Stages in the development of neuroses in the dog and effects of preparations with antidepressive and tranquilizing properties

In modelling of neuroses, successive stages of development of this pathology were observed in dogs. The first stage is characterized by circular disturbances of conditioned activity, vegetative shifts of compensatory character and intensification of individual characteristics of behaviour. At the second stage, parallel with sharp disturbances of conditioned reflexes and with vegetative dystonia, a distortion of emotional reactions was observed in dogs. It is essential that resumption of neurotization episodes in experiments on dogs with the second stage of disease promoted a development of depressive-like states. Diazepam corrected the behavioural and vegetative shifts at the first stage of neurosis. Non-typical antidepressants eliminated the manifestation of symptoms complex of the disease, especially at prolonged treatment.     

Conditioned reflexes following unilateral damage to the premotor cortex and the dorsal portion of the head of the caudate nucleus in dogs

The study was carried out on dogs by the secretory-motor method with a two-side reinforcement. Simultaneous and unilateral lesion of the premotor cortex and of the dorsal part of the caudate nucleus head brought about prolonged disturbances of the vegetative components (pulse and respiratory rate) and in the choice of the side of food reinforcement. The change in the magnitude of conditioned salivation, latencies of secretion and motor reaction was temporary, and by the end of the third postoperative period their initial magnitudes were restored. The duration of the disturbances of higher nervous activity depended on the localization and extent of lesion of the caudate nucleus head. Tests were made with chlorpromazine and caffeine before and after the lesion of the brain structures. The tests in the postoperative period revealed latent disturbances in the dog higher nervous activity. It is assumed that the premotor cortex and the dorsal part of the caudate nucleus head are one of the sub-systems involved in the regulation of vegetative, somatic components of unconditioned behaviour and in the analysis of conditioned stimuli.     

Motor alimentary conditioned reflexes and delayed reactions in dogs following destruction of the caudate nucleus]

The characteristics of formation and achievement of motor conditioned reactions were studied in seventeen dogs before and after the lesion of head or body of the caudate nucleus. It has been shown that the degree of higher nervous activity disturbances depends on the localization of injuries in the nucleus, and on the complexity of the tests used. The caudate nucleus exerts a modulating effect on the parameters of motor conditioned reflexes and takes a direct part in the structure of delayed reflexes. Lesion of the caudate nucleus body is attended with more serious disturbances of higher nervous activity than lesion of its head.     

Integration of conditioned reflex systems in intact and callosotomized dogs

Characteristics of integrative activity were studied by Kupalov's method of situational conditioned reflexes in 2 groups of dogs with complete section of the callosal body and in group of intact animals. The dogs of the first group were callosotomized before the formation of the conditioned reflex systems, the dogs of the second group--after their stabilization. The level of the reflex systems integration in the first group was considerably lower than in the second one. This testifies to a special role of the callosal body in the initial period of formation of complex conditioned systems. The callosotomized dogs developed inertia of nervous processes which was manifested in slowing down of formation and of adaptive realization of reactions during integration of various reflex systems. It was shown that the integrative activity is provided for by the interaction of cerebral hemispheres at different structural levels.     

The role of the orbital cortex in feeding behavior]

It has been found that extirpation of the orbital zones of the cerebral cortex in dogs in which the structures of the limbic and striate levels of nervous integration were previously ablated, produced more profound disturbances of the higher nervous activity than the previous operations. Not only conditioned positive and inhibitory reactions were affected, but unconditioned alimentary reflexes as well, while food motivation sharply decreased. Further experiments on the operated animals and could go on, only when alimentary excitability was enhanced. A conclusion has been drawn that the orbital zones of the cerebral cortex are directly related to the achievement of an integrated alimentary behavioral reaction.     

Characteristics of the formation of conditioned defense reactions in monkeys in a primatological chair

Rate of reactions in motor conditioned electro-defensive reflexes and different kinds of internal inhibition, such as acute extinction, differentiation and delay with different retardations, were studied on monkeys in primatological chair. Specificity in formation of conditioned reactions was studied with simultaneous recording of vegetative (respiration and heart rate) and motor conditioned reactions. It has been established, that forming of vegetative and motor components of defensive reflex does not proceed synchronously. At first (2-4 trials) vegetative reactions appear, such as increase of heart and respiration rates. Conditioned motor reactions (legs' jerks) appear later, after 4-9 trials. It has been shown that in monkeys in the primatological chair we have a possibility to form all kinds of negative conditioned defensive reactions: acute extinction, differentiation, delay. Formation of delay inhibition with retardation of 90 s leads to neurotic disorders. But they last only for short periods and disappear after breaks in work. The obtained data are discussed from evolutionary point of view, with a comparative study of specificity of higher nervous activity formation among lower organized vertebrates and with consideration of processes of excitation and inhibition in evolution.     

Comparative aspects of a study of the self-regulation of higher nervous activity in experimental neuroses in dogs, cats and rats

The higher nervous activity has been studied by means of motor-alimentary conditioned reflexes and delayed reactions in dogs, cats and albino rats at early stages of development of experimental informational neurosis. It was shown that formation of stable pathological reactions is preceeded by self- regulational activity of the brain directed towards elimination of a pathological situation, as well as to the increase of the stability of the nervous system to pathogenic agents. Comparative studies on rodents and predatory animals indicate that in different species the same pathogenic effects on the brain may elicit different forms of self-regulation of the higher nervous activity.     

Typological characteristics of dogs in the initial period of the development of neurosis

In the initial period of neurosis, significant differences were found in changes of motor and vegetative reactions in dogs of dissimilar typology. Animals with strong type of the nervous system displayed cyclic transitions from the normal state to the initial stage of pathology and vice versa. Such transitions were practically absent in dogs of the weak type. A method is proposed providing efficient classification of experimental dogs according to their types of higher nervous activity and differentiation of the normal state and the initial stage of neurosis.     

Relation between the level of conditioned reflex activity and concentration of serotonin in the blood of normal and neurotic dogs

Higher nervous activity of dogs was studied using Pavlovian method of alimentary salivary conditioned reflexes. Serotonin (5- hydroxytryptamine) content in the venous blood was defined by means of fluorescent spectrofluorimeter using orthophthalic dialdehyde. A high level of conditioned and unconditioned reflexes was accompanied by a low serotonin blood content, while a low level of reflexes was accompanied by a high serotonin content. Negative correlation is supposed to exist between the degree of activation of nervous processes and blood serotonin content. Blood serotonin content increased in dogs in experimental neurosis with expressed reduction of the level on alimentary conditioned and unconditioned reflexes.     

Comparative pathology of higher nervous activity

In experiments with defensive behaviour, using multiparametric recording of indices, studies have been made on the origin and development of pathological disturbances in the higher nervous activity of insectivores, carnivores and primates during presentation of difficult conditioned reflex problems or extreme stimulation. It was found that elaboration of absolute differentiation retarded conditioned reactions with a delay of 25 s in insectivores is a difficult task which results in pathological changes in the higher nervous activity. In hedgehogs, neurotic changes are immediate, all the investigated indices being affected. In carnivores, especially in primates, the onset of evident pathological changes is preceded by a long preneurotic period, i.e. a stage of self-regulation. In pathological process, more corticalized forms of the nervous activity are initially involved. Common features and differences in the development of pathological changes in the higher nervous activity among mammals are discussed.     

The dynamics of the rats higher nervous activity disturbances after total influence of electrons and gamma-rays in doses 5-100 Gy

The dynamics of using of stabilized motor defensive conditioned reflex of active avoidance in "shuttle-box" in rats after total influence of high energy electrons and of gamma-rays in doses 5-100 Gy were investigated. The quality structure of higher nervous activity disturbances after the influence of these kinds of ionizing radiation was identical. Therefore the tendency to disturbances aggravating after the electron radiation influence in the periods of the initial depression and of relatively normalization was revealed, especially after the irradiation in dose 50 Gy. The effective compensation of the functional disturbances in the central nervous system at the first 5-10 min after irradiation was after influence of electron radiation in doses about 30 Gy and after the influence of gamma-radiation in doses about 50 Gy. The irradiation of rats in doses 10 Gy and 5 Gy caused qualitative different dynamics of radiation disturbances in rats higher nervous activity. The differences in rats higher nervous activity after influence of electron and of gamma-radiation in these doses did not manifest distinctly.     

Peculiarities of modifying influence of the factors forming the functional status of the central nervous system on dynamics of the rat higher nervous activity disturbances totally exposed to electron and gamma-radiation at a dose of 100 Gy

The dynamics of using a stabilized motor defensive conditioned reflex of active avoidance in "shuttle-box" in rats after the total influence of high energy electrons and gamma-rays at a dose of 100 Gy and a modifying influence of the two most important factors forming the functional status of the central nervous system: the stage of the conditioned reflex consolidation and typological peculiarities of the higher nervous activity have been investigated. The influence of both types of ionizing radiation has been shown to cause far more profound disturbances of non consolidated conditioned reflexes in comparison with the automatized conditioned reflexes and provoke an inverted picture of disturbances in the animals with opposed peculiarities of the higher nervous activity. The qualitative picture of the dynamics of disturbances that are caused by these types of radiation is identical. In summary, the studied conditions that form the functional status of the central nervous system determine the nature of neuroradiation syndrome to a greater extent than differences in the effectiveness of these types of radiation.     

Conditioned reactions and mediator-humoral shifts during neurotization in a probabilistic pain reinforcement situation

Substitution of regular partial reinforcement for random one (in both cases the reinforcement frequency was 50%) acted in some dogs as a neurotizing factor: they showed unrest, stable defensive reflexes disappeared, corresponding changes were observed in vegetative reactions. At the same time activation of the sympatho-adrenal system was recorded along with a drop in concentration of acetylcholine in peripheric blood. It is noted that the development of neurotic disturbances in dogs in these conditions were to a certain degree dependent of the dominating motivation.     

The dynamics of the brain heat fields of rats in the late postresuscitation period during stress]

By thermoencephaloscopy method the temperature relief of the rats cerebral cortex was studied after the clinical death and reanimation. The rehabilitation of the animals neurological status was completed in 1-2 days. In the remote postresuscitation period (up to 2 months), expressed disturbances were revealed of the background thermomaps and of thermal reactions of the cerebral hemispheres, evoked by the stress influence. Pathologic mosaics of thermal characteristics was revealed in conditions of relative rest and disturbance of dynamics of the brain temperature reactions and the character of interhemispheric asymmetries at stress influence. Individual character is pointed out of postreanimative pathology, which is manifest both in the background thermomaps and after the functional load. The results of the studies suggest the importance of individual approach in rehabilitation therapy of postreanimative disease.     

Spontaneous recovery of precise movement and of the postural fixation of the extremities after excision of the somatosensory cortex in dogs

The extirpation of the foreleg area in the somatosensory cortex (SI) in dogs was performed in order to study the role of this area in motor control of the corresponding limb. Stable precise avoidance and escape reactions were established before the cortical lesion. Avoidance reactions disappeared during the first week after the surgery but then they were gradually restored without retraining. At the third weak there was a practically complete recovery of the precision of movements, the ability to fix the leg position and of the duration of successive phases of the reactions. The conclusion was drawn that the initial disturbances of avoidance reactions were most likely the result of diaschisis (shock). The initial disturbances of visually guided instrumental movements and escape reactions were much weaker than those of avoidance reactions (lifting of the foreleg in response to conditioned signal).     

Disruption of situational reflexes in experimental neurosis brought on by changes in the space factor

Motor activity elaborated in dogs and consisting of delayed choice reactions in a stochastic system (methods developed by Beritashvili, Hunter) and of rhythmic stereotypes of motor situational reflexes (Kupalov method) was not impaired by changes in spatial parameters of unconditioned stimulus in the stochastic system of choosing one feeding trough out of five. The changes in the spatial arrangement of conditioned and unconditioned stimuli in stable stereotypes led to changes in the behaviour of the animals and experimental neurosis with long-lasting disturbances in the situational conditioned reflexes and the short-term memory.     

Experimental informational neuroses in dogs as sequelae of overloading short-term memory

In conditions of overloaded function of short-term memory, studied by the method of delayed reactions, with a prolonged deficit of time allotted for realization of the function, the animals exhibit substantial disturbances of higher nervous activity which by their etiological character belong to the group of informational neuroses. Appearance of the neurosis is preceded by a number of complex behavioral and vegetative changes reflecting activation of powerful compensatory mechanisms of the brain activity, aimed at elimating the time deficit and other neurotizing factors of the surroundings. Experimental neurosis caused by overloading the function of short-term memory is characterized by a severe course and is attended with motor and somatic disturbances as well as by memory and emotional disorders.     

The effect of vasopressin on memory processes in Macaca fascicularis]

The role of vasopressin (arginin-vasopressin) in the regulation of conditioned instrumental food-procuring reactions and different kinds of memory such as delayed reflexes, image, short-, and long-time memory was studied in monkeys. Motor and autonomic effects of vasopressin were assessed. It was found that in monkeys, vasopressin administration differently affected the simple conditioned food-procuring reactions and memory. During functional disorders of the higher nervous activity, vasopressin was more efficient in its action on memory and its restoration. Formation of two types of vasopressin effects on the higher nervous activity in evolution of mammals is discussed.     

Changes in the correlations of the different indices of the entire behavior of dogs under the influence of seduxen

During chronic use of seduxen various changes of correlation connections between different parameters of general behaviour are revealed in dogs. The character and degree of expressiveness of these changes depend on the drug dose and typological characteristics of animals. The most general and significant manifestation of favourable effect of the drug action on animals behaviour is an increase of the number of "strong" correlation connections (correlation coefficient is more than 0.7) of the parameters of various components of conditioned activity, reflecting the state of inner inhibition processes, and to the parameters of vegetative provision of conditioned reactions. The character of reconstructions of correlation connections between different conditioned, vegetative, neurotransmitter and general behaviour parameters allows to judge of the direction of pharmacological influence on separate functional systems and the behaviour as a whole.     

The effects of intracerebral injections of kynurenine on conditioned reflex activity and on the serotonin level of the blood in dogs]

Higher nervous activity of dogs was studied by classical Pavlovian method of alimentary salivary conditioned reflexes and serotonin content in blood was measured. Kynurenine sulfate in a dose of 300 + 300 mkg (bilaterally) was injected in the dorsal hippocampus region through chemiotrodes. In most cases the injection of the substance led to changes towards excitation (increase of conditioned and unconditioned alimentary salivation in the day of injection and the next day) and also to a rise of serotonin content in animals blood.