Conditioned stimulus determinants of conditioned response form in Pavlovian fear conditioning.

Kim, Stephen D.; Rivers, Steven P.; Bevins, Rick A.; Ayres, John J. B.

doi:10.1037/0097-7403.22.1.87

Cited by 25 publications

(20 citation statements)

References 18 publications

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“…Although higher baseline freezing levels were seen after conditioning with light cues as expected [28,29], mice lacking adult neurogenesis froze less than wild types in the ambiguous fear condition but not in the reliable fear condition (S3 Fig). Unconditioned responses to initial presentations of tone, light, and shock were similar in both genotypes, indicating normal sensitivity to the cue and shock in mice lacking adult neurogenesis (S4A–S4D Fig).…”

Section: Resultssupporting

confidence: 66%

Ongoing neurogenesis in the adult dentate gyrus mediates behavioral responses to ambiguous threat cues

et al. 2017

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Fear learning is highly adaptive if utilized in appropriate situations but can lead to generalized anxiety if applied too widely. A role of predictive cues in inhibiting fear generalization has been suggested by stress and fear learning studies, but the effects of partially predictive cues (ambiguous cues) and the neuronal populations responsible for linking the predictive ability of cues and generalization of fear responses are unknown. Here, we show that inhibition of adult neurogenesis in the mouse dentate gyrus decreases hippocampal network activation and reduces defensive behavior to ambiguous threat cues but has neither of these effects if the same negative experience is reliably predicted. Additionally, we find that this ambiguity related to negative events determines their effect on fear generalization, that is, how the events affect future behavior under novel conditions. Both new neurons and glucocorticoid hormones are required for the enhancement of fear generalization following an unpredictably cued threat. Thus, adult neurogenesis plays a central role in the adaptive changes resulting from experience involving unpredictable or ambiguous threat cues, optimizing behavior in novel and uncertain situations.

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Section: Resultssupporting

confidence: 66%

Ongoing neurogenesis in the adult dentate gyrus mediates behavioral responses to ambiguous threat cues

et al. 2017

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“…Thus, distinct processes must mediate the conditioned responses of freezing and suppression. This conclusion is also supported by behavioral evidence demonstrating that visual CSs, which elicit less freezing than auditory CSs, cause more suppression that auditory CSs (Kim et al 1996). This does not imply that suppression is a poor index of fear, rather, it suggests that suppression may be a distinct conditioned response to fear-eliciting stimuli.…”

Section: Pag Lesions and Suppressionsupporting

confidence: 70%

Lesions of Periaqueductal Gray Dissociate-Conditioned Freezing From Conditioned Suppression Behavior in Rats

Amorapanth

Nader

LeDoux³

1999

Learn. Mem.

102

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It is commonly assumed that suppression of an ongoing behavior is an indirect measure of freezing behavior. We tested whether conditioned suppression and freezing are the same or distinct conditioned responses. Rats were trained to press a bar for food and then given fear-conditioning sessions in which a tone was paired with a foot shock (two pairings a day for 2 days). They then received either sham or electrolytic lesions of the periaqueductal gray (PAG). Post-training PAG lesions blocked freezing to the conditioned stimulus (CS), but had no effect on the suppression of operant behavior to the same CS. Thus, conditioned suppression and freezing, which both cause a cessation in activity, appear to be mediated by separate processes.

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“…The observed absence of freezing to the light distractor cannot be explained by the poor associability of the light to the shock. Previous studies have shown that light can serve as a CS in fear conditioning experiments (32). In a separate study involving 24 animals, we confirmed that the flashing light stimulus (in the absence of a tone) was able to acquire CS properties, in a delay fear conditioning procedure (percent time spent freezing to light Ϯ SEM: Delay conditioning, 64 Ϯ 8.76%; Shock-only, 4.89 Ϯ 2.95%, P Ͻ 0.05).…”

Section: Resultsmentioning

confidence: 99%

Trace but not delay fear conditioning requires attention and the anterior cingulate cortex

Han

O’Tuathaigh

Trigt

et al. 2003

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

273

228

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Higher cognitive functions such as attention have been difficult to model in genetically tractable organisms. In humans, attentiondistracting stimuli interfere with trace but not delay conditioning, two forms of associative learning. Attention has also been correlated with activation of anterior cingulate cortex (ACC), but its functional significance is unclear. Here we show that a visual distractor interferes selectively with trace but not delay auditory fear conditioning in mice. Trace conditioning is associated with increased neuronal activity in ACC, as assayed by relative levels of c-fos expression, and is selectively impaired by lesions of this structure. The effects of the ACC lesions are unlikely to be caused by indirect impairment of the hippocampus, which is required for mnemonic aspects of trace conditioning. These data suggest that trace conditioning may be useful for studying neural substrates of attention in mice, and implicate the ACC as one such substrate. Selective attention is thought to contribute to conscious awareness, but its neural basis is poorly understood. The search for the neural substrates of attention has been concentrated in the primate visual system (1, 2). Although extremely useful for identifying neural correlates of attention, primates offer limited accessibility for functional perturbation experiments, prompting a search for alternative animal models more amenable to tests of causation. Although some attentional models have been established in rats (3), they depend on operant conditioning paradigms that have proven difficult to extend to mice, and require lengthy training periods.Studies in humans have suggested that attention is required for certain forms of associative learning (4). Associative learning paradigms, such as fear conditioning, have been successfully extended from rats to mice (5). Two commonly used variants of this procedure are delay and trace conditioning. In delay fear conditioning, a conditioned stimulus (CS), such as a tone, is immediately followed by an unconditioned stimulus (US), such as a foot shock. In trace conditioning, a time gap is introduced between the end of the CS and the start of the US. In human eye blink conditioning, another associative learning paradigm, distracting stimuli interfere with trace but not delay conditioning, suggesting that attention is necessary for the former type of learning (4, 6-10). More recent studies have suggested a similar requirement for attention in trace but not delay fear conditioning in humans (11).Potential neural substrates of attention have been identified by functional imaging in humans. For example, attention has been correlated with increased activity in the anterior cingulate cortex (ACC) (12-17). Furthermore, the ACC is preferentially activated during presentation of the conditional stimulus, compared with that of a meaningless stimulus, during aversive trace conditioning (18). The ACC has also been implicated in tasks requiring visual attention in rats (3,(19)(20)(21)(22)(23). Lesion studies have show...

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Conditioned stimulus determinants of conditioned response form in Pavlovian fear conditioning.

Cited by 25 publications

References 18 publications

Ongoing neurogenesis in the adult dentate gyrus mediates behavioral responses to ambiguous threat cues

Ongoing neurogenesis in the adult dentate gyrus mediates behavioral responses to ambiguous threat cues

Lesions of Periaqueductal Gray Dissociate-Conditioned Freezing From Conditioned Suppression Behavior in Rats

Trace but not delay fear conditioning requires attention and the anterior cingulate cortex

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