title: Effects of sex and gonadectomy on social investigation and social recognition in mice.
abstract: BACKGROUND
  An individual's ability to recognise and pay attention to others is crucial in order to behave appropriately in various social situations. Studies in humans have shown a sex bias in sociability as well as social memory, indicating that females have better face memory and gaze more at the eyes of others, but information about the factors that underpin these differences is sparse. Our aim was therefore to investigate if sociability and social recognition differ between female and male mice, and if so, to what extent gonadal hormones may be involved. Intact and gonadectomised male and female mice were assessed for sociability and social recognition using the three-chambered sociability paradigm, as well as the social discrimination test. Furthermore, we conducted a novel object recognition test, a locomotor activity test and an odour habituation/dishabituation test.
  
  
  RESULTS
  The present study showed that the ability to recognise other individuals is intact in males with and without gonads, as well as in intact females, whereas it is hampered in gonadectomised females. Additionally, intact male mice displayed more persistent investigatory behaviour compared to the other groups, although the intact females showed elevated basal locomotor activity. In addition, all groups had intact object memory and habituated to odours.
  
  
  CONCLUSIONS
  Our results suggest that intact male mice investigate conspecifics more than females do, and these differences seem to depend upon circulating hormones released from the testis. As these results seem to contrast what is known from human studies, they should be taken into consideration when using the three-chambered apparatus, and similar paradigms as animal models of social deficits in e.g. autism. Other behavioural tests, and animal models, may be more suitable for translational studies between patients and experimental animals.
authors.affiliation: Department of Pharmacology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden. sara.karlsson@neuro.gu.se.
authors.forename: Sara A
authors.initials: SA
authors.lastname: Karlsson
authors.affiliation: Department of Pharmacology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden. kalt.haziri@gmail.com.
authors.forename: Kaltrina
authors.initials: K
authors.lastname: Haziri
authors.affiliation: Department of Pharmacology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden. evelynhansson@gmail.com.
authors.forename: Evelyn
authors.initials: E
authors.lastname: Hansson
authors.affiliation: Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden. petronella.kettunen@neuro.gu.se.
authors.forename: Petronella
authors.initials: P
authors.lastname: Kettunen
authors.affiliation: Department of Pharmacology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden. lars.westberg@pharm.gu.se.
authors.forename: Lars
authors.initials: L
authors.lastname: Westberg
mesh_terms: D000818:Animals; D004192:Discrimination, Psychological / Q000502:physiology; D005260:Female; D042341:Gonadal Hormones / Q000378:metabolism*; D006185:Habituation, Psychophysiologic / Q000502:physiology; D008297:Male; D008810:Mice, Inbred C57BL / Q000502:physiology* / Q000523:psychology*; D023421:Models, Animal; D055696:Olfactory Perception / Q000502:physiology; D009919:Orchiectomy; D010052:Ovariectomy; D011581:Psychological Tests; D021641:Recognition, Psychology / Q000502:physiology*; D012727:Sex Characteristics; D012919:Social Behavior
chemical_list: D042341:Gonadal Hormones