Extinction in adult animals, including humans, appears to involve the medial prefrontal cortex (mPFC). However, the role of mPFC in extinction across development has not yet been studied. Given several recent demonstrations of developmental differences in extinction of conditioned fear at a behavioral level, different neural circuitries may mediate fear extinction across development. In all exp...

Rats were trained to run a straight-alley maze for an oral cocaine or sucrose vehicle solution reward, followed by either response or latent extinction training procedures that engage neuroanatomically dissociable "habit" and "cognitive" memory systems, respectively. In the response extinction condition, rats performed a runway approach response to an empty fluid well. In the latent extinction ...

Emerging research has demonstrated that the sex hormone estradiol regulates fear extinction in female rodents and women. Estradiol may also regulate fear extinction in males, given its role in synaptic plasticity in both sexes. Here we report that inhibition of estradiol synthesis during extinction training, via the aromatase inhibitor fadrozole, significantly impairs extinction recall in male ...

We have used UV (FOCA) and FIR (IRAS) images of six nearby late type galaxies to study the radial variation of the UV extinction (deduced from the FIR/UV ratio). We compare the UV extinction gradient with other extinction indicators (Balmer decrement) and search for a relation between the extinction, the metallicity and the gas surface density among our galaxies. We detect in our small sample a...

Introducing the effect of extinction into the so-called replicator equations in mathematical biology, we construct a general model of ecosystems. The present model shows mass extinction by its own extinction dynamics when the system initially has a large number of species (diversity). The extinction dynamics shows several significant features such as a power law in basin size distribution, indu...

When we hear the word extinction, most of us immediately think of dinosaurs and woolly mammoths and cataclysmic events precipitating their extinction. Some of us are also aware of current extinction threats and recent extinctions, but few, if any, of us understand the varying and complex circumstances under which extinction actually happens. It turns out that extinction and species survival are...

When we hear the word extinction, most of us immediately think of dinosaurs and woolly mammoths and cataclysmic events precipitating their extinction. Some of us are also aware of current extinction threats and recent extinctions, but few, if any, of us understand the varying and complex circumstances under which extinction actually happens. It turns out that extinction and species survival are...

We developed a database of 10 wild vertebrate populations whose declines to extinction were monitored over at least 12 years. We quantitatively characterized the final declines of these well-monitored populations and tested key theoretical predictions about the process of extinction, obtaining two primary results. First, we found evidence of logarithmic scaling of time-to-extinction as a functi...

General host-parasite theory suggests that parasites may be implicated in the extinction of their hosts by causing instability that leads to increased risk of stochastic extinction. In contrast, spatially explicit models suggest that the parasite may directly drive the host population to extinction. Here we examine the ecological characteristics of host-parasite interactions that favor parasite...

Biogeographic patterns of survival help constrain the causal factors responsible for mass extinction. To test whether biogeography influenced end-Cretaceous (K-Pg) extinction patterns, we used a network approach to delimit biogeographic units (BUs) above the species level in a globalMaastrichtian database of 329 bivalve genera. Geographic range is thought to buffer taxa from extinction, but the...