animal cell 4 animal experiment 4 animal tissue 4 controlled study 4 hypothalamus 4 nonhuman 4 pretectum 4 Aggression 2 Amphibia 2 Animals 2 Anura 2 Article 2 Brain 2 Bufo arenarum 2 Cichlasoma dimerus 2 Cichlids 2 Development 2 Diet 2 Female 2 Gonadal Steroid Hormones 2 Hierarchy, Social 2 Hydrocortisone 2 Immunoenzyme Techniques 2 L-Tryptophan 2 Male 2 Nervous system 2 Neuropeptide 2 Pituitary 2 Serotonin 2 Sexual Behavior 2