Interindividual variability in Swiss male mice: relationship between social factors, aggression, and anxiety.
In the present study we carried out a series of experiments in Swiss albino male mice to investigate a) the effects of previous social experience on the levels of anxiety in the elevated plus-maze (EPM) and b) whether the response of males in the EPM differs in relation to the different social status. In Experiment 1 we tested in the EPM male mice that received different social experience. Results showed that individually housing generally increased measures of anxiety in the EPM compared with the group-housing condition. Moreover, aggressive males, screened during dyadic encounters in a neutral cage, displayed the highest levels of anxiety relative to the other experimental conditions. In Experiment 2 male mice remained group-housed and were observed to record their social status. Results showed that those animals rated as socially dominant displayed a higher level of EPM anxiety relative to subordinates. From an ethological perspective our findings may be interpreted in terms of coping strategies, with aggressive/dominant animals typified by higher levels of risk assessment and open-arm avoidance than defensive/subordinate animals.
Ferrari
P F
PF
Dipartimento di Biologia Evolutiva e Funzionale, Università di Parma, Italy. labeto@biol.unipr.it
Palanza
P
P
Parmigiani
S
S
Rodgers
R J
RJ
D000374:Aggression / Q000523:psychology*; D000818:Animals; D001007:Anxiety / Q000523:psychology*; D001143:Arousal; D001362:Avoidance Learning; D004291:Dominance-Subordination; D006608:Hierarchy, Social; D007206:Individuality; D008297:Male; D018782:Maze Learning; D051379:Mice; D009043:Motor Activity; D012931:Social Environment