Regulatory Mechanisms of Fear Extinction and Depression-Like Behavior

refrontal Mechanisms in Extinction f Conditioned Fear

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...

Extinction of Recent Fear: Behavioral and Neural Mechanisms

Amount of fear extinction changes its underlying mechanisms

There has been a longstanding debate on whether original fear memory is inhibited or erased after extinction. One possibility that reconciles this uncertainty is that the inhibition and erasure mechanisms are engaged in different phases (early or late) of extinction. In this study, using single-session extinction training and its repetition (multiple-session extinction training), we investigate...

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...

Cannabinoid CB1 receptor mediates fear extinction via habituation-like processes.

The interplay between fear expression and fear extinction provides an important prerequisite for adequate coping with aversive encounters. Current models propose that extinction of conditioned fear is mediated by associative safety learning. Here, we demonstrate that the cannabinoid CB1 receptor, which is crucially involved in fear extinction, is dispensable for associative safety learning. In ...