Innate and conditioned reactions to threat in rats with amygdaloid lesions.

Blanchard, D. Caroline; Blanchard, Robert J.

doi:10.1037/h0033521

Cited by 691 publications

(366 citation statements)

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“…Since the amygdala mediates adaptive and maladaptive fear and anxiety responses (Blanchard and Blanchard, 1972;LeDoux, 2000;Davis and Whalen, 2001;Amaral, 2003;Kalin et al, 2004), it is of particular importance that ferret exposure increased c-fos expression within various nuclei of the amygdala. Consistent with previous studies using cat odor as a stimulus (Dielenberg et al, 2001;McGregor et al, 2004) we found that 10 min of ferret exposure resulted in a robust increase in the number of Fos-positive cells within the MeA.…”

Section: Discussionmentioning

confidence: 99%

“…Considerable evidence implicates the amygdala in conditioned and unconditioned fear responses (Blanchard and Blanchard, 1972;LeDoux, 2000;Davis and Whalen, 2001;Amaral, 2003;Kalin et al, 2004), and human functional imaging studies have demonstrated increased amygdala activation in some patients with anxiety and depressive disorders (Drevets, 2003;Rauch et al, 2003). Furthermore, evidence supports a role for the amygdala CRF system in mediating anxiety and fear.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

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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“…A central role of amygdalar neurons is indicated by findings that amygdala lesions impair the acquisition of conditioned immobility (LeDoux et al, 1988; Fanselow and K im, 1994;LeDoux, 1995), autonomic responding (Blanchard and Blanchard, 1972;Spevack et al, 1975;Kapp et al, 1979;Gentile et al, 1986;Iwata et al, 1986;Helmstetter, 1992) and fear-potentiated startle behavior (Davis, 1986(Davis, , 1992Hitchcock and Davis, 1987;Sananes and Davis, 1992). Also, amygdalar neurons exhibit associative, training-induced activity (TIA) during Pavlovian conditioning (Umemoto and Olds, 1975;Applegate et al, 1982;Pascoe and Kapp, 1985;Nishijo et al, 1988; Muramoto et al, 1993;McEchron et al, 1995;Quirk et al, 1995).…”

Section: Abstract: Limbic Thalamus; Cingulate Cortex; Amygdala; Learmentioning

confidence: 99%

Medial Geniculate Lesions Block Amygdalar and Cingulothalamic Learning-Related Neuronal Activity

Poremba

Gabriel

1997

J. Neurosci.

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This study assessed the role of the thalamic medial geniculate (MG) nucleus in discriminative avoidance learning, wherein rabbits acquire a locomotory response to a tone [conditioned stimulus (CS)ϩ] to avoid a foot shock, and they learn to ignore a different tone (CSϪ) not predictive of foot shock. Limbic (anterior and medial dorsal) thalamic, cingulate cortical, or amygdalar lesions severely impair acquisition, and neurons in these areas develop training-induced activity (TIA): more firing to the CSϩ than to the CSϪ. MG neurons exhibit TIA during learning and project to the amygdala. The MG neurons may supply afferents essential for amygdalar and cingulothalamic TIA and for avoidance learning. To test this hypothesis, bilateral electrolytic or excitotoxic ibotenic acid MG nuclear lesions were induced, and multiunit recording electrodes were chronically implanted into the anterior and posterior cingulate cortex, the anterior-ventral and medial-dorsal thalamic nuclei, and the basolateral nucleus of the amygdala before training. Learning was severely impaired and TIA was abolished in all areas in rabbits with lesions. Thus learning and TIA require the integrity of the MG nucleus. Only damage in the medial MG division was significantly correlated with the learning deficit. The lesions abolished the sensory response of amygdalar neurons, and they attenuated (but did not eliminate) the sensory response of cingulothalamic neurons, suggesting the existence of extra geniculate sources of auditory transmission to the cingulothalamic areas. Key words: limbic thalamus; cingulate cortex; amygdala; learning; instrumental conditioning; anterior ventral nucleus; medial dorsal nucleusThere is currently a great interest in the neural circuitry underlying aversively motivated learning (for review, see Davis, 1992;Gabriel, 1993;Lennartz and Weinberger, 1994;LeDoux, 1995;McGaugh et al., 1995;. A central role of amygdalar neurons is indicated by findings that amygdala lesions impair the acquisition of conditioned immobility (LeDoux et al., 1988; Fanselow and K im, 1994;LeDoux, 1995), autonomic responding (Blanchard and Blanchard, 1972;Spevack et al., 1975;Kapp et al., 1979;Gentile et al., 1986;Iwata et al., 1986;Helmstetter, 1992) and fear-potentiated startle behavior (Davis, 1986(Davis, , 1992Hitchcock and Davis, 1987;Sananes and Davis, 1992). Also, amygdalar neurons exhibit associative, training-induced activity (TIA) during Pavlovian conditioning (Umemoto and Olds, 1975;Applegate et al., 1982;Pascoe and Kapp, 1985;Nishijo et al., 1988; Muramoto et al., 1993;McEchron et al., 1995;Quirk et al., 1995).An involvement of the medial geniculate (MG) nucleus in aversively motivated learning is indicated by the observation of TIA in the medial division of the MG nucleus (MGm) (Olds et al., 1972;Gabriel et al., 1975;Gabriel et al., 1976;Ryugo and Weinberger, 1978;Birt and Olds, 1981;Weinberger, 1982;Edeline, 1990;Edeline and Weinberger, 1992;McEchron et al., 1995), and by impaired conditioning in animals with MG lesions (Iwata et al., 198...

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“…Context representations play a critical role in learning and memory because they provide a cue that primes the context-appropriate memories and behaviors (Blanchard and Blanchard, 1972;Godden and Baddely, 1975;Balaz et al, 1980;Fanselow, 1986). When a subject encounters a known context, the hippocampal context code is expressed and the appropriate memories and behaviors are primed.…”

Section: What Constitutes a Context?mentioning

confidence: 99%

Hippocampal place cells, context, and episodic memory

2006

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ABSTRACT:Although most observers agree that the hippocampus has a critical role in learning and memory, there remains considerable debate about the precise functional contribution of the hippocampus to these processes. Two of the most influential accounts hold that the primary function of the hippocampus is to generate cognitive maps and to mediate episodic memory processes. The well-documented spatial firing patterns (place fields) of hippocampal neurons in rodents, along with the spatial learning impairments observed with hippocampal damage support the cognitive mapping hypothesis. The amnesia for personally experienced events seen in humans with hippocampal damage and the data of animal models, which show severe memory deficits associated with hippocampal lesions, support the episodic memory account. Although an extensive literature supports each of these hypotheses, a specific contribution of place cells to episodic memory has not been clearly demonstrated. Recent data from our laboratory, together with previous findings, indicate that hippocampal place fields and neuronal responses to task-relevant stimuli are highly sensitive to the context, even when the contexts are defined by abstract task demands rather than the spatial geometry of the environment. On the basis of these findings, it is proposed that place fields reflect a more general context processing function of the hippocampus. Hippocampal context representations could serve to differentiate contexts and prime the relevant memories and behaviors. Since episodic memories, by definition, include information about the time and place where the episode occurred, contextual information is a necessary prerequisite for any episodic memory. Thus, place fields contribute importantly to episodic memory as part of the needed context representations. Additionally, recent findings indicate that hippocampal neurons differentiate contexts at progressively finer levels of detail, suggesting a hierarchical coding scheme which, if combined with temporal information, could provide a means of differentiating memory episodes. V V C 2006 Wiley-Liss, Inc.

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Innate and conditioned reactions to threat in rats with amygdaloid lesions.

Cited by 691 publications

References 10 publications

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

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

Medial Geniculate Lesions Block Amygdalar and Cingulothalamic Learning-Related Neuronal Activity

Hippocampal place cells, context, and episodic memory

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