Agonistic behavior: a model, experimental studies, and perspectives

Agonistic (competitive) behavior includes the manifestations of aggression and submissiveness by individuals in conflict situations and is a universal form of behavior found in animals of different species. The sensory contact model allows aggressive and submissive (inhibited, suppressed) types of behavior to be formed in male mice as a result of acquisition of repeated experience of social conquests or defeats in daily aggressive interactions. Chronic experience of aggression is accompanied by total activation of the dopaminergic systems in the victors. At the same time, experience of social defeat leads to changes in the state of the serotoninergic and noradrenergic systems of various parts of the brains of the defeated animals. As a consequence, significant differences in emotional expression, movement activity, investigative activity, communicative ability, alcohol consumption, and many physiological aspects were found in animals of opposite social groups. The extent and nature of these changes depended on the type of social behavior formed by the animals (victors, vanquished), the duration of confrontational experience, and the genetically determined characteristics of the animals (i.e., which line of mice). The possibilities and perspectives of this model of sensory contact in medical-biological and basic investigations is discussed.