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The responses of osphradium in the fresh-water mollusk Viviparus sp. and single osphradial neurons in the pond snail Lymnaea stagnalis to L-glutamine and L-asparagine as well as the changes in these responses under the effect of heavy metals (Cu, Cd) were recorded electrophysiologically. The functional connections of osphradium with the identified neurons of the central pattern generator of respiratory movements and cardiac activity as well as the modification of these connections under the effect of short-term application of HgCl2 solution on the snail's osphradium were investigated. The cardiac rhythm in the mollusk Littorina littorea under the effect of Cu ions was registered non-invasively in long-lasting experiments. The dose-dependent short-term effects of heavy metals changes after osphradium injury were revealed. The implication of osphradium in adaptive reactions of the cardiac system in aquatic mollusks to the environmental heavy metal pollution is suggested. The dependence of cardiac rhythm on the degree of accumulation of copper ions in the mollusk tissues was detected. The results obtained are essential for unraveling neural mechanisms and pathways allowing heavy metals to affect the functional state of hydrobionts, particularly, the cardiac activity frequency characteristics of which are widely used as informative biomarkers to assess physiological condition of aquatic invertebrates.

By the method of non-invasive on-line recording and processing of photoplethysmograms of testaceous invertebrates, the circadian rhythm of cardiac activity was studied in the crayfish Pontastacus leptodactylus by recording for several months the heart rate (HR) and stress-index (characteristics of variational pulsometry). The crayfish were kept in the natural running water in the regime of natural illumination alteration (the first group) or at constant artificial illumination of low intensity (the second group). The circadian rhythm was more frequent and more distinct in crayfish of the first group. The criteria were established to determine the appearance and stabilization of the nocturnal, active rhythm phase: an increase of HR by more than 30% as compared with daytime rest period and duration of such increase for at least 2.5 h. The stress-index has been shown to be a reliable parameter of the beginning of the nocturnal phase of cardioactivity, while preservation of the typical circadian rhythm can be considered as a bioindicator in the biomonitoring systems of the quality of superficial waters.

The characteristics of learning in ants - active Myrmica rubra foragers - were studied in a maze at different levels of colony carbohydrate food need with reinforcement consisting of carbohydrate (sugar syrup) or protein (pupae of Lasius niger ants). Measures of the maze skill during learning reinforced with syrup were somewhat worse than those during learning reinforced with pupae, especially in terms of time-based measures. Ants were able to modify the acquired conditioned reflex reaction when the quality of reinforcement changed. At high levels of food need (" hungry" colony), substitution of syrup with larvae and vice versa was followed by transformation of the previously formed skill; this occurred at both experimental periods (training and testing). At low levels of motivation ("sated colony"), the optimized maze habit formed with protein reinforcement was replaced in the test with carbohydrate reinforcement by a "stochastic," unoptimized behavior with a dominance of investigative activity. These experiments demonstrated that conditioned reflex switching can occur in higher social insects - ants - in which the different forms depend on the level of colony need for food and, respectively, on the level of social food-related motivation of forager ants. The special importance of using the switch activating the corresponding motivational system before changing the reinforcement food quality is emphasized.

Active foragers Myrmica rubra were trained in a maze under conditions of different levels of colony need in food with carbohydrate (sugar syrup) or protein (ants Lasius niger pupae) reinforcement. Acquisition of the maze habit was better under conditions of reinforcement with pupae, especially by its time indices. Ants were able to modify the acquired habit when the reinforcement quality was changed. It was shown that learning was possible only when the colony and after a change pupae for the syrup was "hungry". Under these conditions, after a change of the syrup for pupae or visa versa the previously acquired optimum habit was transferred. Several hours later, with satiation of the colony, food reactions learned with protein reinforcement switched-over to "stochastic" non-optimized behavior with the dominance of exploratory reactions. Thus, it was shown that higher social insects ants were capable for conditioned switching-over. Different forms of this phenomenon depended on the level of the colony need in food and, consequently, on the level of the social food motivation of foragers ants.

The ability of Myrmica rubra scout ants to modify the foraging habit, formed in a symmetrical multiple-choice maze, in the situation in which the reinforcement (syrup) was replaced with a brood of the same species was studied. When the "test" was performed at the same high level of food motivation of the family as applied during training, the ants were able successfully to transfer to another type of social behavior - transporting of the brood. When the high-level food motivation was replaced with a low-level motivation, some of the ants were unable to modify the habit. Preliminary utilization in these conditions of reinforcement as a switching factor addressing the motivational system for protective behavior promoted successful performance of the "test." Criteria allowing identification of different methods of modifying behavior during the switch from food motivation to protective motivation were developed. A total of 37.5% of the ants transferred the strategy formed during training: 40.6% showed gradual remodeling. while 21.9% of individuals immediately used the new strategy.

It was shown that scout ants Myrmica rubra are capable for an adequate modification of foraging habit acquired in a multichoice symmetrical maze following a reward change (syrup for the species brood). Under conditions of the high level of food motivation of a family both during learning and "examination" (i.e., brood transportation) all the ants succeed in a conditioned switchover of heterogeneous reflexes. If the high level of motivation during learnings is changed for its low level during examination, some ant do not realize the new task. The unconditioned switch (preliminary 1-3 brood takes at the start ares) facilitates the successful performance. In different experimental sessions a certain ratio was revealed between the ants realizing different ways of correct decision making. Specially developed criteria made it possible to identify different individual types of behavior during examination: transfer of acquired strategy, its gradual adaptation, and fast switchover to the new strategy. The adequate maze method and learning on the basis of specific forms of social behavior of ants (foraging, brood transportation, and exploratory activity) promote the rapid and efficient acquisition of the habit and its modification.

Learning in ants was studied in a multiple choice symmetrical maze at different levels of social food motivation. Myrmica rubra scout ants were found to be able to change their behavioral strategy rapidly when families were suddenly changed from a low level of motivation to a high level and vice versa. In the "sated" state, there was clearly evident investigative activity, which led to high levels of variability and instability in the maze habit. In the "starved" state, there was a rapid minimization of movement trajectories, and most ants used only one dominant movement scheme. The initial level of food motivation determined how ants learned in the maze and their ability to change their behavioral strategy.

Learning of ants was studied in a symmetrical multi-choice maze at different levels of food "social" motivation. A capability was shown of scout ants Myrmica rubra for changing rapidly behavioral strategy when the motivation level of a family changed from the low one for the high or vice versa. In the satiated state the ants demonstrated a clear-cut research activity. This activity was associated with high variability and instability of the maze habit. In the "hungry" state movement trajectories were rapidly minimized, the majority of ants used one dominant scheme of moving. Initial level of motivation determined the peculiarities of and learning and ability to transform behavioral strategies.

Motor, Searching and alimentary activity of male mice BALB/c as well as spatiomotor asymmetry was studied under conditions of training in symmetrical multi-alternative maze. In the period of realization of the stable optimal habit the right-side spatially motor asymmetry was observed in intact males. In animals with inactivated left or right hemisphere motor and alimentary activity was reduced and the structure of elaborated maze habit was broken. These changes were more expressed in mice with inactivated left hemisphere. Searching activity was augmented during cortical inactivation of the right hemisphere (this was associated with the right-side spatially motor asymmetry) and reduced during inactivation of the left hemisphere (associated with the left-side asymmetry). The left hemisphere was dominant in realization of all main components of elaborated maze habit (including the spatially motor asymmetry) in male mice BALB/c as in female ones.

Ability was shown of ants Myrmica rubra to multiple reconstructions of the habit elaborated in symmetrical multialternative maze under motivation of care for the progeny (transportation of breed of the own species). Reconstruction consisted in the change of reinforcement location on the left or right aim spot. The ants showed the ability to carry out the series of eight reconstructions during one-two days. An improvement took place of the fulfillment of the last reconstructions in comparison with the first ones. Peculiarities of learning and reconstructions were found in two groups of animals differing by conditions of learning: at reinforcement on both ain spors or on one of them. The results obtained are considered as indices of high plasticity of the behaviour of ants of the studied species.

At tachistoscopic unilateral presentation of noisy visual stimuli and application of "yes-no" method in man predominance was found of the right hemisphere by the number and "yes" reaction time and of the left hemisphere by the number of responses "no". At verbal mnemic load preceding the presentation of visual patterns the left hemisphere asymmetry was observed by the number of "yes" responses and reactions time of both types. FMA was more clearly expressed in men in the first case and in women--in the second one. In more difficult conditions of recognition of several types of patterns, FMA was noticed mainly in women: initial left hemisphere advantage during the increase of the disturbance was changed to the right hemispheric one and appeared again. Preferential participation of the right hemisphere in singling out of the visual signal from noise is supposed. Possibility of the left hemispheric asymmetry manifestation was determined by the specificity and complexity of the visual task, by the level of the disturbance, presentation of competitive task and sexual composition of the group.

Behaviour of Gammarus oceanicus was studied in the open field test. For the whole except (n = 204) spatial-motor asymmetry was found. It was manifested in significantly greater number of movements clockwise (to the right) than counterclockwise (to the left). Animals with significant asymmetry dominated, forming 93.5% of the except. The asymmetry was characterized by distinct right-sided direction. Motor activity and spatial-motor asymmetry at repeated tests in the main weakened; the changes in "right" and "left" animals were manifested differently. The essential factor which disturbed the behaviour of the animals in the open field test (including the asymmetry of movement direction) proved to be a toxicant (oil pollution) action.

The problem of behavioral plasticity in insects was studied with red ants, Myrmica rubra, by altering a habit developed in a multi-alternative labyrinth with care for offspring as motivation. In altering the habit, location of reinforcement was changed: in the first series, the brood was transferred from the target areas to relatively symmetrical areas of the transverse axis of the labyrinth; in the second, reinforcement was left on one area that had not been preferred during learning of the target area. In both situations, the ants displayed the ability to alter labyrinth habits. The first alteration was the more complex, and 62.5% of the ants were able to manage it while 87.5% managed the second. Such indices as the first correct solution, the average number of movements in the cycle, and total number of correct cycles were also poorer for the first alteration. Development of a new motor habit was accompanied by a change (intensification) of the initial spatial-motor asymmetry. Individual variability in ant behavior were more evident in alterations. The animals not able to manage alterations exhibited definite preneurotic traits. It is suggested that ants have high plasticity and ability to successfully modify their behavior to correspond to change in the experimental situation.

In conditions of tachistoscopic presentation of visual stimuli, healthy (male and female) right-handed subjects carried out a paired comparison of the stimuli presented unilaterally and in the center of the visual field. In case of recognition of images of words and objects, the number of correct answers and motor reaction time usually did not significantly differ at two interstimuli intervals (1 and 10 s). In comparing images of faces, there also were no differences by the number of reactions, and the reaction time was less at the intervals of 1 s. The left hemisphere dominated at the identification of words and female faces, the right one--at the recognition of male faces. When the right visual field was stimulated images of various classes were recognized more differentially than at the stimulation of the left visual field. The male subjects had more prominent interhemispheric differences than the females. The increase of the interstimuli interval from 1 to 10 s brought to a weakening of the functional interhemispheric asymmetry and decreasing of the differences between the male and female subjects. The obtained data show that in the processes connected with short-time memory, functional interhemispheric asymmetry is basically formed at the initial stages of the information processing.

The comparison of histograms of distribution of monocular and binocular EPs amplitudes in the striate and parastriate cortex of intact and callosectomized cats with the corresponding histograms of intensities of random light flashes revealed a transformation of stimuli distribution function. In intact animals, EPs distribution was characterized by a left-side asymmetry and predominance of mean-amplitude EPs. It is suggested that the above distribution characteristics reflect the principle of optimization. Its presence as well as characteristics of its manifestation in definite visual areas and with different types of stimuli lateralization are largely due to transcallosal influences modulating the value and power spectrum of thalamocortical excitation.

The ability of Wistar rats to recognize the texture-statistics of the I-st order with near threshold 10% difference between the stimuli was shown. Unilateral cortical inactivation usually impaired texture differentiation and decreased the noise resistibility of the visual recognition. The effect of the right hemisphere inactivation was more pronounced than that of the left one. Sex differences in texture recognition were revealed. The images with greater differences of statistic characteristics were better recognized by intact females and those with the lesser ones were better recognized by males. Certain level of texture recognition by the intact animals of either sex was formed with participation of facilitatory influences of both hemispheres, especially of the right one. The influences of the same type were shown in males in respect to the noise resistibility of the visual recognition, while in females the influences of the right hemisphere were facilitatory and those of the left one were inhibitory.

Motor alimentary conditioned reflex was elaborated in Wistar line rats to presentation of various pairs of figures, those of larger area serving as positive signals. In tests on animals with intact brain and with unilateral hemispheric cortical inactivation, new pairs of figures were used besides basic stimuli. The level of analysis in testing experiment was lower than normal: by 5.6% at intact brain, by 16.4%--at right hemisphere inactivation, by 36.4%--at left hemisphere inactivation. Elimination of the left hemisphere produced prolongation of the conditioned reaction time, signs of frustration and aftereffect. In conditions of right hemisphere inactivation the level of discrimination of figures depended on their specific properties and the side of presentation. Conclusion is made on dominating role of the left hemisphere in analysis of abstract and concrete characteristics of visual stimuli, in control of temporal, spatial and emotional characteristics of reactions in situations when considerable abstraction and distinguishing of generalizing invariant sign "more-less" is necessary for elaboration of the conditioned reflex.

Transcallosal responses to stimulation of the cortex at the depth of 0.5 mm had the least phase I and the greatest phase II as compared with their values at a deeper stimulation. The maximal phase II occurred at the 1 mm stimulation. At a fixed depth of stimulation the maximal amplitude of the phase I coincided with the depth of stimulation. At 1 and 2 mm stimulations, the second maximum of the responses occurred at the depth of 2 and 1 mm, resp. The data obtained suggest that the callosal connections are organized in a "layer--to--layer" way, and that there are some cross--connections between the layers III and V ("one layer--another layer").

The influence of photic interference is manifested in animals (in cats) with an intact callosal body mainly in EP depression. The extent of EP depression depends directly on the strength of the interference and is inversely related to that of the determined stimulus. In some cases yet another effect, facilitation of EP may be manifested during the action of a weak interference. These facts are considered to result from postrevely. Section of the callosal body is followed by a weakening of the depressing influence of photic interference on EPs elicited by a certain stimulus, as well as by an enhancement of the facilitating influence on EPs of weak photic interferences. A stronger influence of a binocular photic interference, as compared with a monocular one, has been established in intact and callosotomized animals. A conclusion has been drawn that the interference resistance of a split brain is stronger than that of an intact one. A comparison of the interference resistance in the primary and secondary cortical visual projection zones has shown that after callosotomy interference resistance in the striate cortex increases to a greater extent than in the parastriate area.

Transformation of stimuli contrast in animal visual system was revealed in experiments on cats and rats anaesthetized with Nembutal. With zero contrast, there was an initial functional interhemispheric asymmetry (FIAs) of evoked potentials (EPs) in the fields 17 and 18. Dependence of the initial FIAs on stimulation intensity was defined. The sign of the initial EPs asymmetry was stable in cats (right hemisphere) and unstable in rats. Differences in interdependence between FIAs and contrast were found in both animals. In cats, in a wide range of stimuli contrasts, the sign and value of the interhemispheric asymmetry were stable and close to the initial FIAs; while in rats FIAs value directly depended on stimuli contrast and its sign corresponded to that of the contrast. The role of transcallosal influences in the formation of certain EPs FIAs properties was traced down. The discovered characteristics of contrasts transformation seem to contribute to a more reliable functioning of the visual system.

The characteristics of binocular interaction in the visual cortex were studied in rats and cats in conditions of dichotic presentation of monocular stimuli changing in intensity in opposite directions. Different combinations of stimuli intensities produced in intact animals a predominance of facilitation of binocular EPs. Depression of EPs was seen in rats subjected to weak contralateral and strong ipsilateral stimuli. After callosotomy EP facilitation in cats was less pronounced. In rats both effects of binocular interaction were enhanced and were recorded in conditions of photostimulation opposite to preoperational ones. It was found that the differences in the effects of binocular interaction before and after callosotomy resulted from changes in occlusional interrelations and elimination of transcallosal influences. An assumption is made that the effects of binocular interaction are largely responsible for specific characteristics of the formation of interhemispheric asymmetry in binocular vision.

The preference of movement direction in the process of motor food conditioned reaction has been investigated in rats with intact brain and after unilateral cortical inactivation. It was shown that the degree of motorspatial preference diminished with the maturation of reaction. At the high level of differentiation the valid preference was shown only in 38% of animals investigated but it was absent in the rest of animals. After inactivation of right hemisphere cortex left-side preference occurred in the presence as well as in the absence of the original preference. Inactivation of the left hemisphere cortex is less significant; it influences the original preference of movement direction permanently affecting those animals which normally had evident preference. It is concluded that the right hemisphere cortex plays dominant part in both sensor and motorspatial components of motor food conditioned reaction. It is supposed that the definite relationship exists between the degree of preference of movement direction and the functional asymmetry of cerebral hemispheres.

The behaviour of mice of BALB/c line was studied in a symmetrical multialternative Y-maze: their motor, alimentary and investigating activities as well as spatial-motor asymmetry. In animals with inactivated left hemisphere, as compared to intact ones, the motor and alimentary activities were lowered, and the investigating one augmented. Instead of the weak left-side asymmetry a distinct left-side preference appeared of most Y-maze sections, and right-side preference for approaches to the feeders. Elimination of the right hemisphere did not change the motor activity; the alimentary one decreased and the investigating one augmented, but less than during inactivation of the left hemisphere. On the whole, the right-side asymmetry appeared for all sections. According to all parameters studied, the influence of the left hemisphere on animal behaviour was more expressive and diverse. Spatial preference is formed with participation of influences of both hemispheres. The differences between them are more qualitative than quantitative.

Recognition of structured visual stimuli under the action of light interference was studied by means of conditioning in rats with intact and dissected callosal body. Addition of noise to conditioned signals was achieved by insertion of additional element into their image. It was found that as more noise was added the number of correct responses decreased and latencies of conditioned food-procuring reactions became longer. The number of individuals in the sample, which possessed a differentiation level higher than the random one decreased. Noise immunity of males in the range of weak and average noises proved to be higher than in females, and, as a rule, equal at high noises. Section of the callosal body produced changes in noise immunity of visual recognition; the nature and degree of the changes depended on the intensity of noise and on the animal's sex. The existence of modulating callosal influences on noise immunity of visual recognition is suggested.

Bilateral mechanisms, the hemisphere specifics and the sexual dimorphism of the visual system's resistance against hindrance were studied in conditioning and electrophysiological experiments in rats and cats. A right-sided specialization of the hemisphere control over visual recognition in noise and its resistance against hindrance was revealed in rats: activity of the right hemisphere aids to a greater extent to picking up of relevant signal out of noise than that of the left hemisphere. Role of bilateral mechanisms in the visual system's resistance against hindrance was described in cats and rats: after the callosotomy the picking up of relevant signals out of noise could either improve or get worse, depending on a number of conditions. The dominant mechanisms were shown to play a major part in formation of a certain level of the resistance. Both the intact and the split brain seems to be more resistant against hindrance and to have a greater asymmetry in males. The data obtained contribute to corroboration of presence of the brain lateral specialization in animals and are interpreted on the basis of the inductive-deductive hypothesis of the brain lateralization origin.

It has been shown that in animals with an intact corpus callosum the influence of photic interference is mainfested above all in EP depression. The degree of EP depression is directly dependent on the strength of the interference and is in inverse relationship with the strength of the determined stimulus. Against the background of a weak interference an other effect is possible in some cases, i.e. facilitation of the EP. These facts are interpreted as a result of postresponse subnormality of neurones and as excitation summation respectively. Section of the corpus callosum results in a weakening of the depressing effect of the photic interference on the EP appearing in response to a determined stimulus, and in an enhanced facilitating influence of weak photic interferences. A stronger influence of binocular photic interference as compared with the monocular one was observed in intact and callosotomized animals. A conclusion has been reached that the split brain has a stronger interference resistance as compared with the intact one.

Asymmetry in direction of motion was found in Myrmica rubra ants at their learning in a symmetrical multi-alternative maze in conditions of "social" alimentary motivation. It was manifested in the form of preferable stay in the right half of the maze and was significant by several parameters: total number of motions, approaches to "false" spots and right turns. Unequal degrees of spatial-motor asymmetry (individual and for the whole sample) was revealed by various parameters. Most clearly the right-sided spatial preference was seen in the insects which had more approaches to goal with reinforcement taking than "exploratory" approaches. It is suggested that the parameters of motion direction asymmetry in ants learning in the maze depend on the level of alimentary "social" motivation.

The ability was studied of Myrmica rubra ants to change the habit of passing through a multialternative symmetric labyrinth at motivation of the care for posterity. In exams the location of reinforcement was changed: in the first exam the progeny was carried from both aim places to those symmetric to them relatively to labyrinth cross axis; in the second exam the reinforcement was left on one aim place non-preferred during learning. The first exam was passed by 62.5% of ants, the second--by 87.5%. In the first exam such parameters were worse as the first correct decision, the mean number of movements in the cycle, the total number of correct cycles. At elaboration of new motor habits and increase and inversion were observed of the initial spatial-motor asymmetry. Individual variations in ants behaviour increased. The ants who failed to solve the task, showed pronounced signs of preneurotic state. The obtained results testify to a high plasticity of ants behaviour and their ability to modify their activity according to changes of experimental situation.

Anodic polarization of the parastriate area in the right hemisphere causes in symmetric regions of cat's visual cortex dynamic changes in EPs, interhemispheric functional asymmetry and interhemispheric relations, depending on the intensity of photic stimulation. The sequence of phases of interhemispheric callosal relations and characteristics of interaction between callosal and extracallosal influences were traced in different periods of polarization excitation. It was found that interhemispheric callosal and extracallosal influences lead either to stabilization of initial EP levels and interhemispheric asymmetry or to their change depending on conditions of photostimulation and on the stage in the formation of polarization site.

This study shows the existence of right-sided lateral specialization of hemisphere noise resistance control of visual discrimination in rats. As a rule, right hemisphere activity, to a greater degree than left hemisphere activity is conducive to the improvement of noise resistance, the left hemisphere sometimes making it worse. Indications have been obtained concerning the existence of sex dimorphism of noise immunity in rats' visual discrimination. It is possible that the intact and split brain are more noise resistant in males than in females and are characterized by a greater asymmetry. The role of bilateral mechanisms in noise resistance is described: after section of the corpus callosum, noise resistance may either improve or deteriorate. It has been found that interhemispheric asymmetry can be changed up to its inversion by means of one of the hemisphere's polarization.

Asymmetry of movement direction was found in Wistar rats at establishing of motor alimentary conditioned reflex to simultaneously presented visual stimuli. In the course of learning the asymmetry weakened on the whole, but some individuals retained right- or left side preference. The analysis of asymmetry change before and after unilateral cortical inactivation revealed a special role of right hemisphere influences for the formation of right-side preference and of the left hemisphere--for the choice of the left direction. The lack of asymmetry was observed at the presence of the influences from the left hemisphere cortex depressing ipsilateral nigro-striate system and activating the contralateral one. Influences of the cortex of both hemispheres reduce the absolute value of the asymmetry coefficient; the left hemisphere has a special significance for manifestation of temporal asymmetry parameters. Photic interference is a factor modulating the asymmetry. It reduces the right hemisphere activity more than that of the left one; it intensifies right hemisphere influences, contributes to the involvement of the transcallosal conduction channel in the formation of spatial-motor asymmetry.