Extinction Of Behavior Research Articles

Instrumental learning and behavioral persistence in children with attention-deficit/hyperactivity-disorder: does reinforcement frequency matter?

Prominent theoretical accounts of attention-deficit/hyperactivity-disorder (ADHD) hypothesize that reinforcement learning deficits underlie symptoms of ADHD. The Dynamic Developmental Theory and the Dopamine Transfer Deficit hypothesis assume impairments in both the acquisition and extinction of behavior, especially when learning occurs under partial (non-continuous) reinforcement, and subsequently the Partial Reinforcement Extinction Effect (PREE). Few studies have evaluated instrumental learning in ADHD and the results are inconsistent. The current study investigates instrumental learning under partial and continuous reinforcement schedules and subsequent behavioral persistence when reinforcement is withheld (extinction) in children with and without ADHD. Large well-defined samples of children with ADHD (n = 93) and typically developing (TD) children (n = 73) completed a simple instrumental learning task. The children completed acquisition under continuous (100%) or partial (20%) reinforcement, followed by a 4-min extinction phase. Two-way (diagnosis by condition) ANOVAs evaluated responses needed to reach the learning criterion during acquisition, and target and total responses during extinction. Children with ADHD required more trials to reach criterion compared to TD children under both continuous and partial reinforcement. After partial reinforcement, children with ADHD executed fewer target responses during extinction than TD children. Children with ADHD executed more responses than TD children during extinction, irrespective of learning condition. The findings demonstrate general difficulties in instrumental learning in ADHD, that is, slower learning irrespective of reinforcement schedule. They also show faster extinction following learning under partial reinforcement in those with ADHD, that is, a diminished PREE. Children with ADHD executed more responses during extinction. Results are theoretically important, with clinical implications for understanding and managing learning difficulties in those with ADHD, as they suggest poorer reinforcement learning and lower behavioral persistence.

A finite time extinction profile and optimal decay for a fast diffusive doubly nonlinear equation

In this article, we consider a fast diffusive type doubly nonlinear parabolic equation and study the extinction behavior of a solution at a finite time. We show the complete extinction of a weak solution with a nonnegative initial datum, that is, a weak solution is positive before a finite time and vanishes after it, and derive the optimal decay estimates of extinction. Our key ingredient of the proof is a nonlinear intrinsic scaling and the expansion of positivity.

Global Existence and Extinction Behaviour for a Doubly Nonlinear Parabolic Equation with Logarithmic Nonlinearity

This paper is mainly focused on the global existence and extinction behaviour of the solutions to a doubly nonlinear parabolic equation with logarithmic nonlinearity. By making use of energy estimates method and a series of ordinary differential inequalities, the global existence of the solution is obtained. Moreover, we give the sufficient conditions on the occurrence (or absence) of the extinction behaviour.

Optical investigation and computational modelling of BaTiO3 for optoelectronic devices applications

ABX3 perovskite-based materials have attracted research attention in various electronic and optoelectronic applications. The ability to tune the energy band gap through various dopants makes perovskites a potential candidate in many implementations. Among various perovskite materials, BaTiO3 has shown great applicability as a robust UV absorber with an energy band gap of around 3.2 eV. Herein, we provide a new sonochemical-assisted solid-phase method for preparing BaTiO3 thin films that optoelectronic devices can typically be used. BaTiO3 nano-powder and the thin film deposited on a glass substrate were characterized using physicochemical and optical techniques. In addition, the work demonstrated a computational attempt to optically model the BaTiO3 from the atomistic level using density functional theory to the thin film level using finite difference time domain Maxwell's equation solver. Seeking repeatability, the dispersion and the extinction behavior of the BaTiO3 thin film have been modeled using Lorentz-Dude (LD) coefficients, where all fitting parameters are listed. A numerical model has been experimentally verified using the experimental UV–Vis spectrometer measurements, recording an average root-mean-square error of 1.44%.

Distinct suppressing effects of deep brain stimulation in the orbitofrontal cortex on the development, extinction, and reinstatement of methamphetamine-seeking behaviors

AimsThe orbitofrontal cortex (OFC) is implicated in compulsive drug-seeking and relapse, the characteristics that result in addiction treatment failure. Structural and functional impairments within the OFC have been detected in many substance use disorders (SUDs). Deep brain stimulation (DBS) is proposed as a promising therapeutic option in treating SUDs. Therefore, the present study aimed to investigate the potential efficacy of DBS application on the various stages of the methamphetamine-conditioned place preference (CPP) paradigm in rats. Main methodsElectrodes were implanted unilaterally in the rat's right OFC. DBS in the form of high- or low-frequency stimulation (HFS: 130 Hz, LFS: 13 Hz) was applied during the 5-day conditioning phase (a daily 30-min session) or extinction period (30-min session, daily, ten days) of methamphetamine-induced CPP in two separate sets of experiments. Following extinction, place preference was reinstated by injecting a priming dose of methamphetamine (0.25 mg/kg). Key findingsThe HFS and LFS significantly decreased the methamphetamine place preference when applied over the conditioning period. In the extinction experiment, only HFS could remarkably accelerate the extinction of reward-context associations and even reduce the methamphetamine-induced reinstatement of seeking behaviors. SignificanceConclusively, DBS administration in the OFC demonstrated some positive results, including suppressing effects on the development, maintenance, and relapse of methamphetamine-seeking behavior. These findings encourage conducting more preclinical studies to strongly suggest a wide range of DBS applications in cortical areas such as OFC as an efficient treatment modality for psychostimulant use disorder.

JWST’s PEARLS: Dust Attenuation and Gravitational Lensing in the Backlit-galaxy System VV 191

We derive the spatial and wavelength behavior of dust attenuation in the multiple-armed spiral galaxy VV 191b using backlighting by the superimposed elliptical system VV 191a in a pair with an exceptionally favorable geometry for this measurement. Imaging using the James Webb Space Telescope and Hubble Space Telescope spans the wavelength range 0.3–4.5 μm with high angular resolution, tracing the dust in detail from 0.6–1.5 μm. Distinct dust lanes continue well beyond the bright spiral arms, and trace a complex web, with a very sharp radial cutoff near 1.7 Petrosian radii. We present attenuation profiles and coverage statistics in each band at radii 14–21 kpc. We derive the attenuation law with wavelength; the data both within and between the dust lanes clearly favor a stronger reddening behavior (R = A V /E B−V ≈ 2.0 between 0.6 and 0.9 μm, approaching unity by 1.5 μm) than found for starbursts and star-forming regions of galaxies. Power-law extinction behavior ∝λ −β gives β = 2.1 from 0.6–0.9 μm. R decreases at increasing wavelengths (R ≈ 1.1 between 0.9 and 1.5 μm), while β steepens to 2.5. Mixing regions of different column density flattens the wavelength behavior, so these results suggest a different grain population than in our vicinity. The NIRCam images reveal a lens arc and counterimage from a background galaxy at z ≈ 1, spanning 90° azimuthally at 2.″8 from the foreground elliptical-galaxy nucleus, and an additional weakly lensed galaxy. The lens model and imaging data give a mass/light ratio M/L B = 7.6 in solar units within the Einstein radius 2.0 kpc.

Dynamics of a diffusive viral infection model with impulsive CTL immune response

To explore the impacts of pulse vaccination on the dynamical behaviors of virus, the current paper investigates the persistence and global attractivity of a diffusive viral infection model incorporated with impulsive CTL immune response while the stronger logistic growth mechanism. Based on the comparison principle and the proper upper and lower solutions, we first discuss the existence of the infection-free steady state, and define the crucial CTL-activated viral infection reproduction number R 0 . Then, the fundamental extinction and uniform persistence behaviors of virus are distinguished by various cases of the threshold parameter R 0 . Finally, the existence and global attractivity of the positive steady state are still established by employing Brouwer's fixed point theorem and auxiliary functional. Our results indicate that high vaccination rates will stimulate the CTL response more effectively, and thus eventually can force the virus to eradicate.

The antidepressant agomelatine attenuates morphine-induced reinstatement but not self-administration or precipitated withdrawal

BackgroundExogenous melatonin appears to have anti-addictive properties and was recently shown to improve mental health and metabolic measures in patients receiving chronic opioid maintenance therapy. Agomelatine is a marketed antidepressant which acts as a melatonin agonist. We evaluated its effects using a rat model of morphine-reinforced behavior. MethodsAfter pretreatment with noncontingent morphine, male Wistar rats were trained to self-administer intravenous morphine (1.0 mg/kg-injection) under a progressive-ratio schedule. Rats were pretreated with vehicle or agomelatine during extinction, reinstatement, and reacquisition of morphine-reinforced behavior. ResultsDaily treatment with 10 mg/kg-day of agomelatine decreased the number of ratios completed and prolonged latency during morphine-induced reinstatement. There were no significant effects on cue-induced reinstatement, morphine self-administration, or naloxone-precipitated withdrawal. Treatment with 32 mg/kg-day of agomelatine caused postural changes. That dose prolonged withdrawal-induced loss of body weight and caused delayed reductions in food reinforcement. SummaryIn addition to postural effects, high-dose agomelatine worsened the course of spontaneous withdrawal and produced nonspecific effects on food-reinforced behavior. When administered at a selective dose, agomelatine did not modify morphine self-administration or precipitated withdrawal, but decreased morphine-induced reinstatement. Our findings show potential detrimental effects of high-dose agomelatine, with reductions in opioid-seeking behavior after a lower, more selective dose.

Infralimbic Projections to the Nucleus Accumbens Shell and Amygdala Regulate the Encoding of Cocaine Extinction Learning.

Prior evidence indicates that the infralimbic cortex (IL) mediates the ongoing inhibition of cocaine seeking following self-administration and extinction training in rats, specifically through projections to the nucleus accumbens shell (NAshell). Our own data indicate that IL activity immediately following an unreinforced lever press is critical for encoding the extinction contingencies in such procedures. Whether extinction encoding requires activity in the IL exclusively or also activity in its outputs, such as those to the NAshell and amygdala, is unknown. To address this issue, we used a closed-loop optogenetic approach in female and male Sprague Dawley rats to silence IL-NAshell or IL-amygdala activity following an unreinforced lever press during extinction training. Optical illumination (20 s) was given either immediately after a lever press or following a 20 s delay. IL-NAshell inhibition immediately following an unreinforced lever press increased lever pressing during extinction training and impaired retention of extinction learning, as assessed during subsequent extinction sessions without optical inhibition. Likewise, IL-amygdala inhibition given in the same manner impaired extinction retention during sessions without inhibition. Control experiments indicate that critical encoding of extinction learning does not require activity in these pathways beyond the initial 20 s post-lever press period, as delayed IL-NAshell and IL-amygdala inhibition had no effect on extinction learning. These results suggest that a larger network extending from the IL to the NAshell and amygdala is involved in encoding extinction contingencies following cocaine self-administration.SIGNIFICANCE STATEMENT Infralimbic cortex (IL) activity following an unreinforced lever press during extinction learning encodes the extinction of cocaine-seeking behavior. However, the larger circuitry controlling such encoding has not been investigated. Using closed-loop optogenetic pathway targeting, we found that inhibition of IL projections to the nucleus accumbens shell and to the amygdala impaired the extinction of cocaine seeking. Importantly, these effects were only observed when activity was disrupted during the first 20 s post-lever press and not when given following a 20 s delay. These findings suggest that successful cocaine extinction encoding requires activity across a larger circuit beyond simply inputs to the IL.

Raman amplification for trapped radiation in crystalline single Si nanoparticle

In a single crystalline Si particle, we observed a huge amplification of the Raman peak at 521 cm−1. With an AFM microscope, coupled with a Micro-Raman spectrometer, we investigate a single Si particle at wavelengths of 532 nm, 633 nm, and 785 nm. As observed by transmission electron microscopy, it has an octahedral shape of 150 nm in size. Thermal effects were detected on the Raman peak when the laser radiation, trapped inside, determines the heating of the particle up to its fusion. In these cases, the Raman peak splits into two components, the first at the crystal position and the other shifted at a lower value. The data permit the identification of the amplification mechanism of the Raman peak as trapped radiation moving forward and backwards into the particle. The thermal effects are attributed to phonon confinement and reduced thermal exchange with the surrounding. The present results are discussed in light of local order, the uncertainty principle, and phonon dispersion curves, and corroborated by shape-dependent simulation of absorption, scattering, and extinction behaviour.

The effectiveness of extinction training in male rats: Temporal considerations and brain mechanisms

The extinction of conditioned fear is frequently used in laboratories as a model for human exposure therapy and is crucial for studies of posttraumatic stress disorder (PTSD). However, the efficacy of specific protocols can vary greatly, and the underlying brain mechanisms are not sufficiently clarified. To address this issue, variable starting time (one or twenty-eight days after fear conditioning) and extinction protocols were used, and the efficacy and durability of fear extinction were also studied. Changes in the behavior, stress hormone levels and neuronal activation patterns of stressed rats were analyzed. Conditioned fear was rapidly and efficiently extinguished by all the protocols investigated. However, when these extinction protocols were initiated one day after fear training, conditioned fear relapsed spontaneously four weeks later. In contrast, when extinction trials were started 28 days after conditioning, no relapse occurred. Hormone measurements taken by the end of extinction trials indicated that adrenocorticotropin, but not corticosterone responses reflected behavioral extinction without any sign of relapse. The last extinction training increased the activation of the medial prefrontal cortex and decreased the activation of the central and medial amygdala when extinction began one day after fear conditioning. By contrast, the activation of the basolateral amygdala and the entire hippocampus decreased by the last training session when extinction started 28 days after fear conditioning. Our findings show that extinction training can extinguish remote fear memories more effectively than recent ones, and that the brain mechanisms underlying remote and recent fear memory extinction differ. Laboratory models should also focus on a later time point to increase their translational value.

Rhodium-embedded UV photodetectors based on localized surface plasmon resonance on AlN/GaN.

We report a remarkably enhanced responsivity of metal-semiconductor-metal photodetectors embedded with a large-scale periodicity and highly uniform rhodium nanoparticle array based on localized surface plasmon resonance. In this study, we used theoretical simulations of the absorption, scattering, and extinction behaviors, as well as the near electromagnetic field distributions to predict the plasmon resonance wavelength of quasi-triangular-shaped rhodium nanoparticles. More specifically, we successfully implemented a hexagonal close-packed structure with the individual quasi-triangular-shaped rhodium nanoparticle on the AlN/GaN structure by self-assembly nanosphere technology. The characterization results showed that the device embedded with rhodium nanoparticles had a reduced dark current of 7 × 10-14 A, and the maximum responsivity was shifted to a longer wavelength of approximately 310 nm compared to the device without rhodium nanoparticles. Moreover, at a wavelength of 324 nm, the enhancement ratio of the responsivity was as high as 56. Our study makes a significant contribution to the literature with a highly uniform, large-scale distributed rhodium nanoparticle array for enhancing the performance of AlGaN-based photodetectors in the UV region.

Reinforcement and extinction of unethical pro-supervisor behavior: Based on the perspective of supervisor response

Reinforcement and extinction of unethical pro-supervisor behavior: Based on the perspective of supervisor response

Modeling and analysis of a stochastic giving-up-smoking model with quit smoking duration.

Smoking has gradually become a very common behavior, and the related situation in different groups also presents different forms. Due to the differences of individual smoking cessation time and the interference of environmental factors in the spread of smoking behavior, we establish a stochastic giving up smoking model with quit-smoking duration. We also consider the saturated incidence rate. The total population is composed of potential smokers, smokers, quitters and removed. By using Itô's formula and constructing appropriate Lyapunov functions, we first ensure the existence of a unique global positive solution of the stochastic model. In addition, a threshold condition for extinction and permanence of smoking behavior is deduced. If the intensity of white noise is small, and $ \widetilde{\mathcal{R}}_0 < 1 $, smokers will eventually become extinct. If $ \widetilde{\mathcal{R}}_0 > 1 $, smoking will last. Then, the sufficient condition for the existence of a unique stationary distribution of the smoking phenomenon is studied as $ R_0^s > 1 $. Finally, conclusions are explained by numerical simulations.

Prenatal alcohol exposure enhanced alcohol preference and susceptibility to PTSD in a sex-dependent manner through the synaptic HCN1 channel

BackgroundPrenatal alcohol exposure (PAE) adversely affects the neurobiological and behavioral functions of offspring. Increasing evidence indicates that alcohol-use disorders and post-traumatic stress disorder (PTSD) commonly co-occur. Enhanced function of hyperpolarization-activated gated channel 1 (HCN1) may be involved in the pathogenesis of PTSD. This study aimed to explore the effect of PAE on fear extinction, spontaneous recovery, alcohol preference, and function of HCN1 channels in offspring of both sexes. MethodsThe PAE model was established with a 20 % (m/V) ethanol solution, and offspring were treated with 0.5, 1, and 2 μg/mL ZD7288 to block the HCN1 channel. Behavioral tests were used to detect the mental state and fear of extinction of the mice. Western blot was used to detect HCN1 expression in the synaptosomes. The BDNF/TrkB-pmTOR pathway was also examined. ResultsZD7288 administration ameliorated PAE-induced impairment of fear extinction and depression-like behavior. ZD7288 administration also alleviated PAE-induced inhibition of the HCN1 channel in the prefrontal cortex (PFC) and the BDNF/TrkB-pmTOR pathway in the hippocampus of offspring. In addition, the therapeutic effect of ZD7288 in males was better than that in females. ConclusionsOverall, these results suggest that PAE enhances alcohol preference and susceptibility to PTSD through synaptic HCN1 channels in the PFC. In addition, ZD7288 may be a promising candidate for preventing alcohol-associated PTSD-like syndrome, particularly in males. LimitationsThe effects of ZD7288 were only studied in PAE animals and not in healthy animals.

Mitragynine, a primary constituent of kratom reinstates morphine-seeking behaviour in rats.

Mitragynine (MG) is a pharmacologically active alkaloid derived from the leaves of Mitragyna speciosa Korth (Kratom). This plant has sparked significant interest as a potential alternative treatment for managing opioid dependence and withdrawal due to its opioid-like pharmacological effects. However, whether MG exposure would trigger opioid-seeking behaviour following abstinence has not been investigated. The present study examined the effects of MG priming on morphine-seeking behaviour in rats. Male Sprague-Dawley rats were initially trained to intravenously self-administer morphine (0.5 mg/kg/infusion) under a fixed ratio-3 schedule of reinforcement. Removal of both morphine infusions and drug-associated cues led to the subsequent extinction of the drug-seeking behaviour. Tests of reinstatement were made following exposure to a randomised order of intraperitoneal injections of MG (3, 10 and 30 mg/kg), morphine (5 mg/kg) and vehicle. Significant levels of drug-seeking behaviour were observed following extended access to morphine self-administration, which was extinguished following removal of morphine and cues indicative of morphine-seeking behaviour, supporting the relapse model. The present finding demonstrated that MG priming in a dose of 10 mg/kg resulted in the reinstatement of morphine-seeking behaviour, whereas the higher MG dose (30 mg/kg) tested suppressed the seeking response. This study indicated that exposure to a low MG dose may increase the likelihood of relapsing to opioids, suggesting that the potential of MG as a treatment for opioid management merits further scientific assessment of its ability to trigger relapse to opioid abuse.

Preparation and characterization of Co@C composites with good visible–far infrared extinction behaviors

Materials with excellent extinction performance can be synthesized by regulating the microstructure of carbon–based composites derived from metal–organic frameworks Herein, zeolitic imidazolate framework–67 (ZIF–67) was pyrolyzed at 400, 600, and 800 °C, forming Co@C-400, Co@C-600, and Co@C-800, respectively. At higher pyrolysis temperatures, the decomposed carbon skeleton exposed metal particles on the surface, which improved the extinction properties. Specimen Co@C-800 showed the highest absorption (above 95%) in the optical band. The average mass extinction coefficients of Co@C-800 in the 3–5 μm and 8–14 μm regions are 2.59 m2 g−1 and 2.22 m2 g−1, respectively, affirming the potential value of Co@C-800 in photo–thermal conversion and multiband stealth.

Distinct roles for orexin-1 and orexin-2 receptors in the dentate gyrus of the hippocampus in the methamphetamine-seeking behavior in the rats

Because of the relapsing properties of psychostimulants such as methamphetamine (Meth), there is no established pharmacotherapy for Meth addiction. The orexinergic system is a promising target for treating psychostimulant use disorders and relapse. However, to the best of our knowledge, no investigation regarding the role of orexin receptors in the dentate gyrus (DG) region of the hippocampus has been conducted in the extinction and reinstatement of Meth-seeking behavior. Two stainless-steel guide cannulae were bilaterally implanted into the DG of the rats' brains. The unbiased conditioned place preference (CPP) procedure was conducted to induce Meth conditioning. Following the five days Meth injections (1 mg/kg; sc), animals received intra-DG microinjection of SB334867 or TCS OX2 29, as orexin 1 (OX1) or orexin 2 (OX2) receptor antagonists, respectively (without Meth administration) during extinction phase to elucidate the role of orexin receptors in the latency of the extinction period in the Meth-conditioned rats. To evaluate the role of orexin receptors in the DG region in the reinstatement of Meth-seeking behavior, the extinguished rats received SB334867 or TCS OX2 29 before injecting a priming dose of Meth (0.25 mg/kg; sc). The results indicated two distinct roles for the OX1 and OX2 receptors in the DG region. TCS OX2 29 attenuated the extinction latency, and SB334867 considerably reduced the reinstatement of Meth-seeking behavior in this region. Therefore, the DG region's orexinergic system might be a potential therapeutic target for psychostimulant use disorders.

Counterflow flame extinction of ammonia and its blends with hydrogen and C1-C3 hydrocarbons

Ammonia as a fuel offers the potential to avoid carbon emissions, but its combustion is hindered by low reactivity. Here, the extinction limits of NH3 and NH3 plus reactivity enhancers were measured in the counterflow laminar non-premixed flames. A stable NH3-N2 flame was established with an oxygen-enriched oxidizer stream, and when the fuel was blended with CH4, C2H6, C3H8, and H2. For blended mixtures, results showed that CH4 has the least potential to enhance the stability of NH3 flames compared to the other additives. The extinction limits of C2H6 and C3H8 blended NH3 flames are nearly identical. At low percentage addition, H2-blended flames extinguish earlier than those blended with C1-C3 hydrocarbons, but this trend is reversed at higher H2 blends. Experimental conditions were simulated using Okafor et al. 2018 model and an extended Zhang et al 2021 model developed here. The models captured the measured trends, including the crossover between NH3-H2 and NH3-C2/C3 hydrocarbon fuels. Quantitatively, both models under-predicted the extinction limits of NH3-N2/enriched oxidizer flame. Better quantitative agreement is observed for the blended fuels using the model developed here. Discrepancies have been observed in the reported rates for reactions involving HNO (+OH, H), and if addressed, could improve models' capability in predicting extinction behavior in non-premixed flames. Numerical analyses were carried out to understand the kinetic coupling between NH3 and H2/C2-C3 in counter-flow flames. Extinction limits of NH3-C2-C3/H2 flames are shown to be affected by H abstraction and NH3 related chain termination reactions, heat producing reactions, and chain branching reactions. It has also been observed that at high blending ratios, C2H6/C3H8 addition in NH3 flames reduced the peak H and OH concentration via recombination and termination reactions, which compete with branching pathways. H2-blended flames are mostly influenced by reactions producing active radicals.

Infection Eradication Criterion in a General Epidemic Model with Logistic Growth, Quarantine Strategy, Media Intrusion, and Quadratic Perturbation

This article explores and highlights the effect of stochasticity on the extinction behavior of a disease in a general epidemic model. Specifically, we consider a sophisticated dynamical model that combines logistic growth, quarantine strategy, media intrusion, and quadratic noise. The amalgamation of all these hypotheses makes our model more practical and realistic. By adopting new analytical techniques, we provide a sharp criterion for disease eradication. The theoretical results show that the extinction criterion of our general perturbed model is mainly determined by the parameters closely related to the linear and quadratic perturbations as well as other deterministic parameters of the system. In order to clearly show the strength of our new result in a practical way, we perform numerical examples using the case of herpes simplex virus (HSV) in the USA. We conclude that a great amount of quadratic noise minimizes the period of HSV and affects its eradication time.