title: The neural background of hyper-emotional aggression induced by post-weaning social isolation.
abstract: Post-weaning social isolation in rats is believed to model symptoms of early social neglect-induced externalizing problems including aggression-related problems. We showed earlier that rats reared in social isolation were hyper-aroused during aggressive contacts, delivered substantially more attacks that were poorly signaled and were preferentially aimed at vulnerable body parts of opponents (head, throat and belly). Here we studied the neural background of this type of aggression by assessing the expression of the activation marker c-Fos in 22 brain areas of male Wistar rats submitted to resident-intruder conflicts. Post-weaning social isolation readily produced the behavioral alterations noticed earlier. Social isolation significantly increased the activation of brain areas that are known to directly or indirectly control inter-male aggression. Particularly, the medial and lateral orbitofrontal cortices, anterior cingulate cortex, bed nucleus of the stria terminalis, medial and basolateral amygdala, hypothalamic attack area, hypothalamic paraventricular nucleus and locus coeruleus showed increased activations. This contrasts our earlier findings obtained in rats with experimentally induced hypoarousal, where abnormal attack patterns were associated with over-activated central amygdala, lateral hypothalamus, and ventrolateral periaqueductal gray that are believed to control predatory attacks. We have observed no similar activation patterns in rats socially isolated from weaning. In summary, these findings suggest that despite some phenotypic similarities, the neuronal background of hypo and hyperarousal-associated abnormal forms of aggression are markedly different. While the neuronal activation patterns induced by normal rivalry and hypoarousal-driven aggression are qualitative different, hyperarousal-associated aggression appears to be an exaggerated form of rivalry aggression.
authors.affiliation: Institute of Experimental Medicine, Department of Behavioral Neuroscience, P.O. Box 67, H-1450 Budapest, Hungary. toth.mate@koki.hu
authors.forename: Mate
authors.initials: M
authors.lastname: Toth
authors.forename: Aron
authors.initials: A
authors.lastname: Tulogdi
authors.forename: Laszlo
authors.initials: L
authors.lastname: Biro
authors.forename: Petra
authors.initials: P
authors.lastname: Soros
authors.forename: Eva
authors.initials: E
authors.lastname: Mikics
authors.forename: Jozsef
authors.initials: J
authors.lastname: Haller
mesh_terms: D000374:Aggression / Q000502:physiology; D000818:Animals; D000831:Animals, Newborn; D001921:Brain / Q000033:anatomy & histology* / Q000378:metabolism*; D001931:Brain Mapping; D004644:Emotions / Q000502:physiology*; D008297:Male; D008959:Models, Neurological; D009474:Neurons / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012934:Social Isolation / Q000523:psychology*; D018709:Statistics, Nonparametric; D014886:Weaning
chemical_list: D016760:Proto-Oncogene Proteins c-fos