomas with raised intracranial pressure and tumours imitating cerebral vascular accidents are pointed out.
Electroenceph. clin. Neurophysiol., 1967, 22:567-579
A REVIEW OF SOVIET PAPERS Published in the second half of 1965 D . K . KAMBAROVA
Institute of Experimental Medicine, Academy of Medical Sciences, Leningrad (U.S.S.R.)
[Evoked potentials in n.ruber and traetus tegmentalis centralis of a eat after stimulation of nervus splanchnicus.] V. Yu. Ermolaeva and V. N. Tchernigovsky. - Byull. eksp. Biol. Med., 1965,7: 3-6. Having employed evoked potentials the authors made an attempt to find out the significance of n.ruber in transmitting visceral impulses, to study the pathways bringing these impulses and to establish the functional role of cortex-n.ruber connections. The evoked potentials were recorded from unipolar derivations. Positive-negative responses arise in n.ruber during stimulation of nervus splanchnicus, their latency being 10-16 msec, positive amplitude 40-50 pV, negative 80-100 t~V, the positive phase duration being 10-20 msec, the negative 20-30 msec. During somatic stimulation the latency was somewhat shorter, particularly on the same side. The phase durations were the same, the amplitude was somewhat larger. The frequency of evoked responses occurring in n.ruber during somatic and visceral stimulation was less than that in cortex. Electrophysiological study of tractus tegmentalis centralis was carried out at the levels where transmitting systems contact directly with the dorsal surface of n.ruber. In tractus tegmentalis centralis the same kind of stimulation evoked negative-positive responses with quite different characteristics. Having compared these results with some anatomical data the authors presume that visceral and somatic afferent impulses arrive at the n.ruber via the olivo-spinal tract and ascending reticular fibers of the central pathway of Bechterev's tegmentum. These visceral and somatic projections converge both in n.ruber and inferior olive. The functional significance ofcortex-n.ruber connections starting from the afferent zones of nervus splanchnicus was studied both before and after transection of the white matter under these cortical zones. The resulting longer latency of the evoked responses suggested some facilitating influence of the sensory regions of the visceral cortex on the transmission of afferent visceral and somatic impulses into n.ruber.
2.
[Changes in hypothalamic e|ectrical activity after sciatic stimulation and adrenalin administration.] A. V. Tonkikh, A. I. Ilyina and S. I. Teplov. - - Fiziol. Zh., 1965, 6: 754-761. An attempt was made to find out how much the torte of higher autonomic centers depends upon the peripheral afferent impulses. 36 experiments were performed in cats under chloralose anesthesia. In 20 experiments 0.3 ml of 0.1% adrenalin solution was administered intravenously, in 10 experiments the sciatic nerve was stimulated and 6 were control experiments. Electrodes were inserted into the anterior and posterior parts of the hypothalamus. The EEG records were bipolar. In cats sciatic stimulation and intravenous adrenalin administration activated the ~lectrical events in both parts of the hypothalamus (EEG desynchronization, increased amplitudes). This coincided with hypertension, though sometimes the blood pressure might fall. Besides the early EEG changes after sciatic stimulation or adrenalin administration in most experiments long-term activation (1.5-3.0 h) of anterior and posterior hypothalamic activity was observed. This coincided with the second prolonged wave Of hypertension described elsewhere. The activation of hypothalamic electrical events is regarded as indicating excitation of the autonomic centers at various points of the neuro-hormonal chain, a reaction evoked either by adrenalin or sciatic stimulation. 3.
[Some infliees of a slow controlling brain system.] N. A. A l a d j a l o v a . - Biofizika, 1965, 6: 1076-1082. The controlling systems in living organisms may be divided into fast and slow. The author describes in detail the slow controlling system (SCS). Interaction of the fast and slow systems is mentioned. The slow one is supposed to organize a program for interaction of the elements of the fast system. The described system is associated with some definite anatomical structures: hypothalamic system, hippocampus and amygdala. The reticular system is associated w~th the fast system.
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The author indicates 3 stages in the controlling process: (1) in the alert state the stage of multiple involvement of brain structures in response to some new systematic or excessive excitation; (2) determination of the optimum nuclear interaction within the fast system and searching for the optimum minimum of functional connections between elements; (3) fixation of the determined narrow channel of functional connections within the fast system. The SCS switches on its mechanisms in the first stage, actively works in the second and gives up controlling in the third. To analyse the SCS functions the author employs 4 indices: (1) " h o u r oscillations" of activity, (2) "infra-slow" rhythms, (3) "wandering" bursts of activity, (4) assimilation by some nuclei of signals coming to the other nuclei. All these phenomena and their characteristics are described in detail. Changes in hour oscillations, infra-slow rhythms and wandering bursts of activity were studied in rabbits during elaboration of conditioned defense responses. The SCS provides adaptation of an organism and is supposed to relate to one of the higher controlling levels. It controls the interaction between fast independent systems and the dissonances occurring within the fast systems are its trigger. Such dissonances occur at disarrangements of reasonable brain work or at emotional disturbanees. The SCS influences every level of the control: level of interaction between parts of a neuron, between separate neurons, between brain nuclei and structures. The SCS is supposed to aid to form definite ideas concerning the rules of development of trace processes in brain control activity, which are separated by many hours from a stimulus. 4.
[Cortical single unit activity during ascending influences of varied biological significance.] Yu. A. Fadeev. Fiziol. Zh., 1965, 10: 1 1 6 9 - 1 1 7 6 .
An attempt was made to find out some peculiarities of single neuron activity in forebrain cortex under conditions of ascending activating influences of varied biological significance. Special attention was paid to the possibility of convergence on the same neuron of different ascending activating influences. In experiments in 27 hungry cats 162 neurons were studied. A single electrical stimulus was given to the contralateral sciatic nerve. The data obtained indicate that the number of discharging neurons in forebrain cortex of a hungry cat is statistically much greater than that of a cat fed before the experiment. In a hungry animal such neurons after glucose administration reduce their spontaneous firing, sometimes up to complete disappearance of discharge. On the contrary, in a fed animal the poor spontaneous firing practically does not change after glucose administration. The author supposes these facts to indicate that activation of the forebrain cortex in a hungry animal is accounted for by involvement of a g~eat many neurons in the ascending specific feeding excitation. In forebrain cortex the spontaneous firing in a hungry animal is rather inhibited by a single electrical shock to the sciatic nerve, while in a fed animal it is facilitated by the shock. The inhibition of a neuron's activity by a single electrical shock to the sciatic nerve may be regarded as a result of interaction between two different kinds of bio-
logical activation (feeding and defense) arriving at the same single neuron. Such a convergence may be called a "multibiological" convergence (Anokhin 1963). 5.
[Interaction between cerebral cortex and reticular formarion in motor dominant reactions elaborated at different levels of the central nervous system.] M. A. Riabinina. - - Fiziol. Zh., 1965, 10: 1149-1158.
The influence of a cortical focus of stationary excitation, caused by polarization, on a strychnine focus of increased excitability in the reticular formation was studied, and also the reciprocal influence from the reticular formation on the cortical focus of increased excitability. The experiments were performed in rabbits with implanted electrodes. A small direct current applied to the cortex affected in different ways the seizure activity in the reticular formation: anodal current increased it and cathodal suppressed it. An excitation focus caused by strychnine applied to the reticular formation influenced the cortex in two ways: strong focal excitation in the reticular formation immediately after strychnine application inhibited a cortical focus; on the other hand, a weak reticular focus long after strychnine application facilitated the cortical focus. In a rabbit's midbrain reticular formation a mechanism is supposed to exist, able to synchronize the EEG at 4-7 c/see and at slower rhythms (1.5-3.0 c/see). 6.
[Effects of urea on the EEG in patients with brain tumors.] V. L. Dansker, Yu. V. Dubikaitis and T. S. S t e p a n o v a . - Vop. Nel~rokhir., 1965, 6: 27-29.
In 15 patients with brain tumors and cerebral hypertension the cerebral electrical activity was studied after administration of a urea preparation. Average reference derivation was used. The EEG was recorded before and during administration of the drug at 5-10 min intervals. Heart rate, breathing and spinal fluid pressure were recorded simultaneously. E E G changes were both diffuse and local. The diffuse included general EEG improvement, decreased amplitudes, improvement of the background activity, domination of fast rhythms, bursts of synchronized polymorphous activity. Such an effect was noticed mostly in patients with posterior fossa pathology, i.e., in patients with brain-stern involvement. The local EEG changes included either lessening or, on the contrary, increase of the focal slow activity. Such different effects could be seen even in the same patient. The urea preparation is supposed to lessen cerebral hypertension, hence the E E G changes. The degree of the effect depends upon the amount of the drug and the speed of its administration. 7.
[Recruiting response in cats.] A. Roithak and N. Eristavi. - - Zh. vyssh, nerv. Deyat. Pavlova, 1965, 6: 1014-1025.
The experiments were performed on 7 cats with electrodes implanted both into the cortex and subcortical structures. Stimulating electrodes were inserted into the thalamic nonspecific system - - centro-medial or reticular nucleus. The recruiting response evoked by stimulation of the nonspecific thalamic nucleus was characterized by inconsistency of its potential amplitude, its development, its spread over the cortex, etc. "Spreading" and "concentration" of
Electroenceph. clin. Neurophysiol., 1967, 22:579-586
SOVIET PAPERS the response were observed. The recruiting response was regularly observed in the midbrain reticular formation. 6-10/see stimuli applied to the non-specific thalamic nucleus evoked a pronounced recruiting response of 2-3 see duration. The recruiting response was associated with drowsiness and suppression of motor activity, which were more pronounced with stimulation of the reticular or central medial nucleus. 8.
[Interconnection between spike discharges and evoked potentials in rabbit's visual cortex.] V. B. Poliansky. - Zh. vyssh, nerv. Deyat. Pavlova, 1965, 5: 903-910.
The correlation between slow waves and single unit discharges evoked by light stimulation in the rabbit's visual cortex was studied with monopolar leads. Quite a significant correlation was revealed between inhibition of spike discharges in the visual cortex and the large slow positive wave evoked by the light stimulation. Phases of recurring fast and slow unit potentials in the visual cortex during light stimulation are described. It is shown that alternating phases of excitation and inhibition of spike discharges in the rabbit's visual cortex during light stimulation correspond in time sequence with those in the cat's visual cortex and, according to some published reports, to the phases of subjective after-images in man. 9.
[Evoked potentials in response to electrical skin stimulation in patients with EEG focal pathology.] A. A. Sokolova. - - Zh. vyssh, nerv. Deyat. Pavlova, 1965, 5: 878-885.
Fifteen normal subjects and 25 patients with marked EEG focal pathology were studied. The most regular and marked component of the E E G response to electrical skin stimulation proved to be a potential of"non-specific response" type, in normal subjects recorded mainly from posteriorfrontal leads bilaterally and symmetrically. Occasionally the evoked potentials were asymmetrical, predominantly contralateral. In patients with focal E E G pathology the evoked potential was significantly greater in amplitude on the affected side. It was most pronounced in a region adjacent to the pathological focus. The studies of evoked potentials in response to various afferent stimuli in patients with local brain lesions show that the region of the pathological E E G focus possesses some features characteristic of a focus of dominant excitation. 10. [Participation of M-cholinergie systems in the mechanism of Aminazine (chlorpromazine) central effect.] R. Yu. Iliutehenok and R. B. Matveeva. - - Farmakol. i Toksikol., 1965, 6: 643-646. This study was carried out in 110 cats and rabbits with intact brains and with transections of the brain-stem at various levels, as well as in rabbits with electrodes implanted in the non-specific thalamic nuclei and mesencephalic reticular formation. Interaction of aminazine and drugs exciting mainly central M- and N-cholinergic structures (arecoline, nicotine) and suppressing acetylcholinesterase (galanthamine, eserine), was studied. Analysis of the data obtained showed that the Aminazine effect on the central nervous system, besides blocking adrenergic systems, also represented suppression of M-cholinergic
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systems of the reticular formation (blocking of reticulocortical activity evoked by galanthamine and eserine and blocking of the arecoline M-cholinolytic effect). However, it was noticed that the cholinolytic effect of Aminazine is much shorter and weaker than that of the central cholinolytics. The eholinolytic effect of Aminazine is supposed to be associated with blocking of both M-cholinergic neurons of the brain-stem reticular formation and M-cholinergic structures in more rostral parts of the brain. 11. [Some morphological-physiological bases of the rational reactions of the so-called non-specific brain structures. ] R. A. Durinian and A. G. Robin. - - In: "Sovremennie problemy fiziologii i patologii nervnoi sistemy" ["Contemporary problems of physiology and pathology of the nervous system"], Moscow, 1965: 256-273. The authors share the contemporary belief in the reticular formation as a heterogenic multifunctional structure. A mechanism is supposed to exist, able to carry out a primary analysis and to select the most important information arriving at the central nervous system (particularly at the reticular structures) simultaneously by different channels. Hence the authors assume that selection of the information must be carried out in every sensory system already. To solve these problems the distribution of afferent projections and types of responses in the midbrain reticular formation and the nuclei of the diffuse thalamic system were studied. A thorough electrophysiological investigation of n. centrum medianum revealed some regions connected mainly with afferent projections of the nerve studied. In the authors' opinion the data testify to the relative spatial distribution of afferent projections in n. centrum medianum. As in n. ventralis posterior, the front parts of the body project to the ventro-medial parts of the nucleus and conversely, near the rostral pole. Such a topography is considered to reflect the existence in transmitting systems of a distribution of afferent projections of various nerves. In the authors' opinion the relatively local somatotopically organized zones of representation of various afferent systems in n. centrum medianum may be regarded as sources of still more local projections to the cortex and, consequently, of less diffuse reactions, evoked by excitation of neurons of the nucleus itself. Studies of the cortico-reticular influences showed also that in the brain-stem and thalamic reticular structures the potentials with the largest amplitudes are evoked by stimulation of some definite areas of the somato-sensory cortex, i.e. foci of maximal activity of the somato-sensory areas 2 and 1. Such a dependence is accounted for by the cortico-reticular influences arising mainly from those cortical areas which first receive the information via specific transmitting systems. Experiments with local cooling of the cortical projection areas were performed in order to study the spread of cortical influences coming to the reticular structures from the projection areas of the somatosensory cortex. Alternatively, somato-sensory areas 1 and 2 were cooled and the evoked potentials were recorded in these areas and in the midbrain reticular formation or medial thalamic nuclei, during stimulation of the thalamic relay nucleus. Only the somato-sensory cortical area 2
Electroenceph. clin. Neurophysiol., 1967, 22:579-586
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proved to provide close contact with the reticular structures. Some data were also obtained showing the importance of somato-sensory area 2 for the control of nonspecific thalamic activity. When studying the evoked action potentials of single neurons of the reticular structures during cooling of the cortex, data were obtained leading to the conclusion that every afferent system possesses its own cortical control of reticular activity evoked by impulses arriving by this same system. Some assumptions are made concerning the functional significance of the twofold representation of the sensory systems in the cortex. Discussing their own data and those of Andersson (1962), Carreras and Andersson (1963), Carreras and Levitt (1959), Kaada and Johannessen (1960), Segundo et aL (1955)etc., the authors presume that somato-sensory cortical area 2 does not directly participate in the delicate discriminative analysis of information but controls the activity of neurons of non-specific thalamic and brainstem structures which is associated with afferent impulses coming to these structures from the somatic and visceral systems. The authors believe that there is a sound basis nowadays for rejecting the hypothesis of the non-specific character of these structures, the absence of qualitative specific excitation in them and, consequently, to reject the very term "non-specific systems". It would be more correct to call the medial thalamic nuclei, and n. centrum medianum in particular, "secondary relay systems". 12. [Cortical electrical activity after destraction of the thalamie specific (relay) nuclei.] E . S . Moniava and R. K. Borukaev. - - Zh. vyssh, nerv. Deyat. Pavlova, 1965, 6: 1047-1054. The study is dedicated to problems concerning the significance of thalamic specific nuclei for spontaneous cortical electrical activity (EEG), E E G changes caused by lesions of different thalamic relay nuclei and the significance of these lesions for the development of recruiting responses and spontaneous spindle bursts in corresponding cortical projection areas. The experiments were carried out in cats with intact nervous systems, either immobilized with succinylcholine chloride or under Nembutal anesthesia. The results revealed that electrical lesions of the thalamic relay nuclei cause slow waves or even regular spindle bursts in corresponding cortical areas. Recruiting responses evoked by stimulation of the thalamic non-specific nuclei increase markedly after the relay thalamic nucleus has been affected, and their amplitude becomes more pronounced in the cortical area corresponding with the affected nucleus. A cortical projection area in which slow waves arise after lesion of a specific relay nucleus proves to be less affected by the desynchronizing influence of the mesencephalic reticular formation than other areas. 13. [Spread of evoked potentials over the cat's cortex during fight stimulation.] E. L. Shulga. - - Fiziul. Zh., 1965, 10: 1 1 8 2 - 1 1 8 7 . The connection between cortical projection areas and primary response spread was studied. Some cortical areas were surgically isolated from the rest of the cortex and
undercut from the lower structures. Primary responses were studied before and 2-3 days after surgery. The known latencies of visual evoked potentials all over the area from occipital to frontal pole were confirmed as being 10-15 msec. The latency regularly increased for 2-6 msec if measured from fronto-parietal to frontal areas. It hardly changed in occipital and posterior parietal areas. It is shown that circular subpial isolation of the forebrain cortex abolishes the positive phase of the evoked response or diminishes the probability of responses occurring in the isolated area. Undercutting of the cortex practically does not change the spread of the visual evoked responses in the undercut areas. In the author's opinion these results confirm his former statement concerning the genuine cortical spread of processes reflected in the visual primary cortical response. Also these results give grounds for the hypothesis of dynamic interaction between an excited focus in a projection area and processes spreading over the cortex. 14. [Heterogenic delta waves in anoxia and the postanoxie state.] A . M . Gurvitch. - - Fiziul. Zh., 1965, 10: 1 2 1 0 - 1 2 1 9 . Electrodes were inserted into the deep brain structures and placed on the dura mater of 23 dogs. Cerebral activity was studied during dying and reanimation. 59 cases of dying and 39 of reanimation were observed. Death was caused by bleeding and alternating current heart effects, reanimation was by arterial blood pumping, adrenalin administration and artificial respiration. The author discovered two types of delta waves occurring in death and during and following reanimation after complete cessation of circulation for about 0-12 min: (1) polymorphous delta waves, asynchronous in different cortical areas and subcortical nuclei; (2) standard negative-positive slow complexes, widespread throughout the cerebral hemispheres and synchronous in different areas. The polymorphous delta waves are supposed to occur as the result of cortical excitation, which is confirmed by their connection with evoked potentials of the primary response type and their being followed by local bursts of fast waves. The standard slow complexes have their own subcortical pace-maker and the cortex has nothing to do with them. Their spread all over the brain is determined both by physiological rules and the rules of potential spread in a volume conductor. The author states that, because of synchronization of the standard slow complexes in different cortical areas, they should be recorded with monopolar leads. 15. [Some means and principles of neurophysiulogical analysis of human deep cerebral structures.] N . P . Bechtereva. - - I n : "'Sovremennie problemy fiziologii i patologii nervnoi sistemy" ["Contemporary problems of physiology and pathology of the nervous system"], Moscow, 1965: 274-291. Electrophysiological study of human deep cerebral structures may be successfully carried out by means of various methods, particularly that of implanted electrodes. E E G studies under conditions of selective pharmacological influence on adrenergic and cholinergic systems provide the possibility to determine more exactly the area and Electroenceph. clin. Neurophysiol., 1967, 22:579-586
SOVIET PAPERS character of cerebral pathology and also to understand more completely some mechanisms of the so-called spontaneous (background) cerebral activity. For instance, the polymorphous pathological EEG was shown to be associated with hyperactivity of some functional systems and suppression of others, etc. Subcorticographic and EEG changes during stimulation of various deep structures via the implanted electrodes allow investigation of the interaction between deep structures arid correlation between electrical events and neurological, psychological and some other reactions.
16. [Interhemispherie relations in dogs with split brains.] V. M. Mosidze and N. B. Sheresheva. - - Zh. vyssh. nerv. Deyat. Pavlova, 1965, 6: 977-981. Animals with split brains (i.e., with all the commissures cut - corpus callosum, anterior and posterior hippocampal commissures, massa intermedia) were studied. The possibility of transferring auditory information from one hemisphere to the other and the formation of intcrhemispheric temporary connections was studied. Two chronic experiments on motor defense responses were carded out on 2 normal dogs and 2 dogs with split brains. In the normal animals the auditory information during conditioning to a sound proved to be transferred to the opposite hemisphere and fixed there. In the dogs with split brains the authors failed to observe any transference of the auditory information from one hemisphere to the other. The conditioned response formed in one hemisphere seemed to stick to it. However, a temporary interhemispheric connection could still be formed provided the excitation of both conditioned and unconditioned centers, situated in different hemispheres, was associated in time. The experiments also showed that ipsilateral auditory afferent fibers, during stimulation of only one ear, do not participate in forming the temporary connection. Midbrain structures and some other deep areas are supposed to account for the realization of the intcrhcmispheric connection.
17. [The effect of reticular impulses on single unit activity in the visual cortex.] S. P. Narikashvili, V. S. Arutiunov and E. S. Moniava. - - Zh. vyssh, nerv. Deyat. Pavlova, 1965, 6: 1 0 0 4 - 1 0 1 3 . Some peculiarities of the effect of reticular impulses on the single unit activity in the visual cortex were studied and an attempt was made to find with what characteristics of unit potentials a reticular effect is associated. All the experiments were carried out on encdphale isol~ cats. The experiments showed that reticular influences on the "spontaneous" activity of some neurons of the visual cortex are facilitating and on others inhibiting. In most cases the facilitating effect was observed in neurons that reacted to flashes. Neurons inhibited by flashes were also inhibited by reticular impulses. Under some definite conditions one or another type of reticular influence was predetermined by the frequency of firing of the neuron. The facihtatmg or inhibiting reticular effect on the neuron's response was less dependent on its type of response to light stimulation. Problems of the dependence of the character
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of a reticular effect on the type of response of a cortical neuron to light stimulation, conditions for changes in a neuron's reaction type in the visual cortex and the lack of correlation between surface response and neuronal discharge during reticular stimulation, txeitisoussed.
18. [Electrophysiological data c o n c e r n i ~ the interaction between cortex and caudate nucleust ] S . M . Butichusi. Zh. vyssh, nerv. Deyat. Pavlova, 1965, 6: 1 0 3 6 1045. Experiments were carried out on cats immobilized with alpha-tubocurarine or Lysthenon, and on enc~phale isold preparations with the spinal cord cut at the 2nd cervical segment. Identification of depth electrode placements was done according to Jasper and Ajmone-Marsan's Atlas. When a single stimulus was applied to the caudate nucleus in intact cats a spindle burst of slow waves was observed in the cortex and some deep structures: both caudate nuclei, mesial, medial and ventral anterior thalamic nuclei, hypothalamus and the midbrain reticular formation. These spindle bursts increased after transection of the medial part of the brain-stem near the anterior corpora quadrigemina. This reaction gradually decreased with further transections near the mesial-medial and central lateral nuclei and altogether disappeared after transection of the medial part of the thalamus near the ventralanterior nucleus. On fast stimulation of the caudate nucleus (50-200/see) suppression of thalamo-cortical responses in the sensory cortex and facilitation of responses in the visual cortex occurred. After an electrical lesion of the midbrain reticular formation the fast stimulation of the caudate nucleus no longer facilitated responses in the visual cortex but still suppressed the responses of the sensori-motor cortex. After short tetanization of the sensori-motor cortex (2-3 sec) neuronal discharges in the caudate nucleus evoked by stimulation of the contralateral forepaw were facilitated. During an after-discharge evoked by tetanization of the sensorimotor cortex (5-7 sec) every burst of clonic waves in the cortex caused cellular discharges in the caudate nucleus.
19. [Slow shifts of cortical potential during stimulation of medial thalamic nuclei.] Z. P. Shuranova. - - Zh. vyssh, nerv. Deyat. Pavlova, 1965, 4: 705-710. Experiments were carried out on 15 rabbits immobilized by Diplazine or tubocurarine. Electrical activity was recorded with calomel electrodes connected with a cotton wick (for electrocorticography) or a capillary through a salt solution. The results revealed dissimilarity of cortical responses to stimulatmn of medial thalamus. First, an essential difference between responses to low and high frequency stimulation of the thalamlc structures was discovered. At the low frequency a local surface negative shift of the cortical potential was observed, which either could not be found in deeper layers or had an inverse polarity there. At the high frequency either a diffuse shift of cortical potential was observed or it was more pronounced in the deep cortical layers and absent or positive
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on the surface. This surface negative shift of the cortical potential is supposed to reflect a stable depolarization of elements of the surface cortical layers. It was also shown that high frequency stimulation of the medial thalamus was accompanied by two variants of slow shifts of the cortical potential differing from one another in duration, vertical distribution of the negative component, connection with different cortical rhythms and different sensitivity to Nembutal. From the results obtained the author singles out the first type of reaction ("thalamic") and the second ("reticular"). It is assumed that the character of the cortical response to stimulation of the medial thalamus depends essentially upon the functional state of the animal. Against a relatively inhibited background, when stimulation is not followed by excitation of the brainstem reticular formation, a response of the first type occurs, whereas against a more activated background that of the second type occurs. 20. [Spontaneous discharges of the neurons of the somatosensory cortex and peculiarities of their functional organization.] N. N. Vassilevsky. - - Fiziol. Zh., 1965, 6: 710-716.
In this study the author tries to find out how the peculiarities of organization of cortical neurons affect the level and character of their background activity. Two series of experiments were carried out on cats and rabbits immobilized by Procuran or Lysthenon. A surface monopolar electrocorticogram was made, with recording of unit potentials. Receptive fields were determined for every neuron under study. Spontaneous firing of different functional types of neurons of the somato-sensory cortex has three main forms: single discharges, bursts and groups of discharges. All three forms are described in detail and an assumption is made that these variants of spontaneous firing are predetermined by time and amplitude peculiarities of depolarizing processes in the neuron soma. Further, it is noticed that, in cats, fast activity in the somatosensory area corresponds with frequent spontaneous firing. It is also shown that in cat's and rabbit's somato-sensory cortex different functional types of neurons have different levels of spontaneous firing. The highest spontaneous firing rate was observed in non-specific neurons (28.2+ 2.2 and 13.3 :L 2.0/sec in cats and rabbits respectively) and the least rate in non-activating them (8.9 ± 2.3 and 6 . 6 ± 1.2/sec). Middle values were characteristic of specific neurons. In the author's opinion the difference in spontaneous firing of neurons in the somato-sensory cortex of cats and rabbits is reflected in their subcortical rhythms. 21. [Cholinesterase and brain waves during eserine and galanthamine effects in animals with pre-mesencephalic transections.] R. Yu. Iliutchenokand L. N. Nesterenko. - - Byull. eksp. Biol. Med., 1965, 10: 57-60.
Experiments were carried out on 37 cats. Cholinesterase activity was determined by Ponosian's photoelectro-colorimetric method. The E E G was recorded with steel needlet inserted into the skull. The brain-stem was transected jus
~aefore anterior corpora quadrigemina above and after corpora quadrigemina below (pre-mesencephalic transection) and between anterior and posterior corpora quadrigemina (Bremer's cerveau isold). In pre-mesertcephalic transection cholinesterase activity in the brain after galanthamine is suppressed everywhere as in intact animals. E E G activation could not be revealed in spite of the nearly complete cholinesterase suppression in pretransection areas (in diencephalic area up to 10.7-16.9 % of normal, in the cortex, 0.03 %). Comparison of the cholinesterase effects in cerveau isold and intact animals revealed that even two or three times smaller doses of galanthamine and eserine suppressed the effect and activated the EEG. Consequently the cholinesterase E E G activation depends upon suppression in the mesencephalic areas. 22. [Neurochemical mechanisms of ascending cortical activation in hungry animals.] K . V . Sudakov and A. I. Turenko. - - Byull. eksp. Biol. Med., 1965, 10: 3-7. Cholinergic mechanisms maintaining cortical activation in hungry animals were studied. Experiments were carried out on 40 cats under urethane anesthesia after 24 h of food deprivation. Scalp EEGs and etectrocorticograms were recorded. In hunger a selective EEG activation in the forebrain cortex appeared, while in posterior areas high voltage slow waves characteristic of sleep were seen. Cholinolytics (atropine, Amizil) usually caused high voltage slow waves in the forebrain areas of hungry animals. Application of the drugs to the cortex abolished the activation in the forebrain cortex and had no effect on pain EEG activation. It is concluded that cholinolytics block the mechanisms of feeding adaptation. In order to study neurochemical mechanisms of cortical synapses, we investigated evoked potentials caused by sciatic stimulation during hunger activation of the forebrain cortex and after abolishing the activation with cholinolytics. The experiments showed quite distinct chemical peculiarities in the cortical axo-dendritic synapses during the different biological reactions. Some chemical peculiarities during different biological reactions are supposed to be intrinsic to subcortical structures, 23. [Nivalin and Amizil effects on the EEG and alerting response in man.] T . P . lsakova. - - Zh. vyssh, nerv. Deyat. Pavlova, 1965, 6: 1113-1121.
Himwich and Rinaldi (1955, 1957), Longo and Silvestrini (1957), Iltchenok and Mashkovsky (1961) and others showed that acetylcholine and its derivatives, as well as some anticholinesterase drugs of the physostigmine type (eserine, galanthamine, Nivalin) caused the same EEG activation as any afferent stimulation, while cholinolytic drugs (atropine, Amizil and others) are known to exert the contrary effects. Anitchkov and Denisenko (1962) singled out these drugs as a special group of central cholinolytics because of their ability to block mainly interneuronal cholinergic structures in the central nervous system while having relatively weak peripheral seffects. Art attempt was made to find out how Nivalin (inElectroenceph. clin. Neurophysiol., 1967, 22:579-586
SOVIET PAPERS creasing sensitivity of brain cells to acetylcholine) and Amizil (suppressing the cerebral cholinergic structures) affect different components of the alerting response in healthy men and patients with paranoid schizophrenia. Nivalin was tested in 15 healthy men and 21 patients, Amizil in 20 healthy men and 22 patients. Nivalin increased the amplitude of the alpha rhythm and made it more regular and improved bioelectric, autonomic and motor components of the alerting response both in healthy and diseased men. After Amizil gradual decrease of the alpha amplitude and replacement of the rhythm by low voltage slow waves were observed both in healthy and diseased men. Under Amizil stimuli evoked increase of the alpha rhythm all over the cortex. The cholinergic structures are supposed to participate in the genesis of the h u m a n alpha rhythm. 24. [Significance of serotonin for central nervous system activity.] E. A. Gromova. - - In: "So~Temennie problemy fiziologii i patologii nervnoi sistemy" ["Contemporary problems of physiology and pathology of the nervous system"[, Moscow, 1965: 346-357.
Some biologically active drugs are essential for complicated processes of neuro-humoral control of the organism's functions. Serotonin is quite important amongst these drugs. High concentrations of serotonin in some cerebral structures, high effectiveness of the drug on cerebral functions etc. make the assumption of serotonin as a mediator quite reasonable. However, there are many contradictory reports concerning the role of serotonin in the central nervous system. Effects of serotonin on spontaneous cerebral electrical activity and evoked potentials, on the excitability of some cerebral structures and segmental reflex processes in the spinal cord, were studied in rabbits with implanted electrodes. In discussing the data obtained the author indicates the serotonin effect on the functional state of different parts of the central nervous system. A biphasic serotonin effect with a prevailing second prolonged activating phase is shown. A primary serotonin effect on the subcortical activating structures is supposed. A n observed serotonin effect on the hypothalamus allowed the assumption that serotonin-induced changes in it participate in the mechanisms of circulatory control. 25. [Electrophysiological data concerning the role of the cerebral cortex in the genesis of oxygen seizure.] I. B. Voronov. - - Fiziol. Zh., 1965, 7: 777-783.
In 41 experiments on cats changes of cerebral cortical spontaneous activity caused by high oxygen pressure were studied in intact brain and cerveau isold preparations. In cats with intact brains one of the first signs of the high oxygen pressure effect is E E G desynchronization. During oxygen seizures high voltage "hypersynchronized" discharges are observed in the EEG. After separation of the forebrain areas from the lower parts (cerveau isold) the oxygen seizure does not appear in cats. Also the E E G changes characteristic of high oxygen pressure are absent. In the cerveau isold even after long-lasting high oxygen pressure the ordinary sensitivity of the forebrain to the effects of corazol, eserine, arecoline, atropine and dipha-
585
sine are preserved (eserine and arecoline are drugs with cholinomimetic effects; atropine and diphasine are cholinolytics usually restoring sleep spindles). The forebrain is not the most sensitive part of the brain to the toxic effect of oxygen. Presumably the midbrain reticular formation is the starting link in the oxygen intoxication. 26. [Electrophysiological study of some human deep structures with implanted electrodes. ] T . G . Urmantcheeva and N. I. Diakonova. - - Fiziol. Zh., 1965, 8: 909-917.
Electrical activity of ventro-lateral thalamic nuclei and globus pallidus was studied in 5 patients operated on because of various hyperkinesias. From 6 to 12 electrodes were implanted in each patient. The subcortical electrical activity was characterized mainly by waves at 4-6 c/sec but 2-3, 8-12 and 18-24 c/sec waves were also observed. The amplitudes of the waves varied from 25 to 70/~V. Contralateral motor responses were observed during stimulation of globus pallidus and the ventro-lateral thalamic nucleus: blinking, winking, making fists, head turning, contraction of mimic, shoulder and spinal muscles. Some changes in the electrical activity of the subcortical structures were also observed: in the stimulated and adjacent areas amplitude changes and sometimes slow waves appeared. After stimulation of th~ ventro-lateral thalamic nucleus, with increasing tremor in the contralateral hand, amplitudes decreased in the subcortical structures. Stimulation of the globus pallidus, giving no apparent changes in the patient's motor behavior, was accompanied by high voltage slow waves in this structure and flattening of electrical activity in the ventro-lateral thalamic nucleus. These stimulation-induced electrical changes were quite short. Severe electrical changes were observed in subcortical structures after stimuli followed by complicated sensations and autonomic responses. In one patient after stimulation of the deepest area of the ventro-lateral thalamic nucleus, which evoked sensations of flicker in the eyes, coldness in the stomach and nausea, a pronounced electrical activity (9-10, 12-14 c/sec waves of 200-300 #V amplitude) was observed in the deep structures. During such a subcortical activity amplitudes of the occipital E E G increased and regular 14 c/sec waves appeared in the frontal EEG. The authors presume that motor responses and subjective sensations evoked by stimulation of the globus pallidus and ventro-lateral thalamic nucleus are accompanied by corresponding changes in electrical activity of these structures and in the E E G patterns. 27. [Role of dendrites in mechanisms of signal detection.] N. A. Aladjalova. - - Zh. vyssh, nerv. Deyat. Pavlova, 1965, 6: 1088-1097.
A n attempt was made to find a principle underlying comparison of signals converging on a neuron with formerly established criteria. The author studies the principle of functional organization of synapses in a system and gives a particular example of its realization; further, experimental data concerning some properties of dendrites supporting the discussed principle in a real neuron are considered. Electroenceph. clin. Neurophysiol., 1967, 22:579-586
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The author concludes that the model principle of signal detection consists in transforming the distribution of the model elements from haphazard to regular. The regular condition is formed by the information flow itself, which establishes correlations between distribution of impulses in a signal and distribution of elements by conditions; in case of correlation the summed response of the model overcomes the noise level. The distribution is based on comparison of impulse sequence and intervals in synapses. The model principle may be realized in a dendritic device of signal detection containing axons and a dendrite with its synaptic apparatus in a bifurcation area. The principle requires, on the one hand, a one-step inflow of impulses and signal intervals to the dendritic synapses and, on the other, a coincidence of pre-synaptic and postsynaptic excitation in those synapses, the condition of which must change. It is possible because of the contrary spread of impulses along the dendrite from the bifurcation. Experiments on the axe-dendritic cortical strip of a rabbit's brain show two spike potentials in response to the first stimulus (pre-synaptic and post-synaptic) while, with repeated stimuli (up to 6 times), a post-synaptic slow negative wave is gradually formed reflecting, presumably, the gradual formation of a dendritic response parallel to the growth of correlation between synapse distribution by conditions. During short-term retention of traces local shifts on the neuroglial interface play a certain role. The princible shares the standpoint that specific information storage is determined by internal connections in the neuronal groups. The model of signal detection in dendrites makes it possible to transfer from studying single synapses to studying the whole organization of synapses in functional systems. 28. [A physiological mechanism for the spread of nervous processes over the cerebral cortex.] A . B . Kogan. Zh. vyssh, nerv. Deyat. Pavlova, 1965, 6: 963-969. Basic items of the physiology of higher nervous activity (spread of excitation and inhibition) are discussed in detail. The nature of the spread was thoroughly investigated with indices of background electrical activity, evoked potentials, changes in excitability and conditioned responses. In experiments with undercut cortex desynchronization evoked by flashes, sounds and other stimuli was seen, spreading over the undercut cortex with no ascending activating influences. Desynchronization in the undercut cortex differed from that in intact cortex. In the author's opinion this difference was accounted for by the activating influence of ascending reticular pathways; the ability for active transmission of the nervous processes inherent in the cortex may be increased and altered by ascending influences. In another series of experiments a possible mutual influence of one cortical area over the excitability of another, without direct participation of cortex-subcortical pathways, was discovered (Kogan and Zaguskin 1961). However, abolishing the direct cortico-subcortical interaction sharply changed the influence of one cortical area over others. Unequivocal proofs of a n authentic cortical spread of a conditioned excitation were obtained in experiments with undercutting or circumcutting of cortical
areas. Electrical stimulation of these areas was used as a signal for food conditioned responses (Kogan 1961; Glumov 1962). These experiments showed the transcortical pathways to be more important for realization of the response than cortico-subcortieal connections. In the author's opinion the spreading phenomenon is of a cortical nature and the ascending influences of the reticular system are necessary to maintain a high level of excitability and working ability of the corresponding cortical mechanisms. Tkatchenko and Shulga (1964) studied the spread of visual evoked potentials from occipital to frontal lobes in cats. The mean velocity of spread over the undercut cortical area ranged from 2.0 to 5.0 m/see, which is quite similar to the velocity of 1.5 m/see found by Micld and Edds for the spread of auditory electrical responses. Undercutting did not lessen the velocity of the visual response spread. From the viewpoint of single unit activity successive involvement of the cortical neurons in the response to electrical stimulation of the skin was revealed by differences in the latencies of their action potentials. The time characteristics of this involvement were similar to those of spread of excitation waves (Livanov 1963). Simultaneous recording of action potentials of several neurons showed that they are involved by groups (Kogan and Gorayan 1965), which is why the spread of excitation might have the discrete character of stepped motion of the nervous process. Thus in the author's opinion both the fast processes of neuronal discharges and the slow processes of interaction between functional neuronal groups participate in the spread of nervous processes, as welt as the controlling influences ascending from subcortical structures. These three kinds of process revealed in the investigation of cortical spread represent three levels of its realization, not three possible mechanisms. 29. [Rayaaud's disease. Clinical and pathophysiologieal study of the central nervous mechanisms.] N. P. Bechtereva, A. V. Bondarchuk and V. V. Zontov. - Published by "Medicina", Leningrad, 1965. In the E E G of patients with Raynaud's disease significant polymorphism is a prominent feature: in some cases there is marked prevalence of desynchronization, which may be steady or alternate with bursts of spreading synchronous activity, in other eases there is high synchronization of alpha rhythm or bursts of monomorphous and polymorphous activity of high voltage; sometimes synchronous beta rhythm of low frequency is observed. Trigger and rhythmic photo-stimulation tend to evoke a paradoxical response. The effects of Aminazine, amphetamine and Nivalin on the E E G of patients with Raynaud': syndrome were analysed and disclosed imbalance be tween adrenergic-cholinergic systems. The observed poly morphism of changes in the E E G testifies that in these cases inhibition of one functional system may be accom partied by activation of the other. It is supposed that th. development of Raynaud's disease is mostly determined by dysfunction of non-specific structures of the brainstem and more rostrally located diencephalic formations.
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studied and tumoral space-occupying processes. Stress is laid on the importance of controlling cerebral oedema by intravenous administration of urea-mannitol. Several distinctive electrical traits of cerebral haematomas with raised intracranial pressure and tumours imitating cerebral vascular accidents are pointed out.
Electroenceph. clin. Neurophysiol., 1967, 22:567-579
A REVIEW OF SOVIET PAPERS Published in the second half of 1965 D . K . KAMBAROVA
Institute of Experimental Medicine, Academy of Medical Sciences, Leningrad (U.S.S.R.)
[Evoked potentials in n.ruber and traetus tegmentalis centralis of a eat after stimulation of nervus splanchnicus.] V. Yu. Ermolaeva and V. N. Tchernigovsky. - Byull. eksp. Biol. Med., 1965,7: 3-6. Having employed evoked potentials the authors made an attempt to find out the significance of n.ruber in transmitting visceral impulses, to study the pathways bringing these impulses and to establish the functional role of cortex-n.ruber connections. The evoked potentials were recorded from unipolar derivations. Positive-negative responses arise in n.ruber during stimulation of nervus splanchnicus, their latency being 10-16 msec, positive amplitude 40-50 pV, negative 80-100 t~V, the positive phase duration being 10-20 msec, the negative 20-30 msec. During somatic stimulation the latency was somewhat shorter, particularly on the same side. The phase durations were the same, the amplitude was somewhat larger. The frequency of evoked responses occurring in n.ruber during somatic and visceral stimulation was less than that in cortex. Electrophysiological study of tractus tegmentalis centralis was carried out at the levels where transmitting systems contact directly with the dorsal surface of n.ruber. In tractus tegmentalis centralis the same kind of stimulation evoked negative-positive responses with quite different characteristics. Having compared these results with some anatomical data the authors presume that visceral and somatic afferent impulses arrive at the n.ruber via the olivo-spinal tract and ascending reticular fibers of the central pathway of Bechterev's tegmentum. These visceral and somatic projections converge both in n.ruber and inferior olive. The functional significance ofcortex-n.ruber connections starting from the afferent zones of nervus splanchnicus was studied both before and after transection of the white matter under these cortical zones. The resulting longer latency of the evoked responses suggested some facilitating influence of the sensory regions of the visceral cortex on the transmission of afferent visceral and somatic impulses into n.ruber.
2.
[Changes in hypothalamic e|ectrical activity after sciatic stimulation and adrenalin administration.] A. V. Tonkikh, A. I. Ilyina and S. I. Teplov. - - Fiziol. Zh., 1965, 6: 754-761. An attempt was made to find out how much the torte of higher autonomic centers depends upon the peripheral afferent impulses. 36 experiments were performed in cats under chloralose anesthesia. In 20 experiments 0.3 ml of 0.1% adrenalin solution was administered intravenously, in 10 experiments the sciatic nerve was stimulated and 6 were control experiments. Electrodes were inserted into the anterior and posterior parts of the hypothalamus. The EEG records were bipolar. In cats sciatic stimulation and intravenous adrenalin administration activated the ~lectrical events in both parts of the hypothalamus (EEG desynchronization, increased amplitudes). This coincided with hypertension, though sometimes the blood pressure might fall. Besides the early EEG changes after sciatic stimulation or adrenalin administration in most experiments long-term activation (1.5-3.0 h) of anterior and posterior hypothalamic activity was observed. This coincided with the second prolonged wave Of hypertension described elsewhere. The activation of hypothalamic electrical events is regarded as indicating excitation of the autonomic centers at various points of the neuro-hormonal chain, a reaction evoked either by adrenalin or sciatic stimulation. 3.
[Some infliees of a slow controlling brain system.] N. A. A l a d j a l o v a . - Biofizika, 1965, 6: 1076-1082. The controlling systems in living organisms may be divided into fast and slow. The author describes in detail the slow controlling system (SCS). Interaction of the fast and slow systems is mentioned. The slow one is supposed to organize a program for interaction of the elements of the fast system. The described system is associated with some definite anatomical structures: hypothalamic system, hippocampus and amygdala. The reticular system is associated w~th the fast system.
Electroenceph. clin. Neurophysiol., 1967, 22:579-586
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The author indicates 3 stages in the controlling process: (1) in the alert state the stage of multiple involvement of brain structures in response to some new systematic or excessive excitation; (2) determination of the optimum nuclear interaction within the fast system and searching for the optimum minimum of functional connections between elements; (3) fixation of the determined narrow channel of functional connections within the fast system. The SCS switches on its mechanisms in the first stage, actively works in the second and gives up controlling in the third. To analyse the SCS functions the author employs 4 indices: (1) " h o u r oscillations" of activity, (2) "infra-slow" rhythms, (3) "wandering" bursts of activity, (4) assimilation by some nuclei of signals coming to the other nuclei. All these phenomena and their characteristics are described in detail. Changes in hour oscillations, infra-slow rhythms and wandering bursts of activity were studied in rabbits during elaboration of conditioned defense responses. The SCS provides adaptation of an organism and is supposed to relate to one of the higher controlling levels. It controls the interaction between fast independent systems and the dissonances occurring within the fast systems are its trigger. Such dissonances occur at disarrangements of reasonable brain work or at emotional disturbanees. The SCS influences every level of the control: level of interaction between parts of a neuron, between separate neurons, between brain nuclei and structures. The SCS is supposed to aid to form definite ideas concerning the rules of development of trace processes in brain control activity, which are separated by many hours from a stimulus. 4.
[Cortical single unit activity during ascending influences of varied biological significance.] Yu. A. Fadeev. Fiziol. Zh., 1965, 10: 1 1 6 9 - 1 1 7 6 .
An attempt was made to find out some peculiarities of single neuron activity in forebrain cortex under conditions of ascending activating influences of varied biological significance. Special attention was paid to the possibility of convergence on the same neuron of different ascending activating influences. In experiments in 27 hungry cats 162 neurons were studied. A single electrical stimulus was given to the contralateral sciatic nerve. The data obtained indicate that the number of discharging neurons in forebrain cortex of a hungry cat is statistically much greater than that of a cat fed before the experiment. In a hungry animal such neurons after glucose administration reduce their spontaneous firing, sometimes up to complete disappearance of discharge. On the contrary, in a fed animal the poor spontaneous firing practically does not change after glucose administration. The author supposes these facts to indicate that activation of the forebrain cortex in a hungry animal is accounted for by involvement of a g~eat many neurons in the ascending specific feeding excitation. In forebrain cortex the spontaneous firing in a hungry animal is rather inhibited by a single electrical shock to the sciatic nerve, while in a fed animal it is facilitated by the shock. The inhibition of a neuron's activity by a single electrical shock to the sciatic nerve may be regarded as a result of interaction between two different kinds of bio-
logical activation (feeding and defense) arriving at the same single neuron. Such a convergence may be called a "multibiological" convergence (Anokhin 1963). 5.
[Interaction between cerebral cortex and reticular formarion in motor dominant reactions elaborated at different levels of the central nervous system.] M. A. Riabinina. - - Fiziol. Zh., 1965, 10: 1149-1158.
The influence of a cortical focus of stationary excitation, caused by polarization, on a strychnine focus of increased excitability in the reticular formation was studied, and also the reciprocal influence from the reticular formation on the cortical focus of increased excitability. The experiments were performed in rabbits with implanted electrodes. A small direct current applied to the cortex affected in different ways the seizure activity in the reticular formation: anodal current increased it and cathodal suppressed it. An excitation focus caused by strychnine applied to the reticular formation influenced the cortex in two ways: strong focal excitation in the reticular formation immediately after strychnine application inhibited a cortical focus; on the other hand, a weak reticular focus long after strychnine application facilitated the cortical focus. In a rabbit's midbrain reticular formation a mechanism is supposed to exist, able to synchronize the EEG at 4-7 c/see and at slower rhythms (1.5-3.0 c/see). 6.
[Effects of urea on the EEG in patients with brain tumors.] V. L. Dansker, Yu. V. Dubikaitis and T. S. S t e p a n o v a . - Vop. Nel~rokhir., 1965, 6: 27-29.
In 15 patients with brain tumors and cerebral hypertension the cerebral electrical activity was studied after administration of a urea preparation. Average reference derivation was used. The EEG was recorded before and during administration of the drug at 5-10 min intervals. Heart rate, breathing and spinal fluid pressure were recorded simultaneously. E E G changes were both diffuse and local. The diffuse included general EEG improvement, decreased amplitudes, improvement of the background activity, domination of fast rhythms, bursts of synchronized polymorphous activity. Such an effect was noticed mostly in patients with posterior fossa pathology, i.e., in patients with brain-stern involvement. The local EEG changes included either lessening or, on the contrary, increase of the focal slow activity. Such different effects could be seen even in the same patient. The urea preparation is supposed to lessen cerebral hypertension, hence the E E G changes. The degree of the effect depends upon the amount of the drug and the speed of its administration. 7.
[Recruiting response in cats.] A. Roithak and N. Eristavi. - - Zh. vyssh, nerv. Deyat. Pavlova, 1965, 6: 1014-1025.
The experiments were performed on 7 cats with electrodes implanted both into the cortex and subcortical structures. Stimulating electrodes were inserted into the thalamic nonspecific system - - centro-medial or reticular nucleus. The recruiting response evoked by stimulation of the nonspecific thalamic nucleus was characterized by inconsistency of its potential amplitude, its development, its spread over the cortex, etc. "Spreading" and "concentration" of
Electroenceph. clin. Neurophysiol., 1967, 22:579-586
SOVIET PAPERS the response were observed. The recruiting response was regularly observed in the midbrain reticular formation. 6-10/see stimuli applied to the non-specific thalamic nucleus evoked a pronounced recruiting response of 2-3 see duration. The recruiting response was associated with drowsiness and suppression of motor activity, which were more pronounced with stimulation of the reticular or central medial nucleus. 8.
[Interconnection between spike discharges and evoked potentials in rabbit's visual cortex.] V. B. Poliansky. - Zh. vyssh, nerv. Deyat. Pavlova, 1965, 5: 903-910.
The correlation between slow waves and single unit discharges evoked by light stimulation in the rabbit's visual cortex was studied with monopolar leads. Quite a significant correlation was revealed between inhibition of spike discharges in the visual cortex and the large slow positive wave evoked by the light stimulation. Phases of recurring fast and slow unit potentials in the visual cortex during light stimulation are described. It is shown that alternating phases of excitation and inhibition of spike discharges in the rabbit's visual cortex during light stimulation correspond in time sequence with those in the cat's visual cortex and, according to some published reports, to the phases of subjective after-images in man. 9.
[Evoked potentials in response to electrical skin stimulation in patients with EEG focal pathology.] A. A. Sokolova. - - Zh. vyssh, nerv. Deyat. Pavlova, 1965, 5: 878-885.
Fifteen normal subjects and 25 patients with marked EEG focal pathology were studied. The most regular and marked component of the E E G response to electrical skin stimulation proved to be a potential of"non-specific response" type, in normal subjects recorded mainly from posteriorfrontal leads bilaterally and symmetrically. Occasionally the evoked potentials were asymmetrical, predominantly contralateral. In patients with focal E E G pathology the evoked potential was significantly greater in amplitude on the affected side. It was most pronounced in a region adjacent to the pathological focus. The studies of evoked potentials in response to various afferent stimuli in patients with local brain lesions show that the region of the pathological E E G focus possesses some features characteristic of a focus of dominant excitation. 10. [Participation of M-cholinergie systems in the mechanism of Aminazine (chlorpromazine) central effect.] R. Yu. Iliutehenok and R. B. Matveeva. - - Farmakol. i Toksikol., 1965, 6: 643-646. This study was carried out in 110 cats and rabbits with intact brains and with transections of the brain-stem at various levels, as well as in rabbits with electrodes implanted in the non-specific thalamic nuclei and mesencephalic reticular formation. Interaction of aminazine and drugs exciting mainly central M- and N-cholinergic structures (arecoline, nicotine) and suppressing acetylcholinesterase (galanthamine, eserine), was studied. Analysis of the data obtained showed that the Aminazine effect on the central nervous system, besides blocking adrenergic systems, also represented suppression of M-cholinergic
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systems of the reticular formation (blocking of reticulocortical activity evoked by galanthamine and eserine and blocking of the arecoline M-cholinolytic effect). However, it was noticed that the cholinolytic effect of Aminazine is much shorter and weaker than that of the central cholinolytics. The eholinolytic effect of Aminazine is supposed to be associated with blocking of both M-cholinergic neurons of the brain-stem reticular formation and M-cholinergic structures in more rostral parts of the brain. 11. [Some morphological-physiological bases of the rational reactions of the so-called non-specific brain structures. ] R. A. Durinian and A. G. Robin. - - In: "Sovremennie problemy fiziologii i patologii nervnoi sistemy" ["Contemporary problems of physiology and pathology of the nervous system"], Moscow, 1965: 256-273. The authors share the contemporary belief in the reticular formation as a heterogenic multifunctional structure. A mechanism is supposed to exist, able to carry out a primary analysis and to select the most important information arriving at the central nervous system (particularly at the reticular structures) simultaneously by different channels. Hence the authors assume that selection of the information must be carried out in every sensory system already. To solve these problems the distribution of afferent projections and types of responses in the midbrain reticular formation and the nuclei of the diffuse thalamic system were studied. A thorough electrophysiological investigation of n. centrum medianum revealed some regions connected mainly with afferent projections of the nerve studied. In the authors' opinion the data testify to the relative spatial distribution of afferent projections in n. centrum medianum. As in n. ventralis posterior, the front parts of the body project to the ventro-medial parts of the nucleus and conversely, near the rostral pole. Such a topography is considered to reflect the existence in transmitting systems of a distribution of afferent projections of various nerves. In the authors' opinion the relatively local somatotopically organized zones of representation of various afferent systems in n. centrum medianum may be regarded as sources of still more local projections to the cortex and, consequently, of less diffuse reactions, evoked by excitation of neurons of the nucleus itself. Studies of the cortico-reticular influences showed also that in the brain-stem and thalamic reticular structures the potentials with the largest amplitudes are evoked by stimulation of some definite areas of the somato-sensory cortex, i.e. foci of maximal activity of the somato-sensory areas 2 and 1. Such a dependence is accounted for by the cortico-reticular influences arising mainly from those cortical areas which first receive the information via specific transmitting systems. Experiments with local cooling of the cortical projection areas were performed in order to study the spread of cortical influences coming to the reticular structures from the projection areas of the somatosensory cortex. Alternatively, somato-sensory areas 1 and 2 were cooled and the evoked potentials were recorded in these areas and in the midbrain reticular formation or medial thalamic nuclei, during stimulation of the thalamic relay nucleus. Only the somato-sensory cortical area 2
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SOCIETY PROCEEDINGS
proved to provide close contact with the reticular structures. Some data were also obtained showing the importance of somato-sensory area 2 for the control of nonspecific thalamic activity. When studying the evoked action potentials of single neurons of the reticular structures during cooling of the cortex, data were obtained leading to the conclusion that every afferent system possesses its own cortical control of reticular activity evoked by impulses arriving by this same system. Some assumptions are made concerning the functional significance of the twofold representation of the sensory systems in the cortex. Discussing their own data and those of Andersson (1962), Carreras and Andersson (1963), Carreras and Levitt (1959), Kaada and Johannessen (1960), Segundo et aL (1955)etc., the authors presume that somato-sensory cortical area 2 does not directly participate in the delicate discriminative analysis of information but controls the activity of neurons of non-specific thalamic and brainstem structures which is associated with afferent impulses coming to these structures from the somatic and visceral systems. The authors believe that there is a sound basis nowadays for rejecting the hypothesis of the non-specific character of these structures, the absence of qualitative specific excitation in them and, consequently, to reject the very term "non-specific systems". It would be more correct to call the medial thalamic nuclei, and n. centrum medianum in particular, "secondary relay systems". 12. [Cortical electrical activity after destraction of the thalamie specific (relay) nuclei.] E . S . Moniava and R. K. Borukaev. - - Zh. vyssh, nerv. Deyat. Pavlova, 1965, 6: 1047-1054. The study is dedicated to problems concerning the significance of thalamic specific nuclei for spontaneous cortical electrical activity (EEG), E E G changes caused by lesions of different thalamic relay nuclei and the significance of these lesions for the development of recruiting responses and spontaneous spindle bursts in corresponding cortical projection areas. The experiments were carried out in cats with intact nervous systems, either immobilized with succinylcholine chloride or under Nembutal anesthesia. The results revealed that electrical lesions of the thalamic relay nuclei cause slow waves or even regular spindle bursts in corresponding cortical areas. Recruiting responses evoked by stimulation of the thalamic non-specific nuclei increase markedly after the relay thalamic nucleus has been affected, and their amplitude becomes more pronounced in the cortical area corresponding with the affected nucleus. A cortical projection area in which slow waves arise after lesion of a specific relay nucleus proves to be less affected by the desynchronizing influence of the mesencephalic reticular formation than other areas. 13. [Spread of evoked potentials over the cat's cortex during fight stimulation.] E. L. Shulga. - - Fiziul. Zh., 1965, 10: 1 1 8 2 - 1 1 8 7 . The connection between cortical projection areas and primary response spread was studied. Some cortical areas were surgically isolated from the rest of the cortex and
undercut from the lower structures. Primary responses were studied before and 2-3 days after surgery. The known latencies of visual evoked potentials all over the area from occipital to frontal pole were confirmed as being 10-15 msec. The latency regularly increased for 2-6 msec if measured from fronto-parietal to frontal areas. It hardly changed in occipital and posterior parietal areas. It is shown that circular subpial isolation of the forebrain cortex abolishes the positive phase of the evoked response or diminishes the probability of responses occurring in the isolated area. Undercutting of the cortex practically does not change the spread of the visual evoked responses in the undercut areas. In the author's opinion these results confirm his former statement concerning the genuine cortical spread of processes reflected in the visual primary cortical response. Also these results give grounds for the hypothesis of dynamic interaction between an excited focus in a projection area and processes spreading over the cortex. 14. [Heterogenic delta waves in anoxia and the postanoxie state.] A . M . Gurvitch. - - Fiziul. Zh., 1965, 10: 1 2 1 0 - 1 2 1 9 . Electrodes were inserted into the deep brain structures and placed on the dura mater of 23 dogs. Cerebral activity was studied during dying and reanimation. 59 cases of dying and 39 of reanimation were observed. Death was caused by bleeding and alternating current heart effects, reanimation was by arterial blood pumping, adrenalin administration and artificial respiration. The author discovered two types of delta waves occurring in death and during and following reanimation after complete cessation of circulation for about 0-12 min: (1) polymorphous delta waves, asynchronous in different cortical areas and subcortical nuclei; (2) standard negative-positive slow complexes, widespread throughout the cerebral hemispheres and synchronous in different areas. The polymorphous delta waves are supposed to occur as the result of cortical excitation, which is confirmed by their connection with evoked potentials of the primary response type and their being followed by local bursts of fast waves. The standard slow complexes have their own subcortical pace-maker and the cortex has nothing to do with them. Their spread all over the brain is determined both by physiological rules and the rules of potential spread in a volume conductor. The author states that, because of synchronization of the standard slow complexes in different cortical areas, they should be recorded with monopolar leads. 15. [Some means and principles of neurophysiulogical analysis of human deep cerebral structures.] N . P . Bechtereva. - - I n : "'Sovremennie problemy fiziologii i patologii nervnoi sistemy" ["Contemporary problems of physiology and pathology of the nervous system"], Moscow, 1965: 274-291. Electrophysiological study of human deep cerebral structures may be successfully carried out by means of various methods, particularly that of implanted electrodes. E E G studies under conditions of selective pharmacological influence on adrenergic and cholinergic systems provide the possibility to determine more exactly the area and Electroenceph. clin. Neurophysiol., 1967, 22:579-586
SOVIET PAPERS character of cerebral pathology and also to understand more completely some mechanisms of the so-called spontaneous (background) cerebral activity. For instance, the polymorphous pathological EEG was shown to be associated with hyperactivity of some functional systems and suppression of others, etc. Subcorticographic and EEG changes during stimulation of various deep structures via the implanted electrodes allow investigation of the interaction between deep structures arid correlation between electrical events and neurological, psychological and some other reactions.
16. [Interhemispherie relations in dogs with split brains.] V. M. Mosidze and N. B. Sheresheva. - - Zh. vyssh. nerv. Deyat. Pavlova, 1965, 6: 977-981. Animals with split brains (i.e., with all the commissures cut - corpus callosum, anterior and posterior hippocampal commissures, massa intermedia) were studied. The possibility of transferring auditory information from one hemisphere to the other and the formation of intcrhemispheric temporary connections was studied. Two chronic experiments on motor defense responses were carded out on 2 normal dogs and 2 dogs with split brains. In the normal animals the auditory information during conditioning to a sound proved to be transferred to the opposite hemisphere and fixed there. In the dogs with split brains the authors failed to observe any transference of the auditory information from one hemisphere to the other. The conditioned response formed in one hemisphere seemed to stick to it. However, a temporary interhemispheric connection could still be formed provided the excitation of both conditioned and unconditioned centers, situated in different hemispheres, was associated in time. The experiments also showed that ipsilateral auditory afferent fibers, during stimulation of only one ear, do not participate in forming the temporary connection. Midbrain structures and some other deep areas are supposed to account for the realization of the intcrhcmispheric connection.
17. [The effect of reticular impulses on single unit activity in the visual cortex.] S. P. Narikashvili, V. S. Arutiunov and E. S. Moniava. - - Zh. vyssh, nerv. Deyat. Pavlova, 1965, 6: 1 0 0 4 - 1 0 1 3 . Some peculiarities of the effect of reticular impulses on the single unit activity in the visual cortex were studied and an attempt was made to find with what characteristics of unit potentials a reticular effect is associated. All the experiments were carried out on encdphale isol~ cats. The experiments showed that reticular influences on the "spontaneous" activity of some neurons of the visual cortex are facilitating and on others inhibiting. In most cases the facilitating effect was observed in neurons that reacted to flashes. Neurons inhibited by flashes were also inhibited by reticular impulses. Under some definite conditions one or another type of reticular influence was predetermined by the frequency of firing of the neuron. The facihtatmg or inhibiting reticular effect on the neuron's response was less dependent on its type of response to light stimulation. Problems of the dependence of the character
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of a reticular effect on the type of response of a cortical neuron to light stimulation, conditions for changes in a neuron's reaction type in the visual cortex and the lack of correlation between surface response and neuronal discharge during reticular stimulation, txeitisoussed.
18. [Electrophysiological data c o n c e r n i ~ the interaction between cortex and caudate nucleust ] S . M . Butichusi. Zh. vyssh, nerv. Deyat. Pavlova, 1965, 6: 1 0 3 6 1045. Experiments were carried out on cats immobilized with alpha-tubocurarine or Lysthenon, and on enc~phale isold preparations with the spinal cord cut at the 2nd cervical segment. Identification of depth electrode placements was done according to Jasper and Ajmone-Marsan's Atlas. When a single stimulus was applied to the caudate nucleus in intact cats a spindle burst of slow waves was observed in the cortex and some deep structures: both caudate nuclei, mesial, medial and ventral anterior thalamic nuclei, hypothalamus and the midbrain reticular formation. These spindle bursts increased after transection of the medial part of the brain-stem near the anterior corpora quadrigemina. This reaction gradually decreased with further transections near the mesial-medial and central lateral nuclei and altogether disappeared after transection of the medial part of the thalamus near the ventralanterior nucleus. On fast stimulation of the caudate nucleus (50-200/see) suppression of thalamo-cortical responses in the sensory cortex and facilitation of responses in the visual cortex occurred. After an electrical lesion of the midbrain reticular formation the fast stimulation of the caudate nucleus no longer facilitated responses in the visual cortex but still suppressed the responses of the sensori-motor cortex. After short tetanization of the sensori-motor cortex (2-3 sec) neuronal discharges in the caudate nucleus evoked by stimulation of the contralateral forepaw were facilitated. During an after-discharge evoked by tetanization of the sensorimotor cortex (5-7 sec) every burst of clonic waves in the cortex caused cellular discharges in the caudate nucleus.
19. [Slow shifts of cortical potential during stimulation of medial thalamic nuclei.] Z. P. Shuranova. - - Zh. vyssh, nerv. Deyat. Pavlova, 1965, 4: 705-710. Experiments were carried out on 15 rabbits immobilized by Diplazine or tubocurarine. Electrical activity was recorded with calomel electrodes connected with a cotton wick (for electrocorticography) or a capillary through a salt solution. The results revealed dissimilarity of cortical responses to stimulatmn of medial thalamus. First, an essential difference between responses to low and high frequency stimulation of the thalamlc structures was discovered. At the low frequency a local surface negative shift of the cortical potential was observed, which either could not be found in deeper layers or had an inverse polarity there. At the high frequency either a diffuse shift of cortical potential was observed or it was more pronounced in the deep cortical layers and absent or positive
Electroenceph. clin. Neurophysiol., 1967, 22:579-586
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on the surface. This surface negative shift of the cortical potential is supposed to reflect a stable depolarization of elements of the surface cortical layers. It was also shown that high frequency stimulation of the medial thalamus was accompanied by two variants of slow shifts of the cortical potential differing from one another in duration, vertical distribution of the negative component, connection with different cortical rhythms and different sensitivity to Nembutal. From the results obtained the author singles out the first type of reaction ("thalamic") and the second ("reticular"). It is assumed that the character of the cortical response to stimulation of the medial thalamus depends essentially upon the functional state of the animal. Against a relatively inhibited background, when stimulation is not followed by excitation of the brainstem reticular formation, a response of the first type occurs, whereas against a more activated background that of the second type occurs. 20. [Spontaneous discharges of the neurons of the somatosensory cortex and peculiarities of their functional organization.] N. N. Vassilevsky. - - Fiziol. Zh., 1965, 6: 710-716.
In this study the author tries to find out how the peculiarities of organization of cortical neurons affect the level and character of their background activity. Two series of experiments were carried out on cats and rabbits immobilized by Procuran or Lysthenon. A surface monopolar electrocorticogram was made, with recording of unit potentials. Receptive fields were determined for every neuron under study. Spontaneous firing of different functional types of neurons of the somato-sensory cortex has three main forms: single discharges, bursts and groups of discharges. All three forms are described in detail and an assumption is made that these variants of spontaneous firing are predetermined by time and amplitude peculiarities of depolarizing processes in the neuron soma. Further, it is noticed that, in cats, fast activity in the somatosensory area corresponds with frequent spontaneous firing. It is also shown that in cat's and rabbit's somato-sensory cortex different functional types of neurons have different levels of spontaneous firing. The highest spontaneous firing rate was observed in non-specific neurons (28.2+ 2.2 and 13.3 :L 2.0/sec in cats and rabbits respectively) and the least rate in non-activating them (8.9 ± 2.3 and 6 . 6 ± 1.2/sec). Middle values were characteristic of specific neurons. In the author's opinion the difference in spontaneous firing of neurons in the somato-sensory cortex of cats and rabbits is reflected in their subcortical rhythms. 21. [Cholinesterase and brain waves during eserine and galanthamine effects in animals with pre-mesencephalic transections.] R. Yu. Iliutchenokand L. N. Nesterenko. - - Byull. eksp. Biol. Med., 1965, 10: 57-60.
Experiments were carried out on 37 cats. Cholinesterase activity was determined by Ponosian's photoelectro-colorimetric method. The E E G was recorded with steel needlet inserted into the skull. The brain-stem was transected jus
~aefore anterior corpora quadrigemina above and after corpora quadrigemina below (pre-mesencephalic transection) and between anterior and posterior corpora quadrigemina (Bremer's cerveau isold). In pre-mesertcephalic transection cholinesterase activity in the brain after galanthamine is suppressed everywhere as in intact animals. E E G activation could not be revealed in spite of the nearly complete cholinesterase suppression in pretransection areas (in diencephalic area up to 10.7-16.9 % of normal, in the cortex, 0.03 %). Comparison of the cholinesterase effects in cerveau isold and intact animals revealed that even two or three times smaller doses of galanthamine and eserine suppressed the effect and activated the EEG. Consequently the cholinesterase E E G activation depends upon suppression in the mesencephalic areas. 22. [Neurochemical mechanisms of ascending cortical activation in hungry animals.] K . V . Sudakov and A. I. Turenko. - - Byull. eksp. Biol. Med., 1965, 10: 3-7. Cholinergic mechanisms maintaining cortical activation in hungry animals were studied. Experiments were carried out on 40 cats under urethane anesthesia after 24 h of food deprivation. Scalp EEGs and etectrocorticograms were recorded. In hunger a selective EEG activation in the forebrain cortex appeared, while in posterior areas high voltage slow waves characteristic of sleep were seen. Cholinolytics (atropine, Amizil) usually caused high voltage slow waves in the forebrain areas of hungry animals. Application of the drugs to the cortex abolished the activation in the forebrain cortex and had no effect on pain EEG activation. It is concluded that cholinolytics block the mechanisms of feeding adaptation. In order to study neurochemical mechanisms of cortical synapses, we investigated evoked potentials caused by sciatic stimulation during hunger activation of the forebrain cortex and after abolishing the activation with cholinolytics. The experiments showed quite distinct chemical peculiarities in the cortical axo-dendritic synapses during the different biological reactions. Some chemical peculiarities during different biological reactions are supposed to be intrinsic to subcortical structures, 23. [Nivalin and Amizil effects on the EEG and alerting response in man.] T . P . lsakova. - - Zh. vyssh, nerv. Deyat. Pavlova, 1965, 6: 1113-1121.
Himwich and Rinaldi (1955, 1957), Longo and Silvestrini (1957), Iltchenok and Mashkovsky (1961) and others showed that acetylcholine and its derivatives, as well as some anticholinesterase drugs of the physostigmine type (eserine, galanthamine, Nivalin) caused the same EEG activation as any afferent stimulation, while cholinolytic drugs (atropine, Amizil and others) are known to exert the contrary effects. Anitchkov and Denisenko (1962) singled out these drugs as a special group of central cholinolytics because of their ability to block mainly interneuronal cholinergic structures in the central nervous system while having relatively weak peripheral seffects. Art attempt was made to find out how Nivalin (inElectroenceph. clin. Neurophysiol., 1967, 22:579-586
SOVIET PAPERS creasing sensitivity of brain cells to acetylcholine) and Amizil (suppressing the cerebral cholinergic structures) affect different components of the alerting response in healthy men and patients with paranoid schizophrenia. Nivalin was tested in 15 healthy men and 21 patients, Amizil in 20 healthy men and 22 patients. Nivalin increased the amplitude of the alpha rhythm and made it more regular and improved bioelectric, autonomic and motor components of the alerting response both in healthy and diseased men. After Amizil gradual decrease of the alpha amplitude and replacement of the rhythm by low voltage slow waves were observed both in healthy and diseased men. Under Amizil stimuli evoked increase of the alpha rhythm all over the cortex. The cholinergic structures are supposed to participate in the genesis of the h u m a n alpha rhythm. 24. [Significance of serotonin for central nervous system activity.] E. A. Gromova. - - In: "So~Temennie problemy fiziologii i patologii nervnoi sistemy" ["Contemporary problems of physiology and pathology of the nervous system"[, Moscow, 1965: 346-357.
Some biologically active drugs are essential for complicated processes of neuro-humoral control of the organism's functions. Serotonin is quite important amongst these drugs. High concentrations of serotonin in some cerebral structures, high effectiveness of the drug on cerebral functions etc. make the assumption of serotonin as a mediator quite reasonable. However, there are many contradictory reports concerning the role of serotonin in the central nervous system. Effects of serotonin on spontaneous cerebral electrical activity and evoked potentials, on the excitability of some cerebral structures and segmental reflex processes in the spinal cord, were studied in rabbits with implanted electrodes. In discussing the data obtained the author indicates the serotonin effect on the functional state of different parts of the central nervous system. A biphasic serotonin effect with a prevailing second prolonged activating phase is shown. A primary serotonin effect on the subcortical activating structures is supposed. A n observed serotonin effect on the hypothalamus allowed the assumption that serotonin-induced changes in it participate in the mechanisms of circulatory control. 25. [Electrophysiological data concerning the role of the cerebral cortex in the genesis of oxygen seizure.] I. B. Voronov. - - Fiziol. Zh., 1965, 7: 777-783.
In 41 experiments on cats changes of cerebral cortical spontaneous activity caused by high oxygen pressure were studied in intact brain and cerveau isold preparations. In cats with intact brains one of the first signs of the high oxygen pressure effect is E E G desynchronization. During oxygen seizures high voltage "hypersynchronized" discharges are observed in the EEG. After separation of the forebrain areas from the lower parts (cerveau isold) the oxygen seizure does not appear in cats. Also the E E G changes characteristic of high oxygen pressure are absent. In the cerveau isold even after long-lasting high oxygen pressure the ordinary sensitivity of the forebrain to the effects of corazol, eserine, arecoline, atropine and dipha-
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sine are preserved (eserine and arecoline are drugs with cholinomimetic effects; atropine and diphasine are cholinolytics usually restoring sleep spindles). The forebrain is not the most sensitive part of the brain to the toxic effect of oxygen. Presumably the midbrain reticular formation is the starting link in the oxygen intoxication. 26. [Electrophysiological study of some human deep structures with implanted electrodes. ] T . G . Urmantcheeva and N. I. Diakonova. - - Fiziol. Zh., 1965, 8: 909-917.
Electrical activity of ventro-lateral thalamic nuclei and globus pallidus was studied in 5 patients operated on because of various hyperkinesias. From 6 to 12 electrodes were implanted in each patient. The subcortical electrical activity was characterized mainly by waves at 4-6 c/sec but 2-3, 8-12 and 18-24 c/sec waves were also observed. The amplitudes of the waves varied from 25 to 70/~V. Contralateral motor responses were observed during stimulation of globus pallidus and the ventro-lateral thalamic nucleus: blinking, winking, making fists, head turning, contraction of mimic, shoulder and spinal muscles. Some changes in the electrical activity of the subcortical structures were also observed: in the stimulated and adjacent areas amplitude changes and sometimes slow waves appeared. After stimulation of th~ ventro-lateral thalamic nucleus, with increasing tremor in the contralateral hand, amplitudes decreased in the subcortical structures. Stimulation of the globus pallidus, giving no apparent changes in the patient's motor behavior, was accompanied by high voltage slow waves in this structure and flattening of electrical activity in the ventro-lateral thalamic nucleus. These stimulation-induced electrical changes were quite short. Severe electrical changes were observed in subcortical structures after stimuli followed by complicated sensations and autonomic responses. In one patient after stimulation of the deepest area of the ventro-lateral thalamic nucleus, which evoked sensations of flicker in the eyes, coldness in the stomach and nausea, a pronounced electrical activity (9-10, 12-14 c/sec waves of 200-300 #V amplitude) was observed in the deep structures. During such a subcortical activity amplitudes of the occipital E E G increased and regular 14 c/sec waves appeared in the frontal EEG. The authors presume that motor responses and subjective sensations evoked by stimulation of the globus pallidus and ventro-lateral thalamic nucleus are accompanied by corresponding changes in electrical activity of these structures and in the E E G patterns. 27. [Role of dendrites in mechanisms of signal detection.] N. A. Aladjalova. - - Zh. vyssh, nerv. Deyat. Pavlova, 1965, 6: 1088-1097.
A n attempt was made to find a principle underlying comparison of signals converging on a neuron with formerly established criteria. The author studies the principle of functional organization of synapses in a system and gives a particular example of its realization; further, experimental data concerning some properties of dendrites supporting the discussed principle in a real neuron are considered. Electroenceph. clin. Neurophysiol., 1967, 22:579-586
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The author concludes that the model principle of signal detection consists in transforming the distribution of the model elements from haphazard to regular. The regular condition is formed by the information flow itself, which establishes correlations between distribution of impulses in a signal and distribution of elements by conditions; in case of correlation the summed response of the model overcomes the noise level. The distribution is based on comparison of impulse sequence and intervals in synapses. The model principle may be realized in a dendritic device of signal detection containing axons and a dendrite with its synaptic apparatus in a bifurcation area. The principle requires, on the one hand, a one-step inflow of impulses and signal intervals to the dendritic synapses and, on the other, a coincidence of pre-synaptic and postsynaptic excitation in those synapses, the condition of which must change. It is possible because of the contrary spread of impulses along the dendrite from the bifurcation. Experiments on the axe-dendritic cortical strip of a rabbit's brain show two spike potentials in response to the first stimulus (pre-synaptic and post-synaptic) while, with repeated stimuli (up to 6 times), a post-synaptic slow negative wave is gradually formed reflecting, presumably, the gradual formation of a dendritic response parallel to the growth of correlation between synapse distribution by conditions. During short-term retention of traces local shifts on the neuroglial interface play a certain role. The princible shares the standpoint that specific information storage is determined by internal connections in the neuronal groups. The model of signal detection in dendrites makes it possible to transfer from studying single synapses to studying the whole organization of synapses in functional systems. 28. [A physiological mechanism for the spread of nervous processes over the cerebral cortex.] A . B . Kogan. Zh. vyssh, nerv. Deyat. Pavlova, 1965, 6: 963-969. Basic items of the physiology of higher nervous activity (spread of excitation and inhibition) are discussed in detail. The nature of the spread was thoroughly investigated with indices of background electrical activity, evoked potentials, changes in excitability and conditioned responses. In experiments with undercut cortex desynchronization evoked by flashes, sounds and other stimuli was seen, spreading over the undercut cortex with no ascending activating influences. Desynchronization in the undercut cortex differed from that in intact cortex. In the author's opinion this difference was accounted for by the activating influence of ascending reticular pathways; the ability for active transmission of the nervous processes inherent in the cortex may be increased and altered by ascending influences. In another series of experiments a possible mutual influence of one cortical area over the excitability of another, without direct participation of cortex-subcortical pathways, was discovered (Kogan and Zaguskin 1961). However, abolishing the direct cortico-subcortical interaction sharply changed the influence of one cortical area over others. Unequivocal proofs of a n authentic cortical spread of a conditioned excitation were obtained in experiments with undercutting or circumcutting of cortical
areas. Electrical stimulation of these areas was used as a signal for food conditioned responses (Kogan 1961; Glumov 1962). These experiments showed the transcortical pathways to be more important for realization of the response than cortico-subcortieal connections. In the author's opinion the spreading phenomenon is of a cortical nature and the ascending influences of the reticular system are necessary to maintain a high level of excitability and working ability of the corresponding cortical mechanisms. Tkatchenko and Shulga (1964) studied the spread of visual evoked potentials from occipital to frontal lobes in cats. The mean velocity of spread over the undercut cortical area ranged from 2.0 to 5.0 m/see, which is quite similar to the velocity of 1.5 m/see found by Micld and Edds for the spread of auditory electrical responses. Undercutting did not lessen the velocity of the visual response spread. From the viewpoint of single unit activity successive involvement of the cortical neurons in the response to electrical stimulation of the skin was revealed by differences in the latencies of their action potentials. The time characteristics of this involvement were similar to those of spread of excitation waves (Livanov 1963). Simultaneous recording of action potentials of several neurons showed that they are involved by groups (Kogan and Gorayan 1965), which is why the spread of excitation might have the discrete character of stepped motion of the nervous process. Thus in the author's opinion both the fast processes of neuronal discharges and the slow processes of interaction between functional neuronal groups participate in the spread of nervous processes, as welt as the controlling influences ascending from subcortical structures. These three kinds of process revealed in the investigation of cortical spread represent three levels of its realization, not three possible mechanisms. 29. [Rayaaud's disease. Clinical and pathophysiologieal study of the central nervous mechanisms.] N. P. Bechtereva, A. V. Bondarchuk and V. V. Zontov. - Published by "Medicina", Leningrad, 1965. In the E E G of patients with Raynaud's disease significant polymorphism is a prominent feature: in some cases there is marked prevalence of desynchronization, which may be steady or alternate with bursts of spreading synchronous activity, in other eases there is high synchronization of alpha rhythm or bursts of monomorphous and polymorphous activity of high voltage; sometimes synchronous beta rhythm of low frequency is observed. Trigger and rhythmic photo-stimulation tend to evoke a paradoxical response. The effects of Aminazine, amphetamine and Nivalin on the E E G of patients with Raynaud': syndrome were analysed and disclosed imbalance be tween adrenergic-cholinergic systems. The observed poly morphism of changes in the E E G testifies that in these cases inhibition of one functional system may be accom partied by activation of the other. It is supposed that th. development of Raynaud's disease is mostly determined by dysfunction of non-specific structures of the brainstem and more rostrally located diencephalic formations.
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