Synchronization of Independent Neural Ensembles in Human EEG during Choice Tasks.

During behavioral experiments, humans placed in a situation of having to choose between a more valuable but risky reward and a less valuable but guaranteed reward make their decisions in accordance with external situational factors and individual characteristics, such as inclination to risk or caution. In such situations, humans can be divided into "risk-inclined" and "risk-averse" (or "cautious") subjects. In this work, characteristics of EEG rhythms, such as phase-phase relationships and time lags between rhythms, were studied in pairs of alpha-beta and theta-beta rhythms.

[Impulsive Choice Improves the Cue Memory at an 8-arms Radial Maze Learning in Rats].

At the process of learning in an 8-arm radial maze the impulsive animals found the reinforced arms and ate the pellets faster, than self-control and ambivalent rats. They committed less working memory errors at the cue memory task, though there was no difference in the rate of learning and a number of errors of reference memory in animals of different groups. During reversion learning at the change of reinforced arms on unre- inforced, and vice versa, the impulsive animals spent less time to enter into the reinforced arms compared to other groups.

[Does Impulsivity Affect a Long-term and Working Memory in rats?].

In the present paper usingthe method of delay discounting three groups of animals were discovered: a) those that at choice between immediate weak and delayed strong rewards have chosen an immediate reinforcement (high impulsive rats); b) those that were able to inhibit its own behavior and get the delayed reinforcement (low impulsive rats); and c) the rats with both types of reactions. In the water maze the different groups of rats did find a hidden platform for different time, swum various distance and with different speed. The differences however were significant only at overall comparison (for all days and trials) of the above mentioned parameters of the water maze learning.

[Effect of Agonists and Antagonists of α2 Adrenergic Receptors on Choice of Reinforcement Value in Rats with Different Levels of Impulsivity].

The influence of drugs, agonist (clonidine) and antagonist (yohimbine) of α2-adrenergic receptors 5-HT2 on the behavior of rats tested by the method of choice to the value of reinforcement was investigated. Based on the selection of a rat the pedal for immediate poor and delayed valuable reinforcement rats were divided into 3 groups. Rats, in most cases, choosing valuable delayed reinforcements were classified as low-impulsive, those who mainly chosen poor immediate reinforcement to the high-impulsive group.

[Single and Network Neuron Activity of Subthalamic Nucleus at Impulsive and Delayed (Self-Control) Reactions in Choice Behavior].

During our experiments on cats was investigated the subthalamic neuron activity at different types of behavior in case of reinforcement choice depending on its value and availability. In chronic experiences the multiunit activity in subthalamic nucleus (STN) and orbitofrontal cortex (FC) has been recorded. Multiunit activity was analyzed over frequency and network properties of spikes.

[Evaluation of exploratory activity and anxiety in rats with different levels of impulsive behavior].

Rats were divided into 3 groups according to their preference for reinforcements of different values. Animals that preferred valuable but delayed reinforcement in more than 70% of cases formed as self-controlled group, less than 30% of cases formed an impulsive group, the rest formed an ambivalent group. Behavior of animals of different groups was scored for exploratory activity and anxiety in x-maze, fear-conditioning and novelty suppressed feeding.

[Behavioral effects during the local activation and blockade of serotonin and dopamine receptors in the frontal cortex in cats in the model with a choice of reinforcements of different value].

In the model with a choice of reinforcements of different value animals were able to "impulsive" and "self-controlled" behavior with an equal probability. Five adult cats were tested. A local application of agonists of 5-HT(1A) and 5-HT(2A/C) receptors (8-OH-DPAT, DOI) in the frontal cortex have resulted in a significant decrease of the "impulsive" reactions and an increase of omissions.

[Neuron activity of cortex and striatum at animals in the situation with "right of choice" of reinforcement].

In behavior model of "right of choice" of value of appetitive reinforcement animals have classified in self-control, ambivalent and impulsive groups based on significant distinctions in displays of short delayed or long delayed reflexes. The organization of functional cross correlation interneuron interactions in frontal, visual, motor cortical areas and dorsal part of caudatus have estimated at realization short delayed, long delayed reflexes and errors. Similarity and distinctions in the organization of network activity were analyzed.

[Effect of agonists and antagonists of 5-HT2 receptors on rats with different choice of reinforcement value].

The influence of drugs, agonist (DOI) and antagonist (ketanserin) ofserotonin receptors 5-HT2 on the behavior of rats tested by the method of choice to the value of reinforcement was investigated. Depending on their preferences in food reinforcement rats were divided into self-control (choosing more valuable, delayed reinforcement) and impulsive (low value, immediate reinforcement) groops. An hour before the test animals were administrated i.

[Network activity of frontal and motor cortex in situations of simple and difficult decision-making in cats].

The organization of frontal and motor cortex network activity in situations with simple (without a choice) and difficult decision-making when there is a possibility of behavior choice strategy is shown. At development of delay reflexes with one reinforcement (without a choice) animals did not differ on behavior and showed high criterion of right answers. The strategy of behavior of the same animals in the complicated situation, with "right" choice food reinforcement, was different and animals showed different abilities of problem solution.

[Effect of D1/D2 dopamine receptors agonists and antagonists on rats with different choice of reinforcement value].

The effects of D1/D2 dopamine receptors agonist (SKF, TNPA) and antagonist (SCH 23390, raclopride) on rat behavior, associated with the choice of the reinforcement value were investigated. Animals were divided into two typological groups--group of impulsive, choosing low-value immediate reinforcement, and self-control group, preferring valuable delayed reinforcement (paradigm delay-discount). The results showed that i.

[Effect of the selective ligands 5-HT(1A) receptors administration on the impulsive and self-control behavior in rats].

The influence of drugs, agonist and antagonist of serotonin receptors 5-HT(1A) on the behavior of rats tested by the method of choice to the value of reinforcement was investigated. Depending on their preferences in food reinforcement rats were divided into self-monitoring (choosing more valuable, delayed reinforcement) and impulsive (low value, immediate reinforcement). An hour before the test animals were administrated i.

[Ensemble activity of neurons in the visual, frontal, and sensorimotor cortices and dorsal striatum during actualization of behavioral program under conditions of strategy choice].

Unit and network activity of neurons in the visual, sensorimotor, and frontal cortical areas and dorsal striatum was investigated in cats under conditions of choice of the reinforcement value depending on its delay. The animals did not differ from each other in behavior. After immediate or delayed responses cats got low- or highly-valuable reinforcement, respectively.

[Effects of blockade of dopaminergic D1/D2 receptors on behavior of impulsive and self-controlled rats].

Selective antagonists of D1 and D2 receptors (SCH 23 390 and raclopride respectively) were injected to rats divided on the basis of preliminary experiments into groups of"self-controlled" (preference of valuable but delayed reinforcement) and "impulsive" (choice of less valuable but immediate reinforcement) animals. Number of omissions of reactions and their latencies were recorded. In "self-controlled" rats, both drugs increased the number of reactions for less valuable immediate reinforcement, i.

[Displays of individually-typological features of animals and the person at a choice of strategy of goal-direction behavior].

In work the hypothesis according to which different forms of goal-directed behavior develop depending on the basis of the undervaluation/supervaluation of reinforcement by brain abilities at the conditions of its achievement uncertainty. From these positions such opposite biological characteristics of the subject, as impulsiveness/self-control, care/propensity to risk on which basis there are individually typological features in behavior of the person and animals are considered. In the article, our experimental data on animals and the persons by behavioral techniques and results of last years on research of neural networks of animal cortical and subcortical brain structures depending on the strategy in choice behavior are also analyzed.

[Differences in behavior of impulsive and self-controlled rats in the open-field and light-dark tests].

The aim of the study was to reveal the relationship between impulsive behavior in rats, on the one hand, and locomotor activity and emotionality on the other hand. Rats were divided into groups according to their preference for reinforcements of different values. Animals that preferred valuable but delayed reinforcement in more than 60% of cases formed a self-controlled group, whereas rats that selected poor but immediate reinforcements in more than 60% of the cases were considered as impulsive.

[Individual typological differences in human behavior under conditions of reward choice assoicated with risk].

A choice between probability (100, 75, 50, 25, 10, 0%) and valuable reward were investigated in adult. In behavioral experiments, adult subjects put in a situation of a choice between greater, but risky prize and smaller, but received always, made the decision according to situational factors and specific features of character such as propensity to risk and care. In a situation of choice of behavioral strategy, subjects could be divided in "inclined to risk" and "careful".

[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 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).

[Effects of blokade of the dopaminergic D1/D2 receptors on the single and network neuronal activity in the frontal and visual cortices and behavior of cats].

The results obtained at the levels of single and network neuronal activity in the frontal and visual cortices of cats with different types of behavior revealed features of activity of these structures in normal conditions and after local introductions of antagonists of DI/D2 receptors (SCH23390 and raclopride) into the n. accumbens and frontal cortex. Under the influence of the antagonists, long-latency reactions were characterized by a significant increase in the average frequency of neuronal activity in the frontal cortex, whereas in the visual cortex the average frequency decreased as compared to norm.

[Investigation of behavior of "impulsive" and "self-controlled" animals by the method of "emotional resonance"].

Rats divided into groups of "impulsive" and "self-controlled" animals by their preference of either high valuable but delayed or a low valuable but immediate food reward were studied by the method of "emotional resonance". It was shown that all rats of the "self-controlled" group choosing a high valuable although delayed reinforcement did not escape the defensive signals of another animal of the same species and for the most part of the trial time preferred to stay in the dark "house". The majority of animals belonging to the "impulsive" group (80%) spent more than a half of the time of the experiment in the bright compartment and thus saved a partner from electrical stimulation.

[Study of impulsivity in rats under conditions of choice between food reinforcements of different values].

Rat behavior was studied under conditions "with the right to choose the values of reinforcements depending on the time delay of its receipt". Rats were placed in a chamber equipped with two retractable pedals, pressing one of which provided a small portion of food (1 pellet), and pressing the second pedal was followed by the delivery of more valuable food (4 pellets), but delayed reinforcement. Rats preferring small reinforcement without the delay were considered as "impulsive" and rats choosing more valuable delayed reinforcement were considered as "self-controlling".

[Functional connectivity of neurons of the frontal cortex and hippocampus under conditions of cholinergic deficit during choice behavior].

In cat experiments under conditions of choice between two different strategies of the instrumental behavior (impulsive and self-controlling), functional connectivity of neurons in the frontal cortex, hippocampus and between them was assessed on the basis of the analysis of wide and narrow peaks of cross correlation histograms of several spike series and their number. The functional connectivity of neurons in the above mentioned structures was better expressed in self-controlling cats than in animals with mixed impulsive/self-controlling reactions. On the contrary, the influence of an outer source assessed by the number of the wide peaks of cross correlation histograms was more pronounced in cats with mixed impulsive/self-controlling reactions.

Cooperative activity of neurons in the nucleus accumbens and frontal cortex in cats trained to select reinforcements of different value.

Results obtained at the level of the organization of interneuronal interactions of cells in the nucleus accumbens and frontal cortex revealed the features of the involvement of this component in "impulsive" and "self-controlled" behavior, consisting of an increase in bidirectional interactions between the structures of interest, accompanied by simultaneous reductions in the regularity of interactions with increases in "impulsivity" and decreases in "self-control." Long-latency reactions appearing only in "impulsive" animals were associated with decreases in the control of frontal cortex cells by the nucleus accumbens during the signal period, which correlated with the low activity of the network activity of the nucleus accumbens in these animals. Comparison of the patterns of frontal-accumbens interactions as the animals performed a single type of activity demonstrated that the connections in neuron pairs during the presignal and signal periods were similar, while significant differences in patterns were seen during the performance of different types of activity.

Organization of interneuronal connections in the nucleus accumbens in "impulsive" and "self-controlled" behavior in cats.

In behavioral experiments, cats placed in a situation of choosing between a high-value time-delayed and a low-value rapid food reinforcement elected to wait for the preferred reward (they demonstrated "self-control") or to obtain the worse reward quickly (they demonstrated impulsive behavior). On the basis of the selected behavioral strategy, the cats were divided into three groups - "impulsive," "ambivalent," and "self-controlled." Cross-correlation analysis was used to assess the linked activity of cells in the nucleus accumbens, which reflects the nature of interactions between close-lying neurons.