Natural 1st and 2d degree conditioned food reflexes in the dog in relation to space orientation

In three dogs formation and performance of spatial alimentary natural conditioned responses of the second order was studied when the dog had to find food preliminarily shown to it in one of the four food-distributors (psychonervous activity directed by a food image in terms proposed by I. S. Beritashvili). Characteristics of this form of behaviour were demonstrated and discussed: rapid formation, dependence of performance on the delay time, conflict between responses of the first and the second order. In the second series of the experiments food-procuring behaviour of dogs was studied under conditions of conflict between the quality (value) of alimentary reinforcement and probability of its finding in certain food-distributor. Such kind of behavior was shown to depend on the motivation level and individual characteristics of the dog. Interaction of "informational" (anterior areas of the neocortex, hippocampus) and "motivational" (nuclei of amigdalar complex, hypothalamus) cerebral structures is supposed to underlie the organization of behaviour.     

The relation of the typological classification of dogs to their behavioral characteristics in variations between the probability and the value of reinforcement]

In studying of dogs behaviour in coordinates system "Requirements and probability of their satisfaction" it has been established that selection of behaviour strategy is closely connected with individual typological properties of animals. In experiments with equally-probable alimentary reinforcement a direct correlation was found between the strength parameter of the nervous system and the strategy of dogs behaviour. Animals of strong types manifested the character of reaction which consisted in determination and goal-directedness, while the animals of the weak type manifested other character, having features of uncertainty, indefinition, hesitations. In conditions of conflict between probability and value of reinforcement the dogs manifested two opposite strategies of behaviour: orientation to highly probable events (choleric and phlegmatic) and to low-probable events (sanguinic and melancholic) what is connected with individual properties of functioning and the character of interaction of four brain structures (frontal cortex, hippocampus, hypothalamus, amygdala).     

Interaction between neurons of the frontal cortex and hippocampus during the realization of choice of food reinforcement quality in cats

Six cats were subjected to the procedure of appetitive instrumental conditioning (with light as a conditioned stimuls) by the method of the "active choice" of reinforcement quality. Short-delay conditioned bar-press responses were rewarded with bread-meat mixture, and the delayed responses were reinforced by meat. The animals differed in behavior strategy: four animals preferred the bar-pressing with a long delay (the so-called "self-control" group), and two cats preferred the bar-pressing with a short delay (the so-called "impulsive" group). Multiunit activity in the frontal cortex and hippocampus (CA3) was recorded via chronically implanted nichrome wire semimicroelectrodes. An interaction between the neighboring neurons in the frontal cortex and hippocampus (within local neural networks) and between the neurons of the frontal cortex and hippocampus (distributed neural networks in frontal-hippocampal and hippocampal-frontal directions) was evaluated by means of statistical crosscorrelation analysis of spike trains. Crosscorrelations between neuronal spike trains in the delay range of 0-100 ms were explored. It was shown that the number of crosscorrelations between the neuronal discharges both in the local and distributed networks was significantly higher in the "self-control" cats. It was suggested that the local and distributed neural networks of the frontal cortex and hippocampus are involved in the system of brain structures which determine the behavioral strategy of animals in the "self-control" group.     

Role of dominant motivation in producing the effects of electric stimulation of hypothalamo-limbic structures

The experiments were made on cats with electrodes chronically implanted in the hypothalamus and the amygdala. The effects of electrical stimulation of the points from which the food reactions were initially evoked, were transformed into an avoidance reaction, if stimulation was applied in surroundings where the animals had previously received pain stimuli. Defensive reactions to stimulation of the hypothalamus and amygdala changed to alimentary reactions if the same stimulation was presented to hungry cats in conditions of repetitive feeding. A conclusion has been drawn that the elements of the hypothalamo-limbic structures have plastic properties and may be involved in different forms of behaviour, depending on current motivation and learning.     

Functional transswitching of dominant motivation in the systems organization of behavioral acts

In experiments on rabbits, instrumental and complex conditioned alimentary behaviour was studied at various ways of raising alimentary motivation to extreme levels. Animals behaviour in these conditions could acquire an outwardly non-motivated (in relation to alimentary need) character. It is suggested that these phenomena are based on the transformation of the dominant motivation and not on the mechanism of "shifted" activity. In experiments on rats, a long "pseudoreinforcement" of extremely enhanced motivation of thirst by ethanol led to profound changes of physiological and neurochemical properties of the primary drinking motivation centres of the hypothalamus. It is suggested that such changes underlie the realization of plasticity properties of the dominant motivation.     

The interrelations between neurons of the amygdala and hypothalamus during conditioning with selection of food reinforcement quality in cats

Three cats were subjected to appetitive instrumental conditioning to light by the method of the "active choice" of the reinforcement quality. The short-delayed conditioned bar-pressings were reinforced by bread-meat mixture and the delayed response by meat. The animals differed in behavior strategy: two animals preferred bar-pressing with long delay (the so-called "self-control" group) and one animal preferred bar-pressing with short delay (the so-called "impulsive" group). The multiunit activity of the basolateral amygdala and nucleus lateralis of the hypothalamus was recorded through chronically implanted nichrome wire semimicroelecrodes. The interactions between the neighboring neurons in the lateral hypothalamus and basolateral amygdala (within the local neuronal network) and between the neurons of the basolateral amygdala and lateral hypothalamus (distributed neuronal networks in the direction amygdala--hypothalamus and vice versa) were evaluated by means of statistical crosscorrelation analysis of spike trains. The crosscorrelational interneuronal connections in the delay range of 0-100 ms were examined. It was shown that the number of crosscorrelations between the discharges on neurons both in the local networks of basolateral amygdala and distributed networks was significantly higher in "impulsive" cats. In both groups of animals, the percentage of crosscorrelations between neighbouring neurons in the local networks of the lateral hypothalamus was similar. We suggest that the local networks of the basolateral amygdala and amygdalar-hypothalamic distributed neuronal networks are involved in the system of brain structures which determine the individual features of animal behavior.     

The possibility of elaborating conditioned reflexes on the basis of emotional reactions evoked by electrical stimulation of limbic structures]

In experiments on cats with chronically implanted electrodes a conditioned stimulus (200 c/s tone) was paired with electrical stimulation of limbic structures, which produces pronounced emotional behaviour: defensive, aggressive, alimentary or drinking reactions. It has been shown that conditioned reactions are not elaborated on the basis of electrical stimulation, which activates alimentary, drinking or aggressive behaviour. Neither is a conditioned reflex formed to the combination of sound and stimulation of the brain structures, which inhibits alimentary behaviour. A distinct conditioned fear reaction sets in as a result of combination of sound and electrical stimulation of brain structures, which evoke defensive behaviour. The data obtained are analyzed in the light of the significance of natural requirements of the organism for the elaboration of conditioned reflexes.     

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). Before the lesions the dogs were taught to receive food in two different feeders to conditioned stimuli with equally probable alimentary reinforcement. After ablation in the inter-trial intervals the dogs were running from the one feeder to another. In the answer to conditioned stimuli for many times the dogs choose the same feeder. The disturbance of the behavior after some times completely restored. In the experiments with competition of probability events and values of reinforcement the dogs chose the feeder with low-probability but better quality of reinforcement. In the experiments with equal value but different probability the intact dogs chose the feeder with higher probability. In our experiments the dogs with prefrontal lesions chose the each feeder equiprobably. Thus in condition of free behavior one of different functions of the prefrontal cortex is the reactions choose with more probability of reinforcement.     

Electrophysiologic analysis of the conditioned reflex activity of cats against a background of thirst

EEG of the cerebral cortex and hypothalamic electrogram of cats during salt load and water deprivation were recorded at performance of conditioned running elicited by signals of insipid and salt food. The signal of insipid food presented during thirst was accompanied only by the cerebral cortex activation, while the salt signal involved in activation not only the cortex but the hypothalamus as well. In cases when the insipid signal was reinforced by salt food and the animal ate it (though during thirst it rejected the food), strong cortex activation was observed with the involvement of paraventricular parts of the hypothalamus. During intense thirst reversal was obtained of the signal role of the conditioned cue in accordance with the new quality of the alimentary reinforcement. Hypothalamo-cortical mechanisms of dominant motivation and its conditioned provision are discussed.     

Influence of blockade of the dopaminergic D1/D2 receptors on choice behaviour at different by validity reinforcements in cats

The influence of two selective antagonists of the dopaminergic receptors, raclopride (D2) and SCH 23 390 (D1) on behavior of "impulsive" and "self-controlled" cats was similar directed. A selective blockade of the dopaminergic D1/D2 receptors by use of raclopride and SCH 23 390 changed a behavioural choice strategy of two different by validity and delay reinforcements in impulsive cats, but did not change it substantially in "self-controlled" animals. Increase of doses of raclopride and SCH 23 390 led to decrease of a part of the short-latency and increase of a part of the long-latency reactions (pedal pressings) in a total number of all effective responses. This occurred only in "impulsive" animals, that indicates probably the decrease of impulsive properties of their behaviour. Both compounds did not affect the choice strategy (a low quality immediate vs. a high quality delayed reinforcements) in "self-control" animals, but elicited more errors and inhibitory responses in their behavior. The data obtained are not consistent with the "dopamine" hypothesis, which predicts increase of impulsivity under influence of dopaminergic antagonists. The reasons that might lead to the data obtained are discussed.     

The model of the reward choice basing on the theory of reinforcement learning

We developed the model of alimentary instrumental conditioned bar-pressing reflex for cats making a choice between either immediate small reinforcement ("impulsive behavior") or delayed more valuable reinforcement ("self-control behavior"). Our model is based on the reinforcement learning theory. We emulated dopamine contribution by discount coefficient of this theory (a subjective decrease in the value of a delayed reinforcement). The results of computer simulation showed that "cats" with large discount coefficient demonstrated "self-control behavior"; small discount coefficient was associated with "impulsive behavior". This data are in agreement with the experimental data indicating that the impulsive behavior is due to a decreased amount of dopamine in striatum.     

Participation of peptides in processes involved in the development of alimentary motivation in the rabbit

On the base of behavioural and electrophysiological experiments it was suggested that in rabbits the realization of the dominant feeding motivation into the goal-directed behaviour implied at the molecular-genetical level the operative synthesis of gastro-intestinal neuropeptide gastrin or its derivatives. It was supposed that the suppression of genetic information realization in CNS under blocking of peptide synthesis led to impossibility of goal-directed alimentary behaviour organization. This mechanism was found to be specific for alimentary behaviour; any its connection with defensive motivation realization was not observed.     

Individual behavior characteristics of dogs in conflict between the probability and the quality of reinforcement

In experiments on dogs with equiprobable right and left reinforcements in the choice of feeder in conditions of free behaviour, direct correlation was found between the strength of the nervous system and the strategy of dogs behaviour. The dogs of strong type, despite the difference in equilibration and lability, manifested one, similar strategy of behaviour with dominating preferences, definite and goal-directed actions; the dogs of the weak type displayed another strategy, characterized by uncertainty, permanent hesitations in choice reaction. In situation of competition of probability and value of reinforcement, some different aspects of animals typology appeared, presumably connected with individual characteristics of functioning of four brain structures as a basis of types of higher nervous activity (frontal cortex, hippocampus, amygdala, hypothalamus). Behaviour of choleric and flegmatic was oriented to a high probability of events and that of sanguinic and melancholic--to a low one. Thus, "informational" and "motivational" factors of behaviour organization are connected with interaction of specialized brain macrostructures, and properties of this interaction become apparent in animals typology.     

The individual organization of frontal-hippocampal networks during realization of different behavioral tasks

Four cats were subjected to appetitive instrumental conditioning with light as a conditioned stimulus by the method of "active choice" of the reinforcement quality: short-delay conditioned bar-press responses were followed by bread-meat mixture and the delayed responses--by meat. The animals differed in behavior strategy: four animals preferred bar-pressing with long delay (so called "self-control" group); two animal preferred bar-pressing with short-delay (so called "impulsive" group). Then all the animals were learned to short-delay (1 s) instrumental conditioned reflex to light (CS+) reinforced by meat. The multiunit activity in the frontal cortex and the hippocampus (CA3) was recorded through chronically implanted nichrome-wire semimicroelectrodes. The interactions among the neighboring neurons in the frontal cortex and hippocampus (within the local neuronal networks) and between the neurons of the frontal cortex and hippocampus (distributed neuronal networks of frontal-hippocampal and hippocampal-frontal directions) were evaluated by means of statistical crosscorrelation analysis of the spike trains. Crosscorrelation interneuronal connections in the delay range 0-100 ms were explored. It was shown that the functional organization of the frontal and hippocampal neuronal networks differed in choice behavior and was similar during realization of short-delayed conditioned reflex. We suggest that the local and distributed neural networks of the frontal cortex and hippocampus take part in the realization of cognitive behavior, in particularly in the processes of the decision making.     

Ensemble activity of visual and frontal cortex in the conditions of choice of different value food reinforcement in cats

The method of "low choice" of food value reinforcement depending on delayed response to its reception demonstrated various strategy of behaviour, showing short or delayed responses of pressing pedal for reception of low or high value of food reinforcement. In trained cats, multiunit activity was recorded in investigated brain areas and functional interneuron interactions were subsequently analysed. Significant prevalence of interneuron interactions was revealed in "impulsive" animals in both cortical zones as well as intergroup differences during the pre-signal and signal periods in visual and frontal cortex.     

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. During of choice series defensive reactions were dominated in two dogs, alimentary reactions--three of them. For restoration alimentary behaviour in dog with great dominating of defensive reactions were many times reinforced with--food "passive" pressing legs on pedal during conditional stimuli, dog with less dominating of these reactions for restoration were enough a few coupling of conditional stimuli with food. With intensification electrocutaneus stimulation of legs or decreasing alimentary reinforcement we a success of diminishing of degree of alimentary reaction domination in one dog and in other ones temporarily changed of these domination on prevalence of defensive reactions. The results were compared with data, obtained in these dogs with technique of choice between probability and value of alimentary reinforcement. This comparison were permitted us of ranging dogs on scale "carefulness-riskiness", revealed of individual typological features of these animals.     

A statistical analysis of the functional connections between the neurons of the visual and motor cortex in different forms of conditioned-reflex behavior]

In experiments on cats with elaboration of delayed alimentary operant reflexes to light organization was studied of interneuronal cortical connections. By means of cross-correlation analysis the dynamics of intra- and interstructural neuronal network was revealed at the level of cortical projections (visual and motor) of cats brain zones at three forms of behaviour: CR realization, in intersignal period with the presence and absence of operant movements. Depending on the forms of behaviour, predominance of "informational" or "motivational" interneuronal connections was observed.     

The role of the lateral and medial hypothalamus in reproducing a motor reaction as the signal during the acquisition of classical conditioned reflexes]

In experiments on three dogs there was shown that testing electrostimulation of the lateral hypothalamus reproduced the motor reaction which is a signal stimulus at elaboration of classic alimentary conditioned reflexes (CRs) and did not reproduce it at elaboration of classic defensive CR. Testing electrostimulation of medial parts of the hypothalamus reproduced, as LH electrostimulation the "signal" motor reaction, but in less percentage of cases, during elaboration of classic alimentary CRs and did not reproduce it at elaboration of classic defensive CRs. The reproduction of the signal motor reaction at LH electrostimulation is connected with activation of backward conditioned connection from motivation structures of the hypothalamus to representation of the signal stimulus in the motor cortex.     

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. Later on, alternative experiments with choice between reinforcements were carried out. In both of experimental series, the degree of alimentary excitability (hunger, satiation) was changed. Numbers of responses to differential and positive conditioned stimuli and their latencies were calculated. Under condition of choice (electrodes on a leg and a pedal in front of a dog) the response depended on a dominant motivation. The dogs differed in the degree of motivation dominance. Differential inhibition was less perfect in unalterable experimental series with dominant motivation. Under conditions of choice between alimentary and defensive reinforcements, the response to the differential stimuli depended on the balance between these motivations: two days of hunger increased the number of alimentary responses, defensive responses prevailed after satiation.     

Significance of motivation balance for a choice of dog's behavior under conditions of environmental uncertainty

Two experimental models with a choice between two reinforcements were used for assessment of individual typological features of dogs. In the first model dogs were given the choice of homogeneous food reinforcements: between less valuable constantly delivered reinforcement and more valuable reinforcement but delivered with low probabilities. In the second model the dogs had the choice of heterogeneous reinforcements: between performing alimentary and defensive reactions. Under conditions of rise of uncertainty owing to a decrease in probability of getting the valuable food, two dogs continued to prefer the valuable reinforcement, while the third animal gradually shifted its behavior from the choice of a highly valuable but infrequent reward to a less valuable but easily achieved reinforcement. Under condition of choice between the valuable food reinforcement and avoidance of electrocutaneous stimulation, the first two dogs preferred food, whereas the third animal which had been previously oriented to the choice of the low-valuable constant reinforcement, steadily preferred the avoidance behavior. The data obtained are consistent with the hypothesis according to which the individual typological characteristics of animals's (human's) behavior substantially depend on two parameters: extent of environmental uncertainty and subjective features of reinforcement assessment.