Neural Connections of the Anterior Hypothalamus and Agonistic Behavior in Golden Hamsters

Abstract

In male golden hamsters, offensive aggression is regulated by an interaction between arginine-vasopressin and serotonin at the level of the anterior hypothalamus. The present studies were conducted to study a neural network underlying this interaction. The connections of the anterior hypothalamus were examined by retrograde and anterograde tracing in adult male hamsters. Several limbic areas were found to contain both types of tracing suggesting reciprocal connections with the anterior hypothalamus. Their functional significance relating to the consummation of aggression was tested by comparing neuronal activity (examined through quantification of c-Fos-immunolabeling) in two groups of animals. Experimental animals were sacrificed after attacking an intruder. Control animals were sacrificed after exposure to a woodblock carrying the odor of an intruder that elicited behaviors related to offensive aggression without its consummation. An increased density of Fos-immunoreactivity was found in experimental animals within the medial amygdaloid nucleus, ventrolateral hypothalamus, bed nucleus of the stria terminalis and dorsolateral part of the midbrain central gray. These data suggest that these areas are integrated in a neural network centered on the anterior hypothalamus and involved in the consummation of offensive aggression. Finally, c-Fos-immunoreactivity was combined with labeling of serotonin and vasopressin neurons to identify sub-populations particularly associated with offensive aggression. Vasopressin neurons in the nucleus circularis and medial division of the supraoptic nucleus showed increased neuronal activity in the fighters, supporting their role in the control of offensive aggression.

Neural responses to aggressive challenge correlate with behavior in nonbreeding sparrows

“…In addition, the present experiments provide novel data on Fos responses to STI and provide the first demonstration that aggressive behavior in birds correlates with IEG expression in the basal forebrain. Finally, we observed a pattern of IEG response that is consistent with patterns of IEG response that have been observed in rodents [19][20][21], suggesting that neural circuitry relevant to aggression has been strongly conserved during vertebrate evolution. A-E. Correlations between aggressive behavior (ln the number of barrier contacts during a 10-min observation) and Fos-ir cell counts in the ventral, ventrolateral and dorsal zones of the caudal lateral septum (LSc.v, LSc.vl and LSc.d; A-C, respectively), paraventricular hypothalamus (PVN; D), and anterior hypothalamus (AH; E) of male song sparrows exposed to a simulated territorial intrusion (n = 16).…”

“…In mammals, agonistic encounters elicit significant Fos responses within a similar suite of areas -the extended medial amygdala, LS (particularly the ventrolateral LS), AH, and lateral VMH/ ventrolateral hypothalamus [19][20][21]. Although these areas show increased IEG expression following agonistic encounters, it is not necessarily the case that these areas promote aggressive behaviors.…”

Low sex steroids, high steroid receptors: Increasing the sensitivity of the nonreproductive brain

“…The nT in birds is homologous to parts of the mammalian amygdala and previous work has shown that this region plays an important role in regulating sexual and aggressive behaviors in mammals and birds (Thompson et al, 1998;Delville et al, 2000;Davis and Marler, 2004;Reiner et al, 2004). Interestingly, in nT AR-mRNA expression was increased during the nonbreeding season.…”

Social instigation and repeated aggressive confrontations in male Swiss mice: analysis of plasma corticosterone, CRF and BDNF levels in limbic brain areas

“…10 The PFC and hippocampus have been identified as particularly important in the modulatory control of subcortical circuits that mediate aggressive and impulsive behaviors 11,12 ; the components of these circuits include the medial amygdala, hypothalamus and the periaqueductal grey. [13][14][15][16][17][18][19][20][21][22] Indeed, PFC lesions promote an increase in aggressive behavior in rats. 23 Similarly, lesions involving frontal and temporal brain areas have been demonstrated to dramatically increase aggressiveness in humans.…”