Acute and Chronic Lipopolysaccharide-Induced Stress Changes Expression of Proinflammatory Cytokine Genes in the Rat Brain Region-Specifically and Affects Learning and Memory.

Goal of the current work was to conduct comparative analysis of the effects of acute and chronic lipopolysaccharide-induced stress on the behavior of rats in the Morris water maze test and on expression of mRNA of proinflammatory cytokines and BDNF in different brain structures. Relevance of this study is related to poor understanding of the effects of acute and chronic stress on manifestation of cognitive brain functions, as well as ambiguity of the literature data on the effects of both stresses on hypothalamic pituitary axis and expression of the proinflammatory cytokine genes. In the experiments with rats, acute lipopolysaccharide (LPS)-induced stress improved learning in the Morris water maze.

[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.

[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.

[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.

[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.

[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.

[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.