959 resultados para CONDITIONED FEAR


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Hypocotyls from etiolated cucumber (Cucumis sativus L.) seedlings were gently abraded at their epidermal surface and cut segments were conditioned to develop competence for H2O2 elicitation. Alkaline hydrolysates of cutin from cucumber, tomato, and apple elicited H2O2 in such conditioned segments. The most active constituent of cucumber cutin was identified as dodecan-1-ol, a novel cutin monomer capable of forming hydrophobic terminal chains. Additionally, the cutin hydrolysates enhanced the activity of a fungal H2O2 elicitor, similar to cucumber surface wax, which contained newly identified alkan-1,3-diols. The specificity of elicitor and enhancement activity was further elaborated using some pure model compounds. Certain saturated hydroxy fatty acids were potent H2O2 elicitors as well as enhancers. Some unsaturated epoxy and hydroxy fatty acids were also excellent H2O2 elicitors but inhibited the fungal elicitor activity. Short-chain alkanols exhibited good elicitor and enhancer activity, whereas longer-chain alkan-1-ols were barely active. The enhancement effect was also observed for H2O2 elicitation by ergosterol and chitosan. The physiological significance of these observations might be that once the cuticle is degraded by fungal cutinase, the cutin monomers may act as H2O2 elicitors. Corrosion of cutin may also bring surface wax constituents in contact with protoplasts and enhance elicitation.

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The localization of sites of memory formation within the mammalian brain has proven to be a formidable task even for simple forms of learning and memory. Recent studies have demonstrated that reversibly inactivating a localized region of cerebellum, including the dorsal anterior interpositus nucleus, completely prevents acquisition of the conditioned eye-blink response with no effect upon subsequent learning without inactivation. This result indicates that the memory trace for this type of learning is located either (i) within this inactivated region of cerebellum or (ii) within some structure(s) efferent from the cerebellum to which output from the interpositus nucleus ultimately projects. To distinguish between these possibilities, two groups of rabbits were conditioned (by using two conditioning stimuli) while the output fibers of the interpositus (the superior cerebellar peduncle) were reversibly blocked with microinjections of the sodium channel blocker tetrodotoxin. Rabbits performed no conditioned responses during this inactivation training. However, training after inactivation revealed that the rabbits (trained with either conditioned stimulus) had fully learned the response during the previous inactivation training. Cerebellar output, therefore, does not appear to be essential for acquisition of the learned response. This result, coupled with the fact that inactivation of the appropriate region of cerebellum completely prevents learning, provides compelling evidence supporting the hypothesis that the essential memory trace for the classically conditioned eye-blink response is localized within the cerebellum.

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Contemporary therapeutic circles utilize the concept of anxiety to describe a variety of disorders. Emotional reductionism is a detriment to the therapeutic community and the persons seeking its help. This dissertation proposes that attention to the emotion of fear clarifies our categorization of particular disorders and challenges emotional reductionism. I propose that the emotion of fear, through its theological relationship to hope, is useful in therapeutic practice for persons who experience trauma and PTSD. I explore the differences between fear and anxiety by deconstructing anxiety. Through this process, I develop four categories which help the emotion of fear stand independent of anxiety in therapy. Temporality, behaviors, antidote and objects are categories which distinguish fear from anxiety. Together, they provide the impetus to explore the emotion of fear. Understanding the emotion of fear requires an examination of its neurophysiological embodiment. This includes the brain structures responsible for fear production, its defensive behaviors and the evolutionary retention of fear. Dual inheritance evolutionary theory posits that we evolved physically and culturally, helping us understand the inescapability of fear and the unique threats humans fear. The threats humans react to develop through subjective interpretations of experience. Sometimes threats, through their presence in our memories and imaginations, inhibit a person's ability to live out a preferred identity and experience hope. Understanding fear as embodied and subjective is important. Process theology provides a religious framework through which fear can be interpreted. In this framework, fear is developed as an adaptive human response. Moreover, fear is useful to the divine-human relationship, revealing an undercurrent of hope. In the context of the divine-human relationship fear is understood as an initial aim which protects a person from a threat, but also preserves them for novel future relationships. Utilizing a "double-listening" stance, a therapist hears the traumatic narrative and counternarratives of resistance and resilience. These counternarratives express an orientation towards hopeful futures wherein persons thrive through living out a preferred identity. A therapeutic practice incorporating the emotion of fear will utilize the themes of survival, coping and thriving to enable persons to place their traumatic narrative within their meaning systems.

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In the cs.index.zip file we provide an R script which let us plot the conditioned Gini (or skewness) coefficient used in the working paper entitled "On conditional skewness with applications in environmental data" submitted to Environmental and Ecological Statistics. On the other hand, the ReadMe.pdf explains how to use the cs.index.R script.

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The neurotransmitter dopamine (DA) plays an essential role in reward-related incentive learning, whereby neutral stimuli gain the ability to elicit approach and other responses. In an incentive learning paradigm called conditioned activity, animals receive a stimulant drug in a specific environment over the course of several days. When then placed in that environment drug-free, they generally display a conditioned hyperactive response. Modulating DA transmission at different time points during the paradigm has been shown to disrupt or enhance conditioning effects. For instance, blocking DA D2 receptors before sessions generally impedes the acquisition of conditioned activity. To date, no studies have examined the role of D2 receptors in the consolidation phase of conditioned activity; this phase occurs immediately after acquisition and involves the stabilization of memories for long-term storage. To investigate this possible role, I trained Wistar rats (N = 108) in the conditioned activity paradigm produced by amphetamine (2.0 mg/kg, intraperitoneally) to examine the effects of the D2 antagonist haloperidol (doses 0.10, 0.25, 0.50, 0.75, 1.0, & 2.0 mg/kg, intraperitoneally) administered 5 min after conditioning sessions. Two positive control groups received haloperidol 1 h before conditioning sessions (doses 1.0 mg/kg and 2.0 mg/kg). The results revealed that post-session haloperidol at all doses tested did not disrupt the consolidation of conditioned activity, while pre-session haloperidol at 2.0 mg/kg prevented acquisition, with the 1.0 mg/kg group trending toward a block. Additionally, post-session haloperidol did not diminish activity during conditioning days, unlike pre-session haloperidol. One possible reason for these findings is that the consolidation phase may have begun earlier than when haloperidol was administered, since the conditioned activity paradigm uses longer learning sessions than those generally used in consolidation studies. Future studies may test if conditioned activity can be achieved with shorter sessions; if so, haloperidol would then be re-tested at an earlier time point. D2 receptor second messenger systems may also be investigated in consolidation. Since drug-related incentive stimuli can evoke cravings in those with drug addiction, a better understanding of the mechanisms of incentive learning may lead to the development of solutions for these individuals.

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Russia’s annexation of Crimea and destabilization of Ukraine have created a new context for Kazakhstan’s foreign and domestic policy. The ongoing crisis in the relations with Russia and the West has also changed the current order in the entire post-Soviet area. From Astana’s perspective, the Kremlin’s policy towards Ukraine can be considered dangerous since it shows Russia’s determination to interfere with the domestic affairs of its neighbours in the pursuit of its own interests. Furthermore, this policy reveals and raises the price a country needs to pay for its potential attempts to break free from the Russian zone of influence. At present the biggest challenge for the authorities in Astana is the accelerated implementation of the idea of the Eurasian Union promoted by Moscow, which is to be another stage in the integration of post-Soviet states (presently Russia, Kazakhstan and Belarus). The signing of the Eurasian Union’s founding documents planned for late May 2014 and the launch of this organisation (scheduled for January 2015) is sure to bring Kazakhstan closer to Russia and simultaneously limit its economic and political independence. Nevertheless, Astana’s position in relations with Moscow will to a large extent depend on the new shape of the relations between Russia and China. China is pursuing its own strategic interests in Central Asia (including in the energy sector) and its main partner in the region is Kazakhstan. At the domestic level, Russia’s actions in Ukraine made the authorities in Astana fear that measures similar to those used in Ukraine could be applied towards Kazakhstan. On the one hand this has led to increased efforts aimed at consolidating the state and strengthening its structures, and on the other hand it has brought about a revision of those aspects of domestic policy which Russia could interpret as a pretext for interfering.