Unconditioned anxiety and social behaviour in two rat lines selectively bred for high and low anxiety-related behaviour - Henniger,M.SH.; Ohl,F.; Hölter,S.M.; Weissenbacher,P.; Toschi,N.; Lörscher,P.; Wigger,A.; Spanagel,R.; Landgraf,R. (Behav Brain Res, 2000)