The corticomedial amygdala and learning in an agonistic situation in the rat

Bolhuis, Johan J.; FitzGerald, Rex; Dijk, Derk Jan; Koolhaas, Jaap M.

doi:10.1016/0031-9384(84)90311-1

Cited by 52 publications

(16 citation statements)

References 24 publications

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“…This pattern is in general agreement with previous results in the hamster, where restricted Fos activation also occurs in the anterodorsal and posterodorsal parts of the medial amygdalar nucleus (21-23), a result confirmed here for the rat (data not shown). The medial amygdalar nucleus plays a role in social recognition, including learning and memory for socially relevant cues (24,25), and the anteroventral and posterodorsal parts innervate directly the medial hypothalamic nuclei shown here to upregulate Fos in conspecific intruders (26). In contrast to parts of the medial hypothalamic circuit responsive to predatory threats, the functional role of medial hypothalamic parts activated in intruders during social agonistic encounters remains to be clarified.…”

Section: Discussionmentioning

confidence: 80%

Dissecting the brain's fear system reveals the hypothalamus is critical for responding in subordinate conspecific intruders

Motta¹,

Goto²,

Gouveia³

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

176

206

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Effective defense against natural threats in the environment is essential for the survival of individual animals. Thus, instinctive behavioral responses accompanied by fear have evolved to protect individuals from predators and from opponents of the same species (dominant conspecifics). While it has been suggested that all perceived environmental threats trigger the same set of innately determined defensive responses, we tested the alternate hypothesis that different stimuli may evoke differentiable behaviors supported by distinct neural circuitry. The results of behavioral, neuronal immediate early gene activation, lesion, and neuroanatomical experiments indicate that the hypothalamus is necessary for full expression of defensive behavioral responses in a subordinate conspecific, that lesions of the dorsal premammillary nucleus drastically reduce behavioral measures of fear in these animals, and that essentially separate hypothalamic circuitry supports defensive responses to a predator or a dominant conspecific. It is now clear that differentiable neural circuitry underlies defensive responses to fear conditioning associated with painful stimuli, predators, and dominant conspecifics and that the hypothalamus is an essential component of the circuitry for the latter two stimuli.defensive behavior ͉ dorsal premammillary nucleus ͉ periaqueductal gray A nimals have evolved a set of basic, genetically preprogrammed physiological responses and behaviors to ensure survival of individuals and of the species as a whole. Effective defense against threats in the environment is one obvious function essential for survival of the individual and is coordinated by the brain. A simple explanation is provided by the species-specific defensive reaction (SSDR) theory, which postulates that the same innately determined defensive behaviors (like freezing and flight) are triggered by all perceived environmental threats-from natural predators to electric foot shocks in a laboratory protocol (1). This seemingly limited response repertoire suggested the plausible hypothesis that an animal's defensive behavior system processes cues about predators and an artificial threat in the same way and has led to a unitary view of the neural network mediating fear responses, with the central amygdalar nucleus playing a critical role in linking fear processing and defensive responses (2). However, it is also possible that differentiable mechanisms are engaged. Animals are naturally selected to protect themselves from dangers associated with the presence of a predator or a dominant conspecific, which evokes the sensation of fear and associated behavioral responses (3), whereas it is reasonable to postulate that, in contrast, physically harmful stimuli alone may evoke pain with or without fear.Fear responses to predators or dominant conspecifics are comparable to other forms of goal-oriented behavior like feeding, drinking, and mating in the sense that they appear to be accompanied by strong motivation or drive followed by behaviors critical for maint...

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Section: Discussionmentioning

confidence: 80%

Dissecting the brain's fear system reveals the hypothalamus is critical for responding in subordinate conspecific intruders

Motta¹,

Goto²,

Gouveia³

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

176

206

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“…expression in DOM and SUB males above an initial response to handling. The MeA has been implicated in a variety of behavioral responses [e.g., mating (Lehman et al, 1980;Lehman and Winans, 1982;Kollack-Walker and Newman, 1995), aggression (Shibata et al, 1982;L uiten et al, 1985;Kollack-Walker and Newman, 1995;Potegal et al, 1996b), and affiliative behavior (Kirkpatrick et al, 1994)], and induction of c-fos mRNA after fighting is consistent with a role of this brain region in behavioral arousal (De Jonge et al, 1992;Kollack-Walker and Newman, 1995;Potegal et al, 1996b) and social memory (Bolhuis et al, 1984;Vochteloo and Koolhaas, 1987). The SON showed the greatest increase in DOM males.…”

Section: Acute Exposure To Intermale Aggressionmentioning

confidence: 87%

Social Stress in Hamsters: Defeat Activates Specific Neurocircuits within the Brain

1997

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During an agonistic encounter, subordinate male hamsters display defensive and submissive postures and show increased secretion of glucocorticoids, whereas dominant males do not. To determine whether specific neuronal pathways are activated during the behavioral and neuroendocrine responses of subordinate males, expression of c-fos mRNA within the brains of subordinate males was compared with the pattern in dominant males after fighting. After 1 week of handling, pairs of hamsters were either swapped between cages (handled control males), or were allowed to interact for 30 min [dominant (DOM) males and subordinate (SUB) males]. A second group of control animals that received no handling or social stimulation (unhandled control males) were also included. After testing, all animals were killed by decapitation, their brains were removed for c-fos in situ hybridization, and trunk blood was collected for analysis of plasma cortisol and corticosterone levels. Exposure of males to their partner's cage for 30 min resulted in increased expression of c-fos mRNA in multiple brain regions. In addition, fighting increased c-fos expression in the medial amygdaloid nucleus of both DOM and SUB males as well as having more selective effects. In DOM males, c-fos expression was elevated within the supraoptic nucleus of the hypothalamus. In SUB males, c-fos expression increased within a multitude of brain areas, including cingulate cortex, lateral septum, bed nucleus of the stria terminalis, medial preoptic area, several hypothalamic nuclei, central amygdaloid nucleus, amygdalohippocampal area, dorsal periaqueductal gray, dorsal raphe, cuneiform nucleus, and locus coeruleus. These findings are discussed in relation to neurocircuits associated with behavioral arousal and stress.

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“…Although the type II glucocorticoid receptor agonist dexamethasone has been shown to suppress AVP mRNA levels in AME, gonadal steroids seem to be more important in the regulation of AVP in this region, because the decrease is contingent on a concomitant suppression of testosterone levels (Urban et al, 1991). Testosterone has also be shown to play a key role in the regulation of extrahypothalamic AVP expression in other models, because castration leads to a decrease in AVP mRNA and immunoreactivity, an effect that can be reversed by testoster- Behaviors mediated by the vasopressinergic circuit arising from the AME include aggression (Koolhaas et al, 1990;Compaan et al, 1993), copulation (Smock et al, 1992), and social recognition (Lehman et al, 1980;Bolhuis et al, 1984;Bluthe et al, 1990). The decreased AVP expression in the AME may play a role in the reduction of aggressive and sexual behaviors in the subordinate animals after the stress-induced decline in testosterone secretion.…”

Section: Discussionmentioning

confidence: 99%

Chronic Social Stress Alters Levels of Corticotropin-Releasing Factor and Arginine Vasopressin mRNA in Rat Brain

et al. 1997

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In the visible burrow system model of chronic social stress, male rats housed in mixed-sex groups quickly form a dominance hierarchy in which the subordinates appear to be severely stressed. A subgroup of subordinates have an impaired corticosterone response after presentation of a novel restraint stressor, leading to their designation as nonresponsive subordinates. To examine the mechanism underlying the blunted corticosterone response in these animals, in situ hybridization histochemistry was used to quantify corticotropin-releasing factor (CRF) and arginine vasopressin (AVP) mRNA expression in the brain. In two separate visible burrow system experiments, the nonresponsive subordinates expressed a significantly lower average number of CRF mRNA grains per cell in the paraventricular hypothalamic nucleus compared with stress-responsive subordinates, dominants (DOM), or cage-housed control (CON) rats. The number of CRF mRNA labeled cells was also significantly lower in nonresponders than in responsive subordinates or DOM. In the central amygdala, CRF mRNA levels were increased in both groups of subordinates compared with CON rats, whereas responsive subordinates exhibited higher levels than the DOM rats as well. AVP mRNA levels did not vary with behavioral rank in any subdivision of the paraventricular hypothalamic nucleus. In the medial amygdala, the number of cells expressing AVP mRNA was significantly greater in CON rats compared with both groups of subordinates, although the average number of AVP mRNA grains per cell did not vary with rank. In addition, the number of AVP-positive cells significantly correlated with plasma testosterone level.

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The corticomedial amygdala and learning in an agonistic situation in the rat

Cited by 52 publications

References 24 publications

Dissecting the brain's fear system reveals the hypothalamus is critical for responding in subordinate conspecific intruders

Dissecting the brain's fear system reveals the hypothalamus is critical for responding in subordinate conspecific intruders

Social Stress in Hamsters: Defeat Activates Specific Neurocircuits within the Brain

Chronic Social Stress Alters Levels of Corticotropin-Releasing Factor and Arginine Vasopressin mRNA in Rat Brain

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