An experimental approach to the study of teamed aggression

The sensory contact technique increases aggressiveness in male mice and all ows aggressive types of behavior to be formed as a result of the repeated e xperience of victories in daily agonistic confrontations. Some behavioral d omains confirm the development of learned aggression in males similar to th ose in humans, The features are repeated experience of aggression reinforce d by victories; elements of learned behavior after periods of confrontation ; intent, measured by increase of the aggressive motivation prior to agonis tic confrontation; and decreased emotionality, estimated by parameters of o pen-field behavior. Relevant situation provokes increases in aggression (bo undary aggression). This review summarizes data on the influence of positiv e fighting experience in daily intermale confrontations on the behavior, ne urochemistry, and physiology of aggressive mice (winners). This sort of exp erience changes many characteristics in individual and social behaviors, th ese having been estimated in different tests and in varied situations. Some physiological parameters are also changed in the winners. Neurochemical da ta confirm the activation of brain dopaminergic systems and functional inhi bition of serotonergic system in winners under the influence of the repeate d experience of aggression. The expression of the neurochemical and behavio ral changes observed in winners has been found to depend on the mouse strai n and on the duration of their agonistic confrontations. (C) 2000 Wiley-Lis s, Inc.