[Individual prognostic behavioral features in dogs during the choice between probability and value of reinforcement].

A strategy and latency of choice between the probability (100, 50, 30, 20 and 0% probabilities were tested) and value (high and low) of the reinforcement were investigated in dogs. The greatest differences in dogs' behavior were observed under conditions of uncertainty when the valuable reinforcement was presented with probabilities from 50 to 20%. According to subjective evaluation of uncertain situation, dogs were divided into "inclined to risk" (more frequently choosing low-probable but valuable food) and "careful" (more frequently choosing high-probable but less valuable food).

[Features of differential inhibition in choice between alimentary and defensive response].

Instrumental defensive (avoidance/escape) and alimentary responses (reinforced with palatable food) in dogs were conditioned by the same stimulus (6-Hz light flashes). Differential inhibition for these responses (0.6-Hz flashes) was formed in unalterable series.

[Functional regional asymmetry of the EEG intrahemispheric coherence in dogs during conditioning].

Individual features of the regional interhemispheric relations in the brain were studied in dogs during alimentary conditioning. The electrical activity was recorded from symmetrical anterior (frontal and motor cortices) and posterior (visual and auditory cortices) areas of the neocortex. Comparison between the averaged left and right intrahemispheric EEG coherences revealed a dynamic character of interhemispheric relations dependent on the stage of conditioning.

[Individual typological features of the dog behavior during the choice between food and avoidance of electrocutaneous stimulation].

Two conditioned reflexes (CR) on flash were elaborated in five dogs in three experimental series. In one of them pressing on pedal were constantly reinforced with two pieces of liver, in other--escape or avoidance of skin stimulation with lifting of leg. In a third series, series of reinforcement choice, in front of animal with electrodes, fasting on leg, put the pedal.

[Effects of prefrontal ablations on the reaction of the active choice of feeder under different probability and value of the reinforcement on dog].

The role of the prefrontal cortex was investigated on the reaction of the active choice of the two feeders under changes value and probability reinforcement. The experiments were performed on 2 dogs with prefrontal ablation (g. proreus).

[EEG dynamics during conditioning in symmetrical neocortical regions in dogs].

Changes in the frequency of the EEG recorded in symmetrical areas of the frontal and auditory cortices were studied during food conditioning in four dogs. Spectral-correlation analysis was applied. EEG frequency changes depended on individual features of the animals, frequency band, and stage of conditioning.

[Functional asymmetry of the neocortex electrical activity during food conditioning in dogs].

Four dogs were trained to perform a conditioned alimentary response to a sound stimulus. The EEG was recorded from six pairs of chronically implanted neocortical electrodes. The EEG spectra and coherence functions between the neighboring derivations of each of the hemispheres were analyzed in the theta, alpha, beta 1 and beta 2 frequency ranges.

[The asymmetry of cerebral hemispheric activity in dogs in a state of quiet wakefulness under the action of sensory stimuli and food deprivation].

The EEG was recorded in four dogs from symmetrical cortical areas of the left and right brain hemispheres. Activation foci were determined by the maximal values of the mean frequency of EEG oscillations and coherence function. In the background experiments, the hemispheric activation asymmetry was observed in all dogs.

[The novelty factor and asymmetry in brain activity].

In case of repeated presentation of monotonous tasks or stimuli, based upon EP and EEG parameters, the zone of increased activation in human cortex in which the shortest EP latent period, the highest alpha-rhythm frequency were recorded did not remain stable but as the stimulation continued, shifted from the frontal region of the left hemisphere to the occipital region of the right hemisphere. It was shown in dogs that introduction of combination of the conditioned stimulus with food reinforcement resulted in an increase in the number of cases with maximal values of EEG frequency in the left hemisphere. In cats during orienting reaction to clicks, correlation between averaged EPs of the auditory cortex, amygdala and hypothalamus was dominant in the left hemisphere.

[The intercentral relations of the frontal cortex and limbic structures of the brain in dogs].

In 3 dogs with implanted electrodes, in conditioned experiments correlation of the bioelectrical processes was studied by coherence function calculation of the hippocampus, hypothalamus, amygdala and frontal cortex biopotentials. It was shown, that the level of maximum values of coherence function of bioelectrical oscillations, led from various pairs of the studied brain structures significantly differed both in magnitude and frequency at which the greatest synchronization of biopotentials was noticed. In one dog with a high degree of connection between the hippocampus and hypothalamus biopotentials oscillations, a low synchronization of the frontal cortex and amygdala oscillations was found; in two other animals with a higher level of coherence between the oscillations of the frontal cortex and amygdala biopotentials, a lower degree of connection between the oscillations led from the hippocampus and hypothalamus was revealed.

[The dependence of hippocampal electrical activity on the probability of the reinforcement of a conditioned food stimulus].

In three dogs the dynamics was studied of changes in the number of instrumental motor reactions, the heart rate and the hippocampus theta rhythm was studied at the change of constant reinforcement to various regimes of probable reinforcement of alimentary conditioned stimulus. At 70 and 50% levels of the reinforcement the instrumental reflex appeared in response to all presentations of the signal stimulus. The greatest decrease in the number of reactions took place at 5% probability.

[A comparative neuropsychological approach to the analysis of hippocampal functions].

Formation of conditioned switching-over of heterogeneous instrumental reflexes in dogs was more successful than in rats, which testifies about significant differences of the functional organization of analytical-synthetic brain activity in rodents and predatory animals. Experiments with lesion of the hippocampus (in rats) and the records of its electrical activity (in dogs) allowed to conclude that the hippocampus of the both types of animals belongs to the system of structures, participating in the formation of conditioned switching-over. The data, obtained in the process of elaboration of the switching-over and probabilistic reinforcement of the alimentary conditioned stimulus, testify that providing for the reactions to signals with low probability of reinforcement in different species of animals is one of the functions of the hippocampus.

[Conditioned reflex and electrical activities of the hippocampus during the random use of heterogeneous triggering stimuli].

In dogs with electrodes chronically implanted in the hippocampus, the conditioned activity, heart rate frequency and spectral characteristics of the hippocampal theta-rhythm were studied in conditions of irregular presentation after a preparatory stimulus now of alimentary and now of defensive triggering conditioned stimuli. It is shown that uncertainty of alimentary or defensive reinforcement is a stronger emotiogenic factor than the action of the triggering defensive conditioned stimulus. Changes in electrical hippocampal activity and autonomous activity depend, along with other factors, on forecasted volume of the forthcoming motor activity.

[Changes in the electrical activity of the hippocampus during elaboration of an inhibitory reaction in the dog].

A conditioned alimentary instrumental reflex was elaborated in three dogs with chronically implanted electrodes to a consecutive complex conditioned stimulus consisting of two equal acoustic stimuli separated by a pause. At first, the animals reacted with motor reactions during the whole action of the complex signal. Then inhibition of reaction was elaborated at first in pause and then in response to the preparatory stimulus.

[Dynamics of the spectral composition of the hippocampal theta-rhythm in the dog during switching-over of heterogeneous instrumental reflexes].

In two dogs with electrodes chronically implanted in the hippocampus, hippocampal electrical activity and the heart rate were recorded in the process of elaboration of a conditioned switch-over of operant alimentary and defensive responses. Averaged computerized spectral characteristics of hippocampal theta-rhythm were essentially different between the alimentary and defensive situations in intersignal period as well as during the action of triggering conditioned stimulus. Individual differences in the dominant frequency of bioelectrical activity were observed.

[Correlation of electric potentials of the hippocampus, amygdala and neocortex during instrumental conditioned reflexes in the dog].

Coherence and spectral functions of biopotentials of the hippocampus, amygdala, frontal and sensorimotor cortical areas were estimated in dogs during instrumental alimentary behaviour and during self-stimulation of emotionally positive brain areas. Formation of functional systems: frontal cortex--amygdala, frontal cortex--hippocampus, and sensorimotor cortex--amygdala, synchronously acting in delta- and theta bands of electrical activity, was observed at the stage of a stabilized motor habit. THe hippocampus and amaygdala poorly co-operated, probably reflecting their different roles in the organization of behaviour.

[Changes in the frequency of the hippocampal theta-rhythm in the dog exposed to a conditioned food stimulus].

Frequency changes of hippocampal theta-rhythm in the process of elaboration of coinciding or delayed instrumental alimentary reflex was studied in two dogs. Determination of dominating frequency of rhythmical activity was carried out by means of mathematical methods of analysis on a computer. It was found out, that during the action of conditioned alimentary stimulus the frequency of dominating oscillations became enhanced.

[Instrumental heterogeneous responses to 2 successive complex stimuli with a common initial stimulus in the dog].

Formation and achievement of heterogenous instrumental reflexes to two consecutive complex stimuli was studied in dogs. Under the action of conditioned complex stimulus tone--Pause--tone, the dogs may be trained not to have a motor response to the first tone presentation, but perform alimentary instrumental reaction only to its repeated administration. Introducing into the experiment not only alimentary but also defensive complex stimulus stone-pause--light resulted in a change in animal's reactions in such a sequence: at first alimentary instrumental reaction was disinhibited under the action of the preparatory stimulus and during the pause, then bieffector responses appeared, further on in most of the dogs motor defensive reactions mainly took place.

[Individual features of hippocampal electrical activity and conditioned reflex behavior in dogs].

The experiment was made on 14 dogs, with electrodes chronically implanted in the dorsal and posterior parts of the hippocampus. In all the dogs the frequency of dominating rhythmic activity depended on the level of the animals [emotional stress. It was shown that the frequency of dominant rhythmic activity of the dog hippocampus is an individual characteristic.

[Emotional stress during conditioned reflex transformation of heterogeneous instrumental reflexes].

The factors leading to pronounced emotional stress accompanied by changes in electrical activity of hippocampus were studied in four dogs during elaboration of conditioned switching-over of heterogeneous instrumental reflexes. Objectively recorded signs of emotional stress were observed in two cases: when the animal was not accurate enough in discerning defensive and alimentary situations and throughout the improvement of instrumental defensive reflex. Pronouncement of hippocampal theta-rhythm increased at those stages of switching-over elaboration where the probability of successful avoiding pain stimulation was relatively low.

[Dynamics of elaboration of conditioned reflex switching over of dissimilar instrumental conditioned reflexes].

Conditioned switching over of heterogeneous instrumental reactions was elaborated in four dogs. The action of a fan served as a switch from alimentary to a defensive situation. In the alimentary situation, the animal, in response to a conditioned stimulus, pressed the pedal with its right foreleg and, in a defensive situation, in response to the same signal, lifted the left paw attached to the lever.