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In recent years, attention has been given to the interaction between the emotional state of the animal and its ability to learn and remember. Studies into the neural mechanisms underlying these interactions have focused on stress-induced synaptic plasticity impairments in the hippocampus. However, other brain areas, including the amygdala and the prefrontal(More)
Once consolidated, a long-term memory item could regain susceptibility to consolidation blockers, that is, reconsolidate, upon its reactivation. Both consolidation and reconsolidation require protein synthesis, but it is not yet known how similar these processes are in terms of molecular, cellular, and neural circuit mechanisms. Whereas most previous(More)
We have previously shown that high-frequency stimulation to the basolateral amygdala (BLA) induces long-term potentiation (LTP) in the ventromedial prefrontal cortex (vmPFC) and that prior exposure to inescapable stress inhibits the induction of LTP in this pathway [Maroun & Richter-Levin (2003)J. Neurosci., 23, 4406-4409]. Here, we show that the reciprocal(More)
In auditory fear conditioning, repeated presentation of the tone in the absence of the shock leads to extinction of the acquired fear response. Both the infra limbic prefrontal cortex (IL) and the basolateral amygdala (BLA) are involved in extinction. In this study, we examine the involvement of these two regions in extinction by manipulating the(More)
Stress-sensitive psychopathologies such as post-traumatic stress disorder are characterized by deficits in fear extinction and dysfunction of corticolimbic circuits mediating extinction. Chronic stress facilitates fear conditioning, impairs extinction, and produces dendritic proliferation in the basolateral amygdala (BLA), a critical site of plasticity for(More)
We have used frequency-dependent inhibition, a form of short-term plasticity mediated by the activation of inhibitory interneurons, to characterize in vivo alterations in local circuit activity and plasticity in the dentate gyrus of the anesthetized rat. The application of the GABA-A receptor blocker, bicuculline, induced a transient reduction in(More)
Stress exposure, depending on its intensity and duration, affects cognition and learning in an adaptive or maladaptive manner. Studies addressing the effects of stress on cognitive processes have mainly focused on conditioned fear, since it is suggested that fear-motivated learning lies at the root of affective and anxiety disorders. Inhibition of(More)
This study examined the effects of the arousal level of the rat and exposure to a behavioral stressor on consolidation and reconsolidation of a nonaversive learning paradigm, the object recognition task. Learning was tested under two arousal conditions: no previous habituation to the experimental context (high novelty stress/arousal level) or extensive(More)
We investigated whether the N-methyl-D-aspartate (NMDA) receptor partial agonist D-cycloserine (DCS, 20 microg/side) microinfused into the basolateral amygdala (BLA) would reverse stress-induced impairment of extinction in two aversive learning paradigms: contextual fear conditioning and conditioned taste aversion (CTA). We found that DCS in the BLA show(More)
The dual impairment of both long-term potentiation (LTP) in the dentate gyrus and spatial memory by N-methyl-D-aspartate (NMDA) blockers such as 2-aminophosphonovaleric acid (APV) or dizocilpine (MK-801) is considered supportive evidence for the hypothesis that LTP-like mechanisms are involved in spatial memory. However, several studies suggest that, at(More)