[The ethical aspects of physiological experiment].

A modern classification of invasive procedures developed according to International Bioethical Principles has been presented. The experimental data convincingly demonstrate that using of noninvasive approaches and techniques give a good opportunity to reduce a number of animals recruited in experiment as well as to keep the normal (not distressful) physiological functions of animals. The data presented stress that development of noninvasive techniques is closely related both to scientific and social aspects of our life, allowing the scientists to provide high validity of experimental data obtained as well as to keep themselves as a human beings.

Involvement of the nucleus accumbens in the formation of spatial selection reactions in rats in a radial maze.

Studies on rats demonstrated that lesioning of the medial shell of the nucleus accumbens led to impairment of the ability of experimental rats to perform error-free identification of the arm containing the largest amount of reinforcement in a radial maze. The behavioral deficit was not associated with impaired motivation or sensorimotor learning ability, as there was no such deficit in operated rats during sequential presentation of local discriminant stimuli identifying the location of the forthcoming reinforcement. These data suggest that the medial shell of the nucleus accumbens, which receives convergent projections from the ventral hippocampus, amygdala, and ventral tegmental area, plays an important role in organizing the spatial orientation of the animal in the direction of the preferred reinforcement in conditions of a sensory information deficit.

Analysis of the action of the neuropeptide-inducing delta-sleep in cats and white rats.

Suboccipital administration of the oligopeptide to adult cats and white rats in a dose of 15 and 20 micrograms/kg induces the appearance of electrographic (delta-sleep) and behavioral sleep within 15-25 min. Administration of the oligopeptide induces a substantial increase in the thresholds of the response of the EEG to phonostimulation. A substantial lag (50-90 min) in the onset of paradoxical sleep is noted, which is considered by the authors as a manifestation of inhibition, exerted by the neuropeptide on the further development of the sleep mechanisms. On the basis of the data obtained it is concluded that natural sleep and that induced by the neuropeptide are nonequivalent.

[Effect of emotional stress on sleep dynamics in cats]. / Vliianie émotsional'nogo stressa na dinamiku sna u koshek.

Emotional stress was developed in cats by putting them in one cage with dogs for 24 hours. Then the 24 hours sleep-walking cycles records revealed prolonged REM stage in day time or at night in five animals out of seven, and in six animals a general increase of REM sleep duration over 24 hours. Simultaneously, in six animals the length of drowsiness and of deep slow-wave sleep stages was reduced. Increased overall sleep duration in the 24 hours was recorded in five cats. Sleep changes dynamics analysis reveals three stages: 1) sharp shift of all sleep parameters--27%, 2) deviation in sleep parameters--34% and 3) returning to basic sleep parameters--in 38%. The conclusion is drawn that sleep disorders may be used as an index of higher nervous activity disturbance in waking state.

[Participation of the neostriatum in mechanisms of instrumental behavior]. / Uchastie neostriatuma v mekhanizmakh instrumental'nogo povedeniia.

The paper is devoted to the study of the neostriatum role in the mechanism of instrumental learning. In the experiments on cats with damaged dorsal segment of the caudate nucleus head, deficit of forming new instrumental reflexes and achieving complex tasks was revealed. Damage of the caudate neucleus had a most pronounced negative influence on the process of differentiation elaboration. High- and low-frequency stimulation of this structure in dogs did not disturb solution of an instrumental task: the end result was achieved, but the characteristics of many parameters of the motor act--latency, amplitude, duration--were significantly changed. The presented facts suggest that the basal ganglia play functionally different roles in the period of formation of instrumental conditioned reflexes and in the period of realization of consolidated connections. Possible mechanisms of neostriatum participation in the processes of elaboration and realization of instrumental reflexes of various motivational value are discussed.

[Participation of the dopamine-reactive system of the caudate nucleus in regulating instrumental conditioned reflexes of various degrees of complexity]. / Uchastie dofaminoreaktivnoi sistemy khvostatogo iadra v reguliatsii instrumental'nykh uslovnykh refleksov raznoi stepeni slozhnosti.

Administration of dopamine into the dorsal part of the caudate nucleus' head hindered the instrumental feeding conditioning with tonic form of motor response in cats. In preliminarily conditioned animals, dopamine impaired the tonic phase of the conditioned response and, consequently, made them loose the ability to synchronize the food-seeking motor response with the moment of food reinforcement. Special series of experiments were performed to study the character of motor disturbances revealed in the tonic phase of the instrumental conditioning as well as their relation to the level of initial motivation. Role of the caudate nucleus dopamine-reactive system in the mechanism of delayed inhibition, is discussed.

[Electrical activity of layers of isolated cortex during drowsiness and different sleep stages]. / Eelktricheskaia aktivnost' sloev izolirovannoi kory pri zasypanii i raznykh stadiiakh sna

In cats with isolated cerebral cortex, with the aid of electordes indwelled into different cortical layers, first electrographic changes during onset of sleep were shown to occur, as with intact cortex, in the lower layers of the isolated cortex. 3-4 months after the cortex isolation, changes of electrical activity during sleep occured simultaneously in the cortex of both hemispheres. Awakening produced desynchronization of electrical activity in all cortical layers of both hemispheres. Origin of primary electrical activity changes in the lower cortical layers, is discussed.

[Local temperature characteristics of the isolated cortex in wakefulness and alteration of the sleep stages]. / Kharakteristika lokal'noi temperatury izolirovannoi kory pri bodrctvovanii i smene stadii sna.

In cats, changes of the brain electric activity were followed by local temperature shifts in isolated and in intact cortex: the transition from slow wave sleep to paradoxical sleep and from quiet to active wakefulness were accompanied by increasing of the cortex temperature, while transition from paradoxical sleep to slow sleep decreased the temperature. During falling asleep and alternation of the sleep stages, both in isolated and intact cortex, the temperature shifts preceded the electric activity changes. The temperature of isolated cortex is by 0.2 degrees lower than that of the opposite intact hemisphere.

[Electrographic changes in isolated cat cortex under the influence of sleep neuropeptide]. / Elektrograficheskie izmeneniia v izolirovannoi kore koshek pod vliianiem neiropeptida sna.

Experiments on adult cats with isolated cerebral cortex show that suboccipital olygopeptide administration (10 and 15 mg/kg) induces electrographic manifestation of the slow wave sleep (SWS) in the isolated cortex. Slow synchronous waves reflecting the onset of SWS appear in the isolated cortex 0.2-1.5 sec earlier than in the control hemisphere. The same administration prevents the onset of paradoxical sleep (PS) up to 2 hours from the beginning of the experiment. In all experiments, manifestation of the PS was recorded in both hemispheres simultaneously.

[Participation of the nucleus accumbens in acquisition of spatial choice behavior in rats performing in a radial plus maze]. / Uchastie prilezhashchego iadra (n. accumbens) v formirovanii reaktsii prostranstvennogo vybora u krys v radial'nom labirinte.

The role of medial shell of the nucleus accumbens in acquisition of spatial behavior was studied in rats performing choice task in radial maze with asymmetrical water reinforcement. It has been found that the nucleus accumbens lesioned rats failed in finding larger rewards but preserve their reward-seeking behavior guided by visual discriminative stimuli. The results obtained are in good agreement with suggestion that the nucleus accumbens is a site of convergence of spatial information (from hippocampus) with reward information (from amygdala and VTA), providing bridge for effective limbic-motor interface underlying motivated goal-directed behavior in animals.