Fear extinction correlates with increased infralimbic (IL) neuronal excitability. Since small conductance Ca(2+)-dependent K(+) (SK) channels modulate neuronal excitability and certain types of learning and memory, pharmacological modulation of SK channels could be used to regulate IL excitability and fear extinction. To test this, we first determined the effect of blocking SK channels with apa...

Mu-opioid receptors in the ventrolateral quadrant midbrain periaqueductal gray (vIPAG) contribute to extinction of conditioned fear. The present experiment studied whether fear extinction could be facilitated by infusions of a peptidase inhibitor that reduces catabolism of vIPAG enkephalins. Rats were trained to fear an auditory conditioned stimulus. Fear was then extinguished. Extinction train...

It is unclear whether protein phosphatases, which counteract the actions of protein kinases, play a beneficial role in the formation and extinction of previously acquired fear memories. In this study, we investigated the role of the calcium/calmodulin dependent phosphatase 2B, also known as calcineurin (CaN) in the formation of contextual fear memory and extinction of previously acquired contex...

Many factors account for how well individuals extinguish conditioned fears, such as genetic variability, learning capacity and conditions under which extinction training is administered. We predicted that memory-based interventions would be more effective to reduce the reinstatement of fear in subjects genetically predisposed to display more extinction learning. We tested this hypothesis in rat...

It has been reported that stress-related activation of the noradrenergic system strengthens the formation of aversive memories and that beta-adrenergic receptors seem to be involved in this emotional memory processing. In this study, the effects of beta-adrenergic compounds on the extinction of contextual conditioned fear responses were evaluated. Rats were trained with footshock in a condition...

The extinction of learned fear is a hippocampus-dependent process thought to embody new learning rather than erasure of the original fear memory, although it is unknown how these competing contextual memories are represented in the hippocampus. We previously demonstrated that contextual fear conditioning results in hippocampal place cell remapping and long-term stabilization of novel representa...

nterest in the medial prefrontal cortex (mPFC) as a source of behavioral inhibition has increased with the mounting evidence for a unctional role of the mPFC in extinction of conditioned fear. In fear extinction, a tone-conditioned stimulus (CS) previously paired ith a footshock is presented repeatedly in the absence of footshock, causing fear responses to diminish. Here, we review converging v...

Fear responses can be eliminated through extinction, a procedure involving the presentation of fear-eliciting stimuli without aversive outcomes. Extinction is believed to be mediated by new inhibitory learning that acts to suppress fear expression without erasing the original memory trace. This hypothesis is supported mainly by behavioral data demonstrating that fear can recover following extin...

Establishing the neurocircuitry involved in inhibiting fear is important for understanding and treating anxiety disorders. To date, extinction procedures have been predominately used to examine the inhibition of learned fear, where fear is reduced to a conditioned stimulus (CS) by presenting it in the absence of the unconditioned stimulus (US). However, learned fear can also be reduced by habit...

Objective/Hypothesis: Although now considered to be the most effective treatment for post traumatic stress disorder (PTSD), extinctionbased therapies require substantial time and investment for both the patient and provider, averaging 10 sessions or more of approximately 1h each to achieve significant beneficial effects. Thus, treatments that enhance the efficacy of extinction therapies and red...