Lesions of structures showing FOS expression to cat presentation: Effects on responsivity to a Cat, Cat odor, and nonpredator threat

Blanchard, D. Caroline; Canteras, Newton S.; Markham, Chris; Pentkowski, Nathan S.; Blanchard, Robert J.

doi:10.1016/j.neubiorev.2005.04.019

Cited by 166 publications

(123 citation statements)

References 17 publications

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“…Finally, present results suggest that CRF systems may be functionally involved in unconditioned defenses, acting in some of the same brain sites that have previously been investigated as components of an antipredator defense system [14]. An overhead view of the MDTB apparatus.…”

Section: Discussionsupporting

confidence: 53%

Effects of intra-PAG infusion of ovine CRF on defensive behaviors in Swiss-Webster mice

Carvalho-Netto

Litvin

Nunes-de-Souza

et al. 2007

Behavioural Brain Research

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The midbrain dorsal periaqueductal grey (DPAG) is part of the brain defensive system involved in active defense reactions to threatening stimuli. Corticotrophin releasing factor (CRF) is a peptidergic neurotransmitter that has been strongly implicated in the control of both behavioral and endocrine responses to threat and stress. We investigated the effect of the nonspecific CRF receptor agonist, ovine CRF (oCRF), injected into the DPAG of mice, in two predator-stress situations, the Mouse Defense Test Battery (MDTB), and the Rat Exposure Test (RET). In the MDTB, oCRF weakly modified defensive behaviors in mice confronted by the predator (rat); e.g. it increased avoidance distance when the rat was approached and escape attempts (jump escapes) in forced contact. In the RET, drug infusion enhanced duration in the chamber while reduced tunnel and surface time, and reduced contact with the screen which divides the subject and the predator. oCRF also reduced both frequency and duration of risk assessment (stretch attend posture: SAP) in the tunnel and tended to increase freezing. These findings suggest that patterns of defensiveness in response to low intensity threat (RET) are more sensitive to intra-DPAG oCRF than those triggered by high intensity threats (MDTB). Our data indicate that CRF systems may be functionally involved in unconditioned defenses to a predator, consonant with a role for DPAG CRF systems in the regulation of emotionality.

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Section: Discussionsupporting

confidence: 53%

Effects of intra-PAG infusion of ovine CRF on defensive behaviors in Swiss-Webster mice

Carvalho-Netto

Litvin

Nunes-de-Souza

et al. 2007

Behavioural Brain Research

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“…These linkages with the hypothalamus are consistent with the MeA being the amygdala region that has the greatest modulatory influence on stress-induced HPA activity. Furthermore, recent studies have associated the MeA with fear and anxiety responses induced by the odor of predators (Blanchard et al, 2005;Takahashi et al, 2005;Muller and Fendt, 2006). For example, excitotoxic lesions or inactivation of the MeA blocks freezing behavior in rats exposed to odors associated with a cat or fox (Li et al, 2004;Blanchard et al, 2005).…”

Section: Discussionmentioning

confidence: 99%

Predator threat induces behavioral inhibition, pituitary-adrenal activation and changes in amygdala CRF-binding protein gene expression

Roseboom

Nanda

Bakshi

et al. 2007

Psychoneuroendocrinology

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SummaryBehavioral inhibition (BI) is an adaptive defensive response to threat; however, extreme BI is associated with anxiety-related psychopathology. When rats are exposed to a natural predator they display stress-and anxiety-related behavioral alterations and physiological activation. To develop a preclinical rodent model to study mechanisms underlying human BI and anxiety, we examined the extent to which ferret exposure elicits anxiety-related BI and HPA and amygdala activation of the CRF system. In the first experiment, BI and other behaviors were assessed in the presence or absence of a ferret. In the second experiment, ferret-induced corticosterone release and changes in brain cfos expression were assessed. In the final experiment, gene chip and quantitative real time-PCR analyses were performed on amygdala tissue from control and ferret-exposed rats. Ferret exposure increased BI and submissive posturing, as well as plasma corticosterone and the number of Fospositive cells in several brain regions including the amygdala. Gene expression analysis revealed increased amygdalar mRNA for CRF-binding protein, but not the CRF 1 receptor, CRF 2 receptor or CRF. In rodents, ferret exposure can be used to elicit anxiety-related BI, which is associated with HPA and amygdala activation. Since the amygdala and the CRF system have been implicated in adaptive and maladaptive anxiety responses in humans, these data support use of our rodent model to further investigate mechanisms underlying anxiety-related psychopathology in humans.

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“…Several studies have investigated the innate fear of laboratory rodents toward cat odors (7)(8)(9)(10)(11). These studies have delineated a neuroanatomical circuit comprising the medial hypothalamic zone and associated forebrain structures.…”

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confidence: 99%

Behavioral changes induced by Toxoplasma infection of rodents are highly specific to aversion of cat odors

Vyas

Kim²,

Giacomini

et al. 2007

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

517

546

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The protozoan parasite Toxoplasma gondii blocks the innate aversion of rats for cat urine, instead producing an attraction to the pheromone; this may increase the likelihood of a cat predating a rat. This is thought to reflect adaptive, behavioral manipulation by Toxoplasma in that the parasite, although capable of infecting rats, reproduces sexually only in the gut of the cat. The ''behavioral manipulation'' hypothesis postulates that a parasite will specifically manipulate host behaviors essential for enhancing its own transmission. However, the neural circuits implicated in innate fear, anxiety, and learned fear all overlap considerably, raising the possibility that Toxoplasma may disrupt all of these nonspecifically. We investigated these conflicting predictions. In mice and rats, latent Toxoplasma infection converted the aversion to feline odors into attraction. Such loss of fear is remarkably specific, because infection did not diminish learned fear, anxiety-like behavior, olfaction, or nonaversive learning. These effects are associated with a tendency for parasite cysts to be more abundant in amygdalar structures than those found in other regions of the brain. By closely examining other types of behavioral patterns that were predicted to be altered we show that the behavioral effect of chronic Toxoplasma infection is highly specific. Overall, this study provides a strong argument in support of the behavioral manipulation hypothesis. Proximate mechanisms of such behavioral manipulations remain unknown, although a subtle tropism on part of the parasite remains a potent possibility.behavioral manipulation ͉ fear ͉ parasites ͉ predator T he ''behavioral manipulation'' hypothesis states that a parasite can alter host behavior specifically to increase its own transmission efficiency (1, 2). After an acute infection, the protozoan parasite Toxoplasma gondii latently persists in the brain for the life of an infected host, offering an opportunity to study the behavioral manipulation hypothesis (3). Toxoplasma reproduces sexually in a two-species life cycle (4). The sexual phase of its reproduction occurs in the feline intestine, from which highly stable oocysts are excreted in the feces. Grazing animals, including rodents, can then ingest these oocysts. In these hosts, Toxoplasma forms cysts and persists in the central nervous system. The life cycle is completed when a cat eats an infected animal. Recent reports indicate that the parasite blunts the innate aversion of rats for the urine of cats, converting this aversion to an attraction (5), although it does not interfere with energetically costly behaviors related to mating success and social status (6). These findings agree with the behavioral manipulation hypothesis, which predicts that parasites will alter only behaviors that are beneficial to their transmission while leaving other behaviors intact.Several studies have investigated the innate fear of laboratory rodents toward cat odors (7-11). These studies have delineated a neuroanatomical circuit comprising ...

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Lesions of structures showing FOS expression to cat presentation: Effects on responsivity to a Cat, Cat odor, and nonpredator threat

Cited by 166 publications

References 17 publications

Effects of intra-PAG infusion of ovine CRF on defensive behaviors in Swiss-Webster mice

Effects of intra-PAG infusion of ovine CRF on defensive behaviors in Swiss-Webster mice

Predator threat induces behavioral inhibition, pituitary-adrenal activation and changes in amygdala CRF-binding protein gene expression

Behavioral changes induced by Toxoplasma infection of rodents are highly specific to aversion of cat odors

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