Amygdala depotentiation and fear extinction.

Functionally Distinct Pools of Calcineurin Contribute to Depotentiation-like Synaptic Changes in the Lateral Amygdala During Auditory Fear Extinction

Different mechanisms of fear extinction dependent on length of time since fear acquisition.

Fear extinction is defined as a decline in conditioned fear responses (CRs) following nonreinforced exposure to a feared conditioned stimulus (CS). Behavioral evidence indicates that extinction is a form of inhibitory learning: Extinguished fear responses reappear with the passage of time (spontaneous recovery), a shift of context (renewal), and unsignaled presentations of the unconditioned sti...

Involvement of a calcineurin cascade in amygdala depotentiation and quenching of fear memory.

If fear memory is expressed by a long-term potentiation (LTP) of synaptic transmission in the amygdala, then reversal of LTP (depotentiation) in this area of the brain may provide an important mechanism for amelioration of anxiety and post-traumatic stress disorder. Herein, we show that low-frequency stimulation (LFS) of the external capsule elicits a depotentiation in the lateral nucleus of th...

Reversible Plasticity of Fear Memory-Encoding Amygdala Synaptic Circuits Even after Fear Memory Consolidation

It is generally believed that after memory consolidation, memory-encoding synaptic circuits are persistently modified and become less plastic. This, however, may hinder the remaining capacity of information storage in a given neural circuit. Here we consider the hypothesis that memory-encoding synaptic circuits still retain reversible plasticity even after memory consolidation. To test this, we...

Role of Amygdala-Infralimbic Cortex Circuitry in Glucocorticoid-induced Facilitation of Auditory Fear Memory Extinction

Introduction: The basolateral amygdala (BLA) and infralimbic area (IL) of the medial prefrontal cortex (mPFC) are two interconnected brain structures that mediate both fear memory expression and extinction. Besides the well-known role of the BLA in the acquisition and expression of fear memory, projections from IL to BLA inhibit fear expression and have a critical role in fear extinction. Howev...