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...

The neurobiological mechanisms that underlie the resistance of drug cue associations to extinction in addiction remain unknown. Fear extinction critically depends on the ventromedial prefrontal cortex (VMPFC). Here, we tested if this same region plays a role in extinction of non-fear, drug and pleasant cue associations. Eighteen chronic cocaine users and 15 matched controls completed three func...

One strategy proposed to treat addictive disorders is to extinguish the association between environmental stimuli (cues) and actions associated with drug use to reduce relapse. The context specificity of extinction learning, however, impairs the ability of addicts to generalize extinction training to the drug-taking context. We previously reported that the NMDA receptor partial agonist d-cyclos...

Mie scattering lidar was used to observe aerosol extinction coefficient profiles in the troposphere over Tsukuba (140 E, 36 N), Japan, for three years from March 1990 to February 1993, and data obtained in fair weather were analyzed. The lidar measurements were made by a vertical scanning mode to generate profiles of extinction coefficients from the lidar level to a 12-km altitude. The extincti...

Studies of extinction in classical conditioning situations can reveal techniques that maximize the effectiveness of exposure-based behavior therapies. In three experiments, we investigated the effect of varying the intertrial interval during an extinction treatment in a fear-conditioning preparation with rats as subjects. In Experiment 1, we found less fear at test (i.e., more effective extinct...

We give explicit formulae for most likely paths to extinction in simple branching models when initial population is large. In discrete time, we study the Galton-Watson process, and in continuous time, the branching diffusion. Themost likely paths are found with the help of the large deviation principle (LDP). We also find asymptotics for the extinction probability, which gives a new expression ...

Environmental perturbations during mass extinctions were likely manifested differently in epicontinental seas than in open-ocean-facing habitats of comparable depth. Here, we present a dissection of origination and extinction in epicontinental seas versus open-ocean-facing coastal regions in the Permian through Cretaceous periods, an interval through which both settings are well represented in ...

An experiment using rats investigated whether retrieval cues for an extinction memory could also be brought under the control of cues not physically present during extinction learning. Following the extinction of a fear motivated task in a context different from original learning, rats were exposed to the training context either immediately, 30 min, or 60 min after extinction. When tested back ...

Fear extinction is impaired in neuropsychiatric disorders, including posttraumatic stress disorder. Identifying drugs that facilitate fear extinction in animal models provides leads for novel pharmacological treatments for these disorders. Zinc (Zn) is expressed in neurons in a cortico-amygdala circuit mediating fear extinction, and modulates neurotransmitter systems regulating extinction. We p...

BACKGROUND Despite its success in treating specific anxiety disorders, the effect of exposure therapy is limited by problems with tolerability, treatment resistance, and fear relapse after initial response. The identification of novel drug targets facilitating fear extinction in clinically relevant animal models may guide improved treatment strategies for these disorders in terms of efficacy, a...