Distinct regions of periaqueductal gray (PAG) are involved in freezing behavior in hooded PVG rats on the cat-freezing test apparatus

Farook, Justin M.; Wang, Qian; Moochhala, Shabbir; Zhu, Yi‐Zhun; Lee, L.; Wong, Peter T.-H.

doi:10.1016/j.neulet.2003.10.011

Cited by 23 publications

(13 citation statements)

References 21 publications

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“…3). Similarly, infralimbic cortex' total effects on vlPAG, another brain area thought to be involved in creating the behavioral freezing response (Vianna et al, 2001a, Farook et al, 2004, De Luca-Vinhas et al, 2006, were found to be negative in the extinction group, and added up to near zero in the renewal group. Total effects from MGD, LA and CEAm on vlPAG showed a reversal of sign, indicating that increase in activity in those three areas in the extinction group may lead to a proportional decrease in activity in the vlPAG, while an increase in those three areas in the renewal group may lead to an increase in the vlPAG's activity in the renewal group.…”

Section: Discussionmentioning

confidence: 96%

Network model of fear extinction and renewal functional pathways

2007

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The objective of this study was to examine the opposite behavior responses of conditioned fear extinction and renewal and how they are represented by network interactions between brain regions. This work is a continuation of a series of brain mapping studies of various inhibitory phenomena, including conditioned inhibition, blocking and extinction. A tone-footshock fear conditioning paradigm in rats was used, followed by extinction and testing in two different contexts. Fluorodeoxyglucose autoradiography was used to compare mean regional brain activity and interregional correlations resulting from the presentation of the extinguished tone in or out of the extinction context. A confirmatory structural equation model, constructed from a neural network proposed to underlie fear extinction, showed a reversal from negative regional interactions during extinction recall to positive interactions during fear renewal. Additionally, the magnitude of direct effects was different between groups, reflecting a change in the strength of the influences conveyed through those pathways. The results suggest that the extinguished tone encountered outside of the extinction context recruits auditory and limbic areas, which in turn influence the interactions of the infralimbic cortex with the amygdala and ventrolateral periaqueductal gray. Interestingly, the results also suggest that two independent pathways influence conditioned freezing: one from the central amygdaloid nucleus and the other from the infralimbic cortex directly to the ventrolateral periaqueductal gray. KeywordsPath analysis; Structural equation modeling; Brain mapping; Prefrontal cortex; Hippocampus; AmygdalaIn the past few years, there has been increased interest in the neural substrates of fear extinction, partly due to the relevance of fear extinction to the treatment of anxiety disorders (Craske, 1999). Brain lesion, stimulation, recording and metabolic mapping studies have addressed the question of which brain areas are important in fear extinction learning and memory in both animals and humans (Quirk et al.,

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Section: Discussionmentioning

confidence: 96%

Network model of fear extinction and renewal functional pathways

2007

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“…Lesions of the medial amygdala, basolateral amygdala, PMd, and ventral hippocampus decreased freezing behavior in rats exposed to cat odor (Blanchard et al, 2005; Blanchard et al, 2003; Li et al, 2004, Pentkowski et al, 2006, Takahashi et al, 2007, Takahashi et al, 2005, Vazdarjanova et al, 2001). Lesions of the PMd, hippocampus, medial amygdala, and ventrolateral PAG also decreased defensive behavior in response to a live cat exposure (Blanchard et al, 1972, Blanchard et al, 2005, Blanchard et al, 2003, Canteras et al, 1997, Cezario et al, 2008, Farook et al, 2003). Temporary inactivation of the BNST, medial and basolateral amygdala have been shown to decrease freezing to TMT, a predator odor that is a component of fox feces (Fendt et al, 2003, Fendt et al, 2005, Muller et al, 2006).…”

Section: Introductionmentioning

confidence: 90%

Disruption of neuroendocrine stress responses to acute ferret odor by medial, but not central amygdala lesions in rats

Masini¹,

Sasse²,

Garcia³

et al. 2009

Brain Research

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Investigations of the neural pathways associated with responses to predators have implicated the medial amygdala (MeA) as an important region involved in defensive behaviors. To our knowledge, however, the involvement of the MeA in neuroendocrine responses to predator odor exposure has not been investigated. Therefore, the present study examined the effects of MeA disruption in rats exposed to ferret or control odor on hypothalamo-pituitary-adrenocortical (HPA) axis activation. Bilateral lesions of the MeA were made in Sprague-Dawley rats with the neurotoxin ibotenic acid (10 µg/µl; 0.3 µl /side). As a control for regional specificity, additional groups of rats were given lesions in the central amygdala (CeA). One week after recovery, the rats were exposed to ferret or strawberry control towels in small cages to examine HPA axis responses as determined by plasma corticosterone and adrenocorticotropin hormone (ACTH) levels. Rats with complete bilateral MeA but not CeA lesions displayed significantly less corticosterone and ACTH release compared to shamoperated control rats only in the ferret odor conditions. These results suggest that the MeA is an important structure involved in the HPA axis responses to predator odors, in support of previous studies investigating behavioral responses under similar conditions.

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“…The dorsolateral column produces escape behaviors including jumping and running, and the ventrolateral column freezing behavior (Bandler et al, 2000; Brandao et al, 2008). Lesion of the ventrolateral periaqueductal gray reduced freezing in adult rats exposed to a cat (De Oca et al, 1998; Farook et al, 2004). The periaqueductal gray appears to have a similar function in young animals.…”

Section: Neural Processes Underlying the Developmental Changes In mentioning

confidence: 99%

Plasticity of defensive behavior and fear in early development

Wiedenmayer

2009

Neuroscience & Biobehavioral Reviews

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Animals have the ability to respond to threatening situations with sets of defensive behaviors. This review demonstrates that defensive behaviors change during early life in mammals. First, unlearned responses are reorganized during early ontogeny and expressed in an age-specific way. Second, the expression of defensive responses is influenced by early experience prior to the first encounter with a threat. Third, once animals have been exposed to a threatening stimulus they subsequently modify their behavior. The neural bases of defensive behavior and the processes that alter them during development are discussed. Maturation of components and connections of the fear circuit seem to contribute to changes in unlearned fear responses. Early experience and learning modify these developmental processes and shape the expression of defensive behavior. Continuous reorganization of the neural substrate and defensive behavior during ontogeny seems to allow the animal to adjust to the conditions it encounters at a given age in a given environment. It is proposed that the developmental changes in defensive behavior can be conceptualized as phenotypic plasticity.

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Distinct regions of periaqueductal gray (PAG) are involved in freezing behavior in hooded PVG rats on the cat-freezing test apparatus

Cited by 23 publications

References 21 publications

Network model of fear extinction and renewal functional pathways

Network model of fear extinction and renewal functional pathways

Disruption of neuroendocrine stress responses to acute ferret odor by medial, but not central amygdala lesions in rats

Plasticity of defensive behavior and fear in early development

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