Adaptations or pathologies? Long-term changes in brain and behavior after a single exposure to severe threat

Wiedenmayer, Christoph P.

doi:10.1016/j.neubiorev.2003.09.005

Cited by 51 publications

(38 citation statements)

References 104 publications

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“…So far, however, long-lasting consequences of aversive encounters like sensitization have been described for severe stressors only, including social defeat or footshocks of high intensity or frequency (for review, see Stam et al 2000;Korte and de Boer 2003;Wiedenmayer 2004). Footshocks of intermediate intensity, in contrast, caused only transient changes in fear-related behavior that were confined to a relatively narrow time window after the aversive incident (Boulis and Davis 1989;Davis 1989;Korte and de Boer 2003).…”

Section: Learning and Memory 779mentioning

confidence: 99%

“…With one to three pairings of a tone with a footshock of intermediate intensity, conventional conditioning protocols for mice appear far less aversive than those reported for sensitization or other nonassociative changes in behavioral performance (for reviews, see Korte and de Boer 2003;Wiedenmayer 2004). Therefore, the present study sought to investigate the impact of sensitization and habituation on expression and extinction of conditioned fear exemplarily in C57BL/6JOlaHsd mice.…”

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confidence: 98%

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Nonassociative learning processes determine expression and extinction of conditioned fear in mice

Kamprath¹,

Wotjak²

2004

Learn. Mem.

169

151

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Freezing to a tone following auditory fear conditioning is commonly considered as a measure of the strength of the tone-shock association. The decrease in freezing on repeated nonreinforced tone presentation following conditioning, in turn, is attributed to the formation of an inhibitory association between tone and shock that leads to a suppression of the expression of fear. This study challenges these concepts for auditory fear conditioning in mice. We show that acquisition of conditioned fear by a few tone-shock pairings is accompanied by a nonassociative sensitization process. As a consequence, the freezing response of conditioned mice seems to be determined by both associative and nonassociative memory components. Our data suggest that the intensity of freezing as a function of footshock intensity is primarily determined by the nonassociative component, whereas the associative component is more or less categorical. We next demonstrate that the decrease in freezing on repeated nonreinforced tone presentation following conditioning shows fundamental properties of habituation. Thus, it might be regarded as a habituation-like process, which abolishes the influence of sensitization on the freezing response to the tone without affecting the expression of the associative memory component. Taken together, this study merges the dual-process theory of habituation with the concept of classical fear conditioning and demonstrates that sensitization and habituation as two nonassociative learning processes may critically determine the expression of conditioned fear in mice.

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Section: Learning and Memory 779mentioning

confidence: 99%

mentioning

confidence: 98%

Nonassociative learning processes determine expression and extinction of conditioned fear in mice

Kamprath¹,

Wotjak²

2004

Learn. Mem.

169

151

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“…Increasing evidence also points out that inappropriate stress responses and/or control might be associated with the development of physiological alterations and neuropsychiatric disorders (de Kloet, Joels, & Holsboer, 2005;Heim & Nemeroff, 1999;Mazure, Kincare, & Schaffer, 1995;McEwen, 2005;Sandi & Bisaz, 2007;Wiedenmayer, 2004).…”

Section: Introductionmentioning

confidence: 99%

Learning under stress: A role for the neural cell adhesion molecule NCAM

Bisaz

Conboy

Sandi

2009

Neurobiology of Learning and Memory

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a b s t r a c tStress is known to be a potent modulator of brain function and cognition. While prolonged and/or excessive stress generally exerts negative effects on learning and memory processes, acute stress can have differential effects on memory function depending on a number of factors (such as stress duration, stress intensity, timing and the source of the stress, as well as the learning type under study). Here, we have focused on the effects of 'acute' stress, and examined the literature attending to whether the ''source of stress" is 'intrinsic' (i.e., when stress is originated by the cognitive task) or 'extrinsic' (i.e., when stress is induced by elements not related to the cognitive task). We have questioned here whether the neural cell adhesion molecule of the immunoglobulin superfamily (NCAM) contributes to the neurobiological mechanisms that translate the effects of these two different stress sources into the different behavioral and cognitive outcomes. NCAM is a cell adhesion macromolecule known to play a critical role in development and plasticity of the nervous system. NCAM and its post-translational modified form PSA-NCAM are critically involved in mechanisms of learning and memory and their expression levels are known to be highly susceptible to modulation by stress. Whereas available data are insufficient to conclude as to whether NCAM mediates extrinsic stress effects on learning and memory processes, we present systematic evidence supporting a key mediating role for both NCAM and PSA-NCAM in the facilitation of memory consolidation induced by intrinsic stress. Furthermore, NCAM is suggested to participate in some of the bidirectional effects of stress on memory processes, with its enhanced synaptic expression involved in facilitating stress actions while its reduced expression being related to impairing effects of stress on memory function.

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“…The defense strategy employed depends on the context and the proximity of the threat (Blanchard and Blanchard, 1989;Fanselow, 1994;Kavaliers and Choleris, 2001;Wiedenmayer, 2004). Many laboratory fear procedures rely on a single measure, typically freezing (Blanchard and Blanchard, 1989).…”

Section: Summary Of Resultsmentioning

confidence: 99%

“…Even at young ages, animals can recognize and respond to threatening situations in an adaptive way (Hofer, 1995;Wiedenmayer andBarr, 1998, 2001b). Yet little is known of the neural substrate of fear regulation early in life.…”

Section: Introductionmentioning

confidence: 99%

Medial Prefrontal Cortex Processes Threatening Stimuli in Juvenile Rats

Kabitzke

Barr

Chan

et al. 2014

Neuropsychopharmacol

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To survive, all mammalian species must recognize and respond appropriately to threatening stimuli. In adults, the prelimbic medial prefrontal cortex (mPFC) appears to be involved in fear expression, whereas the infralimbic mPFC mediates fear extinction. In juvenile rats (PN26), the mPFC receives information on potential predators but does not act on it. To test whether the prefrontal cortex is capable of fear regulation in the young organism, we exposed juvenile rats to a threatening or nonthreatening stimulus and assessed fear and brain Fos activation of the mPFC subdivisions, amygdala and periaqueductal gray (PAG). In response to the threat, juveniles froze more, spent more time far from the threat, and had elevated numbers of Fos-positive cells in the prelimbic mPFC, the medial amygdala, and ventral PAG. To test the hypothesis that the mPFC has a dual role in modulating the amygdala and PAG in juveniles, we pharmacologically disinhibited each of the two subdivisions of the mPFC and assessed freezing and downstream activation to the threat. Juvenile rats infused with picrotoxin into the prelimbic mPFC and exposed to a threatening stimulus froze less, spent less time far from the threat, and increased Fos expression. Infusion of picrotoxin into the infralimbic mPFC also reduced fear responding to the threatening stimulus but had no effect on Fos expression. In sum, it appears that the mPFC can process threatening stimuli in juveniles at this age, even though it is normally not involved in the fear responses.

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Adaptations or pathologies? Long-term changes in brain and behavior after a single exposure to severe threat

Cited by 51 publications

References 104 publications

Nonassociative learning processes determine expression and extinction of conditioned fear in mice

Nonassociative learning processes determine expression and extinction of conditioned fear in mice

Learning under stress: A role for the neural cell adhesion molecule NCAM

Medial Prefrontal Cortex Processes Threatening Stimuli in Juvenile Rats

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