[The ethical aspects of physiological experiment].

A modern classification of invasive procedures developed according to International Bioethical Principles has been presented. The experimental data convincingly demonstrate that using of noninvasive approaches and techniques give a good opportunity to reduce a number of animals recruited in experiment as well as to keep the normal (not distressful) physiological functions of animals. The data presented stress that development of noninvasive techniques is closely related both to scientific and social aspects of our life, allowing the scientists to provide high validity of experimental data obtained as well as to keep themselves as a human beings.

Involvement of the nucleus accumbens in the formation of spatial selection reactions in rats in a radial maze.

Studies on rats demonstrated that lesioning of the medial shell of the nucleus accumbens led to impairment of the ability of experimental rats to perform error-free identification of the arm containing the largest amount of reinforcement in a radial maze. The behavioral deficit was not associated with impaired motivation or sensorimotor learning ability, as there was no such deficit in operated rats during sequential presentation of local discriminant stimuli identifying the location of the forthcoming reinforcement. These data suggest that the medial shell of the nucleus accumbens, which receives convergent projections from the ventral hippocampus, amygdala, and ventral tegmental area, plays an important role in organizing the spatial orientation of the animal in the direction of the preferred reinforcement in conditions of a sensory information deficit.

[Participation of the nucleus accumbens in acquisition of spatial choice behavior in rats performing in a radial plus maze].

The role of medial shell of the nucleus accumbens in acquisition of spatial behavior was studied in rats performing choice task in radial maze with asymmetrical water reinforcement. It has been found that the nucleus accumbens lesioned rats failed in finding larger rewards but preserve their reward-seeking behavior guided by visual discriminative stimuli. The results obtained are in good agreement with suggestion that the nucleus accumbens is a site of convergence of spatial information (from hippocampus) with reward information (from amygdala and VTA), providing bridge for effective limbic-motor interface underlying motivated goal-directed behavior in animals.