Relevant bibliographies by topics / Unconditioned and Conditioned Fear

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Academic literature on the topic 'Unconditioned and Conditioned Fear'

Author: Grafiati
Published: 4 June 2021
Last updated: 1 February 2022

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Journal articles on the topic "Unconditioned and Conditioned Fear"

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Hagsäter, S. Melker, Johan Thorén, Robert Pettersson, and Elias Eriksson. "Selective serotonin reuptake inhibition increases noise burst-induced unconditioned and context-conditioned freezing." Acta Neuropsychiatrica 31, no. 1 (2018): 46–51. http://dx.doi.org/10.1017/neu.2018.26.

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AbstractObjectiveWhereas long-term administration of selective serotonin reuptake inhibitors (SSRIs) is effective for the treatment of anxiety disorders, acute administration of these drugs may exert a paradoxical anxiogenic effect. The aim of the present study was to explore the possible effect of an SSRI in situations of unconditioned or limited conditioned fear.MethodsMale Sprague Dawley rats were administered a single dose of an SSRI, escitalopram, before acquisition or expression of context conditioned fear, where noise bursts were used as the unconditioned stimulus. Freezing was assessed as a measure of unconditioned fear (=the acute response to noise bursts) or conditioned fear (=the response to the context), respectively.ResultsNoise bursts elicited an acute increase in freezing but no robust conditioned response 7 days after exposure. Administration of escitalopram before testing exacerbated the freezing response during presentation of the unconditioned stimulus and also unmasked a conditioned response; in contrast, administration of escitalopram prior to acquisition did not influence the conditioned response.ConclusionThe data suggest that freezing in rats exposed to a stimulus inducing relatively mild fear may be enhanced by acute pretreatment with an SSRI regardless of whether the freezing displayed by the animals is an acute unconditioned response to the stimulus in question or a conditioned response to the same stimulus.
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Brandão, Marcus L., and Norberto C. Coimbra. "Understanding the role of dopamine in conditioned and unconditioned fear." Reviews in the Neurosciences 30, no. 3 (2019): 325–37. http://dx.doi.org/10.1515/revneuro-2018-0023.

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Abstract Pharmacological and molecular imaging studies in anxiety disorders have primarily focused on the serotonin system. In the meantime, dopamine has been known as the neurotransmitter of reward for 60 years, particularly for its action in the nervous terminals of the mesocorticolimbic system. Interest in the mediation by dopamine of the well-known brain aversion system has grown recently, particularly given recent evidence obtained on the role of D2 dopamine receptors in unconditioned fear. However, it has been established that excitation of the mesocorticolimbic pathway, originating from dopaminergic (DA) neurons from the ventral tegmental area (VTA), is relevant for the development of anxiety. Among the forebrain regions innervated by this pathway, the amygdala is an essential component of the neural circuitry of conditioned fear. Current findings indicate that the dopamine D2 receptor-signaling pathway connecting the VTA to the basolateral amygdala modulates fear and anxiety, whereas neural circuits in the midbrain tectum underlie the expression of innate fear. The A13 nucleus of the zona incerta is proposed as the origin of these DA neurons projecting to caudal structures of the brain aversion system. In this article we review data obtained in studies showing that DA receptor-mediated mechanisms on ascending or descending DA pathways play opposing roles in fear/anxiety processes. Dopamine appears to mediate conditioned fear by acting at rostral levels of the brain and regulate unconditioned fear at the midbrain level.
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Cavalcante, K. M. H. "Short-term but not long-term exposure to an enriched environment reduces unconditioned fear responses but not conditioned fear responses." Scientific Electronic Archives 12, no. 5 (2019): 86. http://dx.doi.org/10.36560/1252019933.

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Environmental enrichment (EE) has been shown to produce beneficial effects in animal models of a wide variety of neurological and psychiatric disorders. EE exhibits antidepressant function; reduces anxiety, improves spatial learning and memory impairment. EE can reduce sensitivity to loss of reward by reducing frustration-like emotional states and facilitates the extinction of conditioned fear. However, some studies related to the emotional effects of EE present controversial results such as reduction or increase in anxiety. The time of exposure to an enriched environment seems to be an important factor in the behavioral responses presented by animals subjected to aversive stimuli. The present study compared the effects of two and four week exposure to EE with young adult Wistar rats under the same conditions and protocol on fear behavioral parameters in the face of footshock (unconditioned fear) and on re-exposure to an environment after electrical shock pairing (conditioned fear). We showed that the EE with a duration of two weeks reduced the freezing response of the animals in an unconditioned fear situation, that is, with the aversive stimulus present in the environment, however, did not influence the same behavior in a conditioned fear situation. In addition, the short-term EE developed the locomotor and exploratory activity, identified by the high rearing behavior, which may also suggest a low level of anxiety in these animals. We can conclude that EE changes the unconditioned fear responses of young adult rats. In addition, the duration of EE interferes differently, being two weeks of treatment with EE sufficient to cause improvement in coping with unconditioned aversive situations. We suggest that the emotional benefits resulting from the welfare provided by EE can be abolished by the longer duration of this treatment, due to the already known effect of tolerance to lasting or abundant rewards.
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Chorot, Paloma, and Bonifacio Sandín. "Effects of UCS Intensity and Duration of Exposure of Nonreinforced CS on Conditioned Electrodermal Responses: An Experimental Analysis of the Incubation Theory of Anxiety." Psychological Reports 73, no. 3_part_1 (1993): 931–41. http://dx.doi.org/10.1177/00332941930733pt132.

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Eysenck's incubation theory of fear or anxiety was examined in a human Pavlovian conditioning experiment with skin-conductance responses as the dependent variable. The conditioned stimuli (CSs) were fear-relevant slides (snakes and spiders) and the unconditioned stimuli (UCSs) were aversive tones. Different groups of subjects were presented two tone intensities during the acquisition phase and three durations of nonreinforced CS (extinction phase) in a delay differential conditioning paradigm. Resistance to extinction of conditioned skin-conductance responses (conditioned fear responses) exhibited was largest for high intensity of tone and short presentations of the nonreinforced CS (CS + presented alone). The result tends to support Eysenck's incubation theory of anxiety.
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Wood, Kimberly H., Lawrence W. Ver Hoef, and David C. Knight. "Neural mechanisms underlying the conditioned diminution of the unconditioned fear response." NeuroImage 60, no. 1 (2012): 787–99. http://dx.doi.org/10.1016/j.neuroimage.2011.12.048.

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Paré, Denis, Gregory J. Quirk, and Joseph E. Ledoux. "New Vistas on Amygdala Networks in Conditioned Fear." Journal of Neurophysiology 92, no. 1 (2004): 1–9. http://dx.doi.org/10.1152/jn.00153.2004.

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It is currently believed that the acquisition of classically conditioned fear involves potentiation of conditioned thalamic inputs in the lateral amygdala (LA). In turn, LA cells would excite more neurons in the central nucleus (CE) that, via their projections to the brain stem and hypothalamus, evoke fear responses. However, LA neurons do not directly contact brain stem-projecting CE neurons. This is problematic because CE projections to the periaqueductal gray and pontine reticular formation are believed to generate conditioned freezing and fear-potentiated startle, respectively. Moreover, like LA, CE may receive direct thalamic inputs communicating information about the conditioned and unconditioned stimuli. Finally, recent evidence suggests that the CE itself may be a critical site of plasticity. This review attempts to reconcile the current model with these observations. We suggest that potentiated LA outputs disinhibit CE projection neurons via GABAergic intercalated neurons, thereby permitting associative plasticity in CE. Thus plasticity in both LA and CE would be necessary for acquisition of conditioned fear. This revised model also accounts for inhibition of conditioned fear after extinction.
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Mueller, Erik M., Matthias F. J. Sperl, and Christian Panitz. "Aversive Imagery Causes De Novo Fear Conditioning." Psychological Science 30, no. 7 (2019): 1001–15. http://dx.doi.org/10.1177/0956797619842261.

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In classical fear conditioning, neutral conditioned stimuli that have been paired with aversive physical unconditioned stimuli eventually trigger fear responses. Here, we tested whether aversive mental images systematically paired with a conditioned stimulus also cause de novo fear learning in the absence of any external aversive stimulation. In two experiments ( N = 45 and N = 41), participants were first trained to produce aversive, neutral, or no imagery in response to three different visual-imagery cues. In a subsequent imagery-based differential-conditioning paradigm, each of the three cues systematically coterminated with one of three different neutral faces. Although the face that was paired with the aversive-imagery cue was never paired with aversive external stimuli or threat-related instructions, participants rated it as more arousing, unpleasant, and threatening and displayed relative fear bradycardia and fear-potentiated startle. These results could be relevant for the development of fear and related disorders without trauma.
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Sandin, Bonifacio, and Paloma Chorot. "Resistance to Extinction of Conditioned Electrodermal Responses: A Study of the Incubation Fear Hypothesis." Psychological Reports 91, no. 1 (2002): 37–46. http://dx.doi.org/10.2466/pr0.2002.91.1.37.

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In the present study we examined Eysenck's incubation hypothesis of fear. Probability of skin conductance response (SCR) was analyzed for a sample of 79 undergraduate women, ranging in age from 18 to 25 years. Different groups of participants were conditioned to two levels of unconditioned stimuli (UCS) intensity and presented to three levels of unreinforced conditioned stimuli (CS) exposures (extinction phase) in a delay differential conditioning paradigm. The CSs were fear-relevant slides (snakes and spiders) and the UCSs were aversive tones. Analysis did not show a clear incubation effect; instead an increased resistance to extinction of SCR probability in association to the high-UCS and the short unreinforced CS presentation was evident. Findings support partially Eysenck's incubation theory of fear/anxiety.
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Wood, Kimberly H., Dystany Kuykendall, Lawrence W. Ver Hoef, and David C. Knight. "Neural Substrates Underlying Learning-Related Changes of the Unconditioned Fear Response." Open Neuroimaging Journal 7, no. 1 (2013): 41–52. http://dx.doi.org/10.2174/1874440001307010041.

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The ability to predict an impending threat during Pavlovian conditioning diminishes the emotional response that is produced once the threat is encountered. Diminution of the threat response appears to be mediated by somewhat independent associative learning and expectancy-related processes. Therefore, the present study was designed to better understand the neural mechanisms that support associative learning processes, independent of expectancy, that influence the emotional response to a threat. Healthy volunteers took part in a Pavlovian conditioning procedure during which trait anxiety, expectation of the unconditioned stimulus (UCS), skin conductance response (SCR), and functional magnetic resonance imaging (fMRI) signal were assessed. The results showed no evidence for associative learning that was independent of expectation. Threat-related SCR expression was diminished on predictable trials vs. unpredictable trials of the UCS (i.e. conditioned UCR diminution). Similar to SCR, conditioned UCR diminution was observed within the left dorsolateral PFC, dorsomedial PFC, ventromedial PFC, and left anterior insula. In contrast, potentiation of the threat-related fMRI signal response was observed within left dorsolateral PFC, inferior parietal lobule (IPL), and posterior insula. A negative relationship was observed between UCS expectancy and UCR expression within the dorsomedial PFC, ventromedial PFC, and anterior insula. Finally, the anticipatory fMRI signal responses within the PFC, posterior cingulate, and amygdala showed an inverse relationship with threat-related activation within the brain regions that showed UCR diminution. The current findings suggest that the PFC and amygdala support learning-related processes that impact the magnitude of the emotional response to a threat.
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Åsli, Ole, and Magne Arve Flaten. "How Fast is Fear?" Journal of Psychophysiology 26, no. 1 (2012): 20–28. http://dx.doi.org/10.1027/0269-8803/a000063.

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The minimum latency of potentiated startle after delay and trace fear conditioning was investigated. Delay conditioning is hypothesized to be mediated by automatic processes, whereas trace conditioning is hypothesized to involve controlled cognitive processes. In a group receiving delay conditioning, a tone conditioned stimulus (CS) signaled an electric shock unconditioned stimulus (US) presented 1,000 ms after CS onset. In a group receiving trace conditioning, a 200 ms tone CS was followed by an 800 ms gap prior to US presentation. Two control groups received unpaired CS/US presentations. It was hypothesized that fear-potentiated startle should be observed at shorter time intervals after CS onset in the group receiving delay conditioning compared to the group receiving trace conditioning. The results showed increased startle at 100 and 150 ms after CS onset in the group receiving delay conditioning compared to the unpaired group. In the group receiving trace conditioning, increased startle was observed at 1,500 ms after CS onset compared to the unpaired group. This supports the idea that conditioned fear after delay conditioning may be due to automatic processes, whereas trace conditioning is dependent on controlled processes.
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Dissertations / Theses on the topic "Unconditioned and Conditioned Fear"

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Li, Chun-I. "Distinct roles of the medial and central nucleus of the amygdala in unconditioned and conditioned fear." Thesis, University of Hawaii at Manoa, 2003. http://hdl.handle.net/10125/7108.

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Pre-clinical and clinical data suggest that the amygdala plays a role in the detection of emotional events and in the production of fear responses. The amygdala is composed of distinct nuclei that may serve different functional roles in the modulation of fear. The present study examined the roles of the medial (MeA) and central (CeA) nucleus of the amygdala in unconditioned and conditioned fear. Following bilateral ibotenic acid lesions of the MeA or CeA, rats were exposed to cat odor, an unconditioned fear stimulus. In comparison with sham-operated controls, rats with MeA lesions exhibited significant deficits in cat odor-induced unconditioned fear as indicated by a significant reduction in the duration of freezing and avoidance and an increase in the frequency of contact with the cat odor stimulus. In contrast, excitotoxic lesions of the CeA had no significant effects on cat odor-induced unconditioned fear. To examine the role of the MeA and CeA in conditioned fear, rats with similar fiber-sparing lesions of the MeA and CeA were exposed to foot-shock. Conditioned freezing was measured in the immediate post-shock period and a retention test administered after 24-h. Results indicated that MeA lesions had no reliable effects on contextual fear conditioning as indicated by no significant differences in freezing between lesion and control groups in the immediate post-shock period and in the retention test. In contrast, CeA lesions produced significant deficits in freezing occurring in the post-Shock interval and in the retention test. Together, these results suggest that the MeA, but not the CeA, plays a role in the mediation of predator odor-induced unconditioned fear. In contrast, the CeA, but not the MeA, appears to playa role in fear conditioning to a context paired with electric foot-shock.<br>vii, 40 leaves
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Barnett, Scott Thomas Charles. "Glutamate receptors in the ventral tegmental area : a potential mechanism involved in long term potentiation : a thesis submitted in partial fulfilment of the requirements of the degree of Masters of Science in Psychology at the University of Canterbury /." Thesis, University of Canterbury. Psychology, 2006. http://hdl.handle.net/10092/1358.

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In the present study, footshock, which produces a powerful aversive emotional response was used in a Pavlovian conditioning experiment as an unconditioned stimulis (UCS), and was paired with the presentation of a light used as a conditioned stimulis (CS). There is an accumulation of evidence that supports the assertion that dopaminergic (DA) neurons within the ventral tegmental area (VTA) are active in processes that contribute to the amygdala-based circuitry involved in regulating emotionally salient responses. To build upon findings implicating VTA DA, excitatory glutamate (Glu), NMDA and AMPA receptors, were examined with respect to their role in Pavlovian conditioned fear responding. Fear potentiated startle (FPS) was used to assess the effects of intra-VTA infused AP5, and intra-VTA infused CNQX on conditioned fear responding in laboratory rats. The administration of the NMDA receptor antagonist AP5 (at 1.0, 2.5, and 5.0ug doses), blocked the ability of a conditioned stimulus (CS) previously paired with footshock to become conditioned to the UCS. Similarly, administration of the AMPA receptor antagonist CNQX (at 1.0, 2.5, 5.0ug doses), inhibited the ability of the CS to become conditioned to the UCS. The results of this study indicate the VTA is an important site for synaptic modifications associated with fear learning, and that activation of excitatory Glutamatergic receptors in the VTA play a necessary part of the processing underlying fear conditioning. Measures of shock reactivity demonstrated that the infusion of AP5 and CNQX into the VTA did not inhibit baseline startle amplitudes. The administration of AP5 and CNQX did not suppress the perception of footshock as an aversive stimulus. This study provides further definition to established knowledge surrounding the neural processes whereby neutral environmental cues gain negative emotional salience as occurs in fear conditioning. It was hypothesised that the action of excitatory glutamatergic transmission within the VTA acts on NMDA and AMPA receptors is to assist in the acquisition of Pavlovian conditioned fear, possibly through the same synaptic mechanisms that govern LTP.
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BALLESTEROS, CAROLINA IRURITA. "ROLE OF DORSAL AND VENTRAL HIPPOCAMPUS ON CONDITIONED AND UNCONDITIONED FEAR ELICITED BY DORSAL PERIAQUEDUCTAL GREY MATTER ELECTRICAL STIMULATION IN RATS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2012. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=19918@1.

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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO<br>Este estudo investiga o papel do hipocampo no comportamento de defesa condicionado e incondicionado examinando o efeito de lesões eletrolíticas pré-treino no hipocampo dorsal e ventral de ratos expostos a dois tipos de estímulos aversivos: estimulação elétrica da matéria cinzenta periaquedutal dorsal e choque nas patas. A lesão na parte dorsal e ventral diminuiu significativamente o comportamento defensivo condicionado. No comportamento defensivo incondicionado, a lesão ventral alterou significativamente o congelamento pré-fuga e a fuga. Os resultados sugerem um papel específico da parte dorsal e ventral do hipocampo na modulação de defesa através da utilização do modelo animal de ataque de pânico e TAG.<br>This study investigates the role of the hippocampus in both unconditioned and conditioned defense behavior by examining the effects of pre-training electrolytic lesions to the dorsal and ventral hippocampus in male rats exposed to two types of threat stimuli: electrical stimulation of the DPAG and footshock. Our results indicate that ventral and dorsal lesions significantly attenuated conditioned defensive behavior. During unconditioned trials, ventral hippocampal lesion altered threshold needed for escape and pre-escape freezing. These results suggest a specific role of the ventral and dorsal hippocampus in modulating GAD and panic-attack like behaviors in certain animal model of defense.
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Figueiredo, Rebeca Machado de. "Diferenças associadas ao ciclo estral na reatividade emocional de ratas a estímulos incondicionados e condicionados de medo." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/59/59134/tde-07112016-124538/.

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O desequilíbrio da homeostase emocional tem sido considerado como um mecanismo subjacente aos transtornos de ansiedade e humor. Em fêmeas, as alterações na secreção hormonal durante as diferentes fases do ciclo estral podem ser a base das alterações na reatividade emocional a eventos estressantes. Estudos comportamentais sobre diferenças sexuais no processamento das emoções mostram resultados conflitantes em fêmeas devido às dificuldades na seleção dos melhores modelos animais para testar as diferenças associadas ao ciclo estral. Uma vez que os testes comportamentais foram desenvolvidos em animais do sexo masculino, eles podem não ser apropriados para fêmeas. O presente estudo foi desenvolvido para contribuir nessa linha de pesquisa usando diferentes modelos de animais de medo incondicionado e condicionado, considerando as diferentes fases do ciclo estral das ratas. Comparou-se o desempenho de machos e fêmeas nas quatro fases do ciclo estral em dois testes de medo incondicionado: o switch-off, em que ratos cruzam uma caixa vai-e-vem para desligar uma luz aversiva, e o registro de vocalizações ultrassônicas (VUSs) a 22 kHz emitidos por animais sob o estresse agudo de restrição. Nos testes de medo condicionado, registrou-se o sobressalto potencializado pelo medo e a resposta decongelamento a um contexto aversivo. Em ambos os testes de medo condicionado, a reatividade emocional não se mostrou diferente entre os sexos. No entanto, no que diz respeito ao medo incondicionado, ratas em diestro tardio apresentaram maior reatividade emocional em desligar a luz intensa e maior emissão de VUSs em resposta à restrição em relação a outras fases do ciclo. Estes achados sugerem que o perfil hormonal durante a fase do diestro 2 pode aumentar a reatividade emocional de ratas frente a estímulos inatos, porém não àqueles aprendidos.<br>Dysfunctional emotional regulation has been implicated as a potential mechanism underlying anxiety and mood disorders. Changes in hormonal secretion during the different phases of the estrous cycle may underlie changes in emotional reactivity to stressful events in female animals. Previous behavioral studies of sex differences in emotion processing in females have yielded conflicting results. This may be due to the range of different behavioral tests used and difficulties in selecting the best animal models to test for estrous cycle-linked differences in responsiveness. Furthermore, the commonly used behavioral tests were developed in male animals and it may not be appropriate to translate directly the protocols from males to females. In the present study we have attempted to address these problems by using different animal models of anxiety based on tests for unconditioned or conditioned fear. We compared the performance of male rats and female rats at four stages of the estrous cycle defined by differences in vaginal cytology. To test for unconditioned fear, we used two tests: a light switch- off test, in which rats escape to the other compartment of a shuttle-box to turn off an aversive light and recordings of 22 kHz ultrasound vocalizations (USVs) during acute restraint stress. For the conditioned fear paradigm, we used fear potentiated startle in an aversive context and conditioned freezing using an aversive context as the conditioned stimulus. In both tests of conditioned fear there were no gender or estrous cycle-linked differences in emotional reactivity. However, with respect to unconditioned fear, female rats in late diestrus showed greater emotional reactivity expressed as switch-off responses to a light environment and USVs in response to restraint compared to other phases of the cycle. These findings suggest that the hormonal profile during the late diestrous phase may predispose to up-regulated emotional reactivity in rats facing emotional challenges to unconditioned, but not conditioned fear- inducing stimuli.
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Burns, Melissa Leah. "Effects of conditioned, unconditioned, and contextual stimuli on the direction of conditioned responding /." Digital version accessible at:, 1999. http://wwwlib.umi.com/cr/utexas/main.

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Vargo, Kristina K. "An Evaluation of Resistance to Change with Unconditioned and Conditioned Reinforcers." OpenSIUC, 2013. https://opensiuc.lib.siu.edu/dissertations/746.

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Several variables have been shown to influence resistance to change including rate, magnitude, and delay to reinforcement (Nevin, 1974). One variable that has not been studied with humans concerns the evaluation of resistance to change with unconditioned and conditioned reinforcers. In Experiment 1 (Resistance to Extinction Assessment), 5 participants' behaviors were reinforced during a baseline phase on a mult VI 30 s VI 30 s schedule with either a conditioned (i.e., token) or unconditioned reinforcer (i.e., food). Following equal reinforcement rates across components, extinction was introduced as a disruptor. All participants showed greater resistance to extinction in the component associated with conditioned reinforcers than unconditioned reinforcers. In Experiment 2 (Varied Distractors Assessment), 4 participants experienced a baseline phase the same as Experiment 1 (i.e., mult VI 30 s VI 30 s). Each participant was then exposed to prefeeding and distraction as disruptors in separate analyses. Results showed that behaviors were more resistant to distraction with conditioned than unconditioned reinforcers, similar to Experiment 1. However, when prefeeding disrupted responding, greater resistance to change was observed with unconditioned reinforcers than conditioned reinforcers. Implications of the results are discussed.
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Lee, Jennifer Elizabeth. "Comparison of Auditory Thresholds Obtained with a Conditioned and an Unconditioned Response." University of Toledo / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1325738685.

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Davison, Ian. "The effects of temporal relationships on the associability of both conditioned and unconditioned stimuli." Thesis, University of St Andrews, 1988. http://hdl.handle.net/10023/15083.

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Several models of animal associative learning are described. The evidence for the concept of associability is reviewed. The review contains a detailed account of blocking, including the Mackintosh, Bygrave and Picton (1977) experiment. It is shown that the two major associability models need to be modified, mathematically, to simulate the results of this experiment. A general, simple framework for investigating putative associability changes is suggested. A review of stimulus pre-exposure effects is put into this framework, and indicates a suitable direction for research. The experiments looked for associability changes of both conditioned and unconditioned stimuli. Sometimes the stimulus was a predictor of subsequent events; if not, it was predicted by another stimulus. A variety of procedures was employed. Experiments 1, 2, and 3 tried to replicate and extend previous work with a conditioned stimulus predicting subsequent events, but they were unsuccessful. Experiments 4, 5, 6, 7, and 8 investigated whether conditioned and unconditioned stimuli would change in associability when they were well predicted. Unfortunately, the data were difficult to interpret. An appetitive-aversive transfer paradigm was used in Experiments 9, 10, and 11; there was some evidence that a tone could change in associability, both when it was acting as a predictor, and when it was being predicted. Alternative Interpretations were also discussed. In Experiments 12 and 13, a shock was used to predict the occurrence of food; and there was no evidence that the associability of the shock could be increased in this way.
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Kim, Jee Hyun Psychology Faculty of Science UNSW. "Extinction of conditioned fear in the developing rat." Publisher:University of New South Wales. Psychology, 2008. http://handle.unsw.edu.au/1959.4/41106.

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The present thesis examined extinction of conditioned fear in the developing rat. In the adult rat, the hippocampus is thought to be important for the context-specificity of extinction. Because the hippocampus is a late-maturing structure, it was hypothesised that context-modulation of extinction may be different across development. The first series of experiments investigated reinstatement of extinguished fear in the developing rat (Chapter 2). The results showed that P24 rats exhibited context-specific reinstatement. On the other hand, P17 rats did not exhibit reinstatement of extinguished fear following a US reminder treatment. The failure to see reinstatement in P17 rats was not due to the reminder treatment being ineffective in these rats because the same treatment alleviated spontaneous forgetting in rat this age. The second series of experiments then examined the renewal effect and GABAergic involvement in extinction in P24 and P17 rats (Chapter 3). It was observed that P24 rats displayed renewal whereas P17 rats did not. Also, pre-test injection of FG7142 recovered extinguished fear in P24 rats but not in P17 rats, even across a range of doses. This failure to see any FG7142 effect on extinction in P17 rats was not due to the lack of responsiveness to this drug in these rats because FG7142 was found to be effective in alleviating spontaneous forgetting in rats this age. The third series of experiments then examined the effect of temporary inactivation of the amygdala on extinction and re-extinction in the developing rat (Chapter 4). It was observed that extinction retention is impaired in both P24 and P17 rats if the amygdala is inactivated during extinction training. Interestingly, when a CS that had been previously extinguished and then re-trained was re-extinguished, re-extinction was amygdala-independent if initial extinction occurred at 24 days of age but amygdala-dependent if initial extinction occurred at 17 days of age. That is, amygdala involvement in re-extinction was dissociated across development. Taken together, these experiments provide strong evidence for fundamental differences in mechanisms underlying fear extinction across development. The implications of the findings were discussed in light of the theoretical and neural models of extinction.
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Duke, Marcus Alan. "The effects of kappa opioid and dopamine agonists on unconditioned behaviors and fos immunoreactivity in preweanling and adult rats." CSUSB ScholarWorks, 1996. https://scholarworks.lib.csusb.edu/etd-project/1209.

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Books on the topic "Unconditioned and Conditioned Fear"

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Moskowich, Isabel, Gonzalo Camiña Rioboo, Inés Lareo, and Begoña Crespo, eds. 'The Conditioned and the Unconditioned'. John Benjamins Publishing Company, 2016. http://dx.doi.org/10.1075/z.198.

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Moskowich, Isabel. The conditioned and the unconditioned: Late modern English texts on Philosophy : edited by Isabel Moskowich ; Begoña Crespo, University of A Coruña. John Benjamins Publishing Company, 2016.

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Anderson, Ian G. Effects of instructions on electrodermal conditioned responses to "fear relevant" and "fear irrelevant" facial expressions: The relevance of preparedness to social phobias. [University of Surrey], 1987.

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Richman, Lesley M. Diet selection by conditioned and unconditioned goats in the sagebrush steppe of Eastern Oregon. 1993.

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Rodriguez-Romaguera, Jose, and Gregory J. Quirk. Extinction of Conditioned Fear and Avoidance: Relevance for OCD. Edited by Christopher Pittenger. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780190228163.003.0030.

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The compulsions seen in obsessive-compulsive disorder (OCD) often reflect a state of elevated fear and anxiety; ritualistic behaviors and/or avoidance may arise as a strategy to manage this anxiety. Treatment for OCD can include exposure-based therapies that attempt to extinguish compulsions. Exposure with response prevention(ERP) is an effective therapy, but approximately 40% of patients fail ERP or drop out. This chapter reviews the role of the medial prefrontal and orbitofrontal cortices in the extinction of conditioned fear and avoidance, in both rodents and humans. Special emphasize is given to how the rodent literature can provide new insights into the pathophysiology and treatment of OCD.
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Tasan, Ramon, and Nicolas Singewald. Animal Models and Assays Probing Anxiety Related Behaviors and Neural Circuits. Edited by Dennis S. Charney, Eric J. Nestler, Pamela Sklar, and Joseph D. Buxbaum. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780190681425.003.0035.

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Anxiety tests and models in rodents are useful tools to reveal neurochemical, cellular, and molecular underpinnings of normal and pathological anxiety-related behaviors, as well as novel treatment targets. While anxiety models are generated by various approaches such as selective breeding, anxiety tests most commonly involve unconditioned approach avoidance tasks and conditioned learning paradigms, both characterized by inherent advantages and limitations, in particular their predictive value for specific anxiety disorders. To further improve the validity and translatability of preclinical anxiety testing, it is promising that some anxiety-relevant endophenotypes have now been investigated using similar tests in rodents and humans and that the involved neural pathways and mechanisms overlap considerably in both species.
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Pineles, Suzanne L., and Scott P. Orr. The Psychophysiology of PTSD. Edited by Charles B. Nemeroff and Charles R. Marmar. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780190259440.003.0022.

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This chapter provides an overview of post-traumatic stress disorder (PTSD)-related psychophysiological research. Specific foci include psychophysiological reactivity to trauma-related stimuli and loud tones, conditioned fear acquisition and extinction, fear memory reconsolidation blockade, and the potential usefulness of psychophysiological measures in predicting PTSD development, maintenance, and treatment efficacy. A detailed discussion is provided on the contribution of reduced parasympathetic tone and increased sympathetic activity to the heightened psychophysiological reactivity associated with PTSD. Reduced parasympathetic tone may increase the risk of cardiovascular disease. Recent technological advances in physiological recording are also described.
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Gorman, Jack M. Is There a Science of Psychotherapy? Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780190850128.003.0008.

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Traditionally, psychotherapists have been reluctant to embrace neuroscience, incorrectly believing that it is solely devoted to finding more drugs for psychiatric illnesses. By thinking of psychotherapy as a type of life experience, however, we see that many aspects of neurobiology are relevant to psychotherapy and strengthen our understanding of how psychotherapy works. One example is studies showing that the same brain pathways involved in the acquisition and extinction of conditioned fear in laboratory animals and in anxiety disorders in humans are also affected by cognitive behavioral psychotherapy. Another example is the similarity of the ability to permanently abolish fear memory by blocking its reconsolidation and the reframing of a previously unconscious memory during psychoanalytic psychotherapy. A neuroscience of psychotherapy is certainly conceivable.
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Epstein, Joshua M. Mathematical Model. Princeton University Press, 2017. http://dx.doi.org/10.23943/princeton/9780691158884.003.0002.

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This part of the book describes explicit mathematical models for the affective, cognitive, and social components of Agent_Zero. It first considers some underlying neuroscience of fear and the role of the amygdala before turning to Rescorla–Wagner equations of conditioning. In particular, it explains how the fear circuit can be activated and how fear conditioning can occur unconsciously. It then reviews some standard nomenclature adopted by Ivan Pavlov in his study, Conditioned Reflexes: An Investigation of the Physiological Activity of the Cerebral Cortex, with emphasis on David Hume's “association of ideas,” the theory of conditioning, and the Rescorla–Wagner model. After examining “the passions,” the discussion focuses on reason, Agent_Zero's cognitive component, and the model's social component. The central case is that the agent initiates the group's behavior despite starting with the lowest disposition, with no initial emotional inclination, no evidence, the same threshold as all others, and no orders from above.
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Greenblatt, Stephen. Utopian Pleasure. Edited by James Simpson and Brian Cummings. Oxford University Press, 2015. http://dx.doi.org/10.1093/oxfordhb/9780199212484.013.0017.

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Lucretius’s didactic masterpieceDe rerum naturaadvances propositions, drawn from Epicurus, which the Renaissance book-hunter Poggio Bracciolini and his contemporaries found difficult to absorb. Epicurus’s convictions included an insistence on the superiority of reason over faith, a steadfast refusal of pious fear, a concomitant refusal to believe in afterlife, a belief in the mortality of the soul, a rejection of religion, and an advocacy of the pursuit of pleasure. To many orthodox Christians such arguments were the very definition of atheism. This article examines three responses toDe rerum natura: “The Renunciation of Youthful Indiscretion” by Marsilio Ficino, “The Divorce Settlement” by Poggio Bracciolini, and “Dialogical Disavowal” by Lorenzo Valla. It also considers how the link between humanism, wealth, and the exercise of power in England conditioned the most remarkable Renaissance English response to Lucretius and to everything he brought back into circulation. Finally, it analyzes Thomas More’sUtopia, its theory of the nature of pleasure, and its treatment of Epicureanism and the afterlife.
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Book chapters on the topic "Unconditioned and Conditioned Fear"

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Hoyer, Daniel, Eric P. Zorrilla, Pietro Cottone, et al. "Conditioned Fear." In Encyclopedia of Psychopharmacology. Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-540-68706-1_1618.

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Welsh, J. P., and J. A. Harvey. "Modulation of Conditioned and Unconditioned Reflexes." In The Olivocerebellar System in Motor Control. Springer Berlin Heidelberg, 1989. http://dx.doi.org/10.1007/978-3-642-73920-0_35.

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Moskowich, Isabel. "Philosophers and scientists from the Modern Age." In 'The Conditioned and the Unconditioned'. John Benjamins Publishing Company, 2016. http://dx.doi.org/10.1075/z.198.01mos.

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Crespo, Begoña. "Genre categorisation in CEPhiT." In 'The Conditioned and the Unconditioned'. John Benjamins Publishing Company, 2016. http://dx.doi.org/10.1075/z.198.02cre.

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Camiña Rioboo, Gonzalo, and Inés Lareo. "Editorial policy in the Corpus of English Philosophy Texts." In 'The Conditioned and the Unconditioned'. John Benjamins Publishing Company, 2016. http://dx.doi.org/10.1075/z.198.03cam.

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Hardie, Andrew. "Infrastructure for analysis of the CEPhiT corpus." In 'The Conditioned and the Unconditioned'. John Benjamins Publishing Company, 2016. http://dx.doi.org/10.1075/z.198.04har.

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Dossena, Marina. "On the shoulders of giants." In 'The Conditioned and the Unconditioned'. John Benjamins Publishing Company, 2016. http://dx.doi.org/10.1075/z.198.05dos.

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Monaco, Leida Maria. "Abstractness as diachronic variation in CEPhiT." In 'The Conditioned and the Unconditioned'. John Benjamins Publishing Company, 2016. http://dx.doi.org/10.1075/z.198.06mon.

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Seoane, Elena. "Authorial presence in late Modern English philosophical writing." In 'The Conditioned and the Unconditioned'. John Benjamins Publishing Company, 2016. http://dx.doi.org/10.1075/z.198.07seo.

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Alonso Almeida, Francisco, and Inés Lareo. "The status of seem in the nineteenth-century Corpus of English Philosophy Texts (CEPhiT)." In 'The Conditioned and the Unconditioned'. John Benjamins Publishing Company, 2016. http://dx.doi.org/10.1075/z.198.08alo.

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Conference papers on the topic "Unconditioned and Conditioned Fear"

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Li, Guoshi, Stacy Cheng, Frank Ko, Scott L. Raunch, Gregory Quirk, and Satish S. Nair. "Computational Modeling of Lateral Amygdala Neurons During Acquisition and Extinction of Conditioned Fear, Using Hebbian Learning." In ASME 2006 International Mechanical Engineering Congress and Exposition. ASMEDC, 2006. http://dx.doi.org/10.1115/imece2006-15078.

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The amygdaloid complex located within the medial temporal lobe plays an important role in the acquisition and expression of learned fear associations (Quirk et al. 2003) and contains three main components: the lateral nucleus (LA), the basal nucleus (BLA), and the central nucleus (CE) (Faber and Sah, 2002). The lateral nucleus of the amygdala (LA) is widely accepted to be a key site of plastic synaptic events that contributes to fear learning (Pare, Quirk, LeDoux, 2004). There are two main types of neurons within the LA and the BLA: principal pyramidal-like cells which form projection neurons and are glutamatergic and local circuit GABAergic interneurons (Faber and Sah, 2002). In auditory fear conditioning, convergence of tone [conditioned stimulus (CS)] and foot-shock [unconditioned stimulus (US)] inputs potentiates the synaptic transmission containing CS information from the thalamus and cortex to LA, which leads to larger responses in LA in the presentation of subsequent tones only. The increasing LA responses disinhibit the CE neurons via the intercalated (ITC) cells, eliciting fear responses via excessive projections to brain stem and hypothalamic sites (Pare, Quirk, LeDoux, 2004). As a result, rats learn to freeze to a tone that predicts a foot-shock. Once acquired, conditioned fear associations are not always expressed and repeated presentation of the tone CS in the absence of US causes conditioned fear responses to rapidly diminish, a phenomenon termed fear extinction (Quirk et al. 2003). Extinction does not erase the CS-US association, instead it forms a new memory that inhibits conditioned response (Quirk et al. 2003)
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"Effect of Conditioned Stimulus Generalization on Regression of Fear Memory Fading." In 2017 3rd International Conference on Environment, Biology, Medicine and Computer Applications. Francis Academic Press, 2017. http://dx.doi.org/10.25236/icebmca.2017.05.

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Li, Guoshi, Gregory J. Quirk, and Satish S. Nair. "Modeling Acquisition and Extinction of Conditioned Fear in LA Neurons using Learning Algorithm." In 2007 American Control Conference. IEEE, 2007. http://dx.doi.org/10.1109/acc.2007.4283135.

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Pendyam, Sandeep, Dongbeom Kim, Gregory J. Quirk, and Satish S. Nair. "Acquisition of Fear and Extinction in Lateral Amygdala: A Modeling Study." In ASME 2010 Dynamic Systems and Control Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/dscc2010-4218.

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The lateral nucleus of amygdala (LA) is known to be a critical storage site for conditioned fear memory. Synaptic plasticity at auditory inputs to the dorsal LA (LAd) is critical for the formation and storage of auditory fear memories. Recent evidence suggests that two different cell populations (transient- and long-term plastic cells) are present in LAd and are responsible for fear learning. However, the mechanisms involved in the formation and storage of fear are not well understood. As an extension of previous work, a biologically realistic computational model of the LAd circuitry is developed to investigate these mechanisms. The network model consists of 52 LA pyramidal neurons and 13 interneurons. Auditory and somatosensory information reaches LA from both thalamic and cortical inputs. The model replicated the tone responses observed in the two LAd cell populations during conditioning and extinction. The model provides insights into the role of thalamic and cortical inputs in fear memory formation and storage.
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Gordon, John R., Richard L. Minichan, and James A. Mullner. "An Analytical Technique to Determine the Potential for Moisture Accumulation in Deactivated Structures." In ASME 2004 Heat Transfer/Fluids Engineering Summer Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/ht-fed2004-56895.

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This paper describes an analytical technique developed to predict an order of magnitude volume of moisture accumulation in massive structures after deactivation. This work was done to support deactivation of a Department of Energy nuclear materials processing facility. The structure is a four-story, concrete building with a rectangular footprint that is approximately 250m long by 37m wide by 22m high. Its walls are 1.2m thick. The building will be supplied with unconditioned ventilation air after deactivation. The objective of the work was to provide a cost effective engineering evaluation to determine if the un-conditioned ventilation air would result in condensate accumulating inside the building under study. The analysis described is a simple representation of a complex problem. The modeling method is discussed in sufficient detail to allow its application to the study of similar structures.
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Owuor, Peter, Alfred Tcherbi-Narteh, Mahesh Hosur, and Shaik Jeelani. "Durability Studies of Hybrid Composite of E-Glass/Carbon Fibers in Different Solvents for Bridge Deck Panel Application." In ASME 2014 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/imece2014-36175.

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Objective An experimental study was carried out to investigate the solvent uptake in E-glass/Carbon Fiber composites with two types of epoxy systems: SC-15 and 635 epoxy resins in water, saltwater and antifreeze. These resins were infused into carbon, E glass and a hybrid of carbon and E-glass fabrics. Unconditioned samples with 635 epoxy resin system showed better flexural properties in case of both carbon fiber and hybrid composites but poor response when used as a matrix for E-glass fibers compared to SC-15 epoxy resin. Flexural properties for conditioned samples were determined after an immersion period of 8 weeks at room temperature and results showed that the 635 epoxy resin has a poor retention of flexural properties compared to SC-15 epoxy resin with highest degradation recorded for samples fabricated using E-glass fabrics. Moisture absorption curves did not follow the Fick’s law of diffusion except for first week of immersion. Lowest solvent uptake was recorded in antifreeze while highest was recorded in saltwater. Low operation temperature was exhibited by 635 epoxy resin with lower values of glass transition temperature compared to SC-15 epoxy resin. Storage modulus and glass transition temperatures determined from dynamic mechanical analysis (DMA) showed that composites with 635 epoxy resin system had better storage modulus while those with SC-15 had higher glass transition temperatures. Highest degradation in storage modulus was seen in E-glass-635 epoxy samples when conditioned with salt water while the maximum reduction in the glass transition temperature was seen for E-glass-635 epoxy samples conditioned with water.
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Li, Guoqiang, Su-Seng Pang, Jack E. Helms, and Samuel I. Ibekwe. "Durability of FRP Strengthened RC Beams Subjected to Hygrothermal and Aging Attacks." In ASME 2001 Engineering Technology Conference on Energy. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/etce2001-17023.

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Abstract The past decade has witnessed an ever increasing interest in strengthening, repairing, retrofitting, and upgrading of deteriorated concrete structures using fiber reinforced plastics (FRP). Enhanced load carrying capacity by FRP strengthening has been observed by a large number of researchers through experiments at ambient environments. In a harsh environment, however, FRP will degrade. This may result in structural degradation of FRP strengthened concrete members. The possible structural degradation has become a major obstacle for the wide-spread acceptance of this new strengthening technique. In the present study, boiling water and ultraviolet (UV) radiation are used to study the structural degradation of concrete beams strengthened with GRFP and CFRP fabrics. A total of eighteen 170 × 7.62 × 15.2 cm steel reinforced concrete (RC) beams are prepared as control specimens, conditioned specimens, and unconditioned specimens. The test results show that environmental attacks have a considerable effect on the structural degradation of FRP strengthened concrete beams. 57% ∼ 76% of the strengthening efficiency of FRP is lost after conditioning.
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Lin, Chuen-Sen, Terry Lee, and Bao-Ping Jia. "A Proposed Categorization Method and Category Domain Inequality Development Procedure for Ground Joints of Five Bar Linkages." In ASME 1998 Design Engineering Technical Conferences. American Society of Mechanical Engineers, 1998. http://dx.doi.org/10.1115/detc98/mech-5931.

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Abstract This paper presents a method for the development of sets of symbolic inequalities in terms of link lengths for the prediction of the rotation capabilities of ground joints of single-loop five-bar linkages. The inequalities are obtained from the combination of the loop equation of a five-bar linkage and its derivatives and the application of simple logic operations. The rotation capabilities of ground joints are divided into three categories: the incomplete-rotation ground joints, the conditioned complete-rotation ground joints, and the unconditioned complete-rotation ground joints. The derived sets of inequalities define the domain, in a five-dimension space of the five link lengths, for each of the rotation categories. In this paper, the definition of each category is clearly described and the derivations of sets of inequalities are explained in details. A computer program was constructed to examine the completeness and correctness of the categorization method and to analyze the given five-bar linkages to determine the appropriate categories for their ground joints.
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Adams, J. J., J. A. Jarboe, M. D. Feit та R. P. Hackel. "Comparison between S/1 and R/1 tests and damage density vs. fluence (ρ(Φ)) results for unconditioned and sub-nanosecond laser-conditioned KD 2 PO 4 crystals". У Boulder Damage Symposium XXXIX: Annual Symposium on Optical Materials for High Power Lasers, редактори Gregory J. Exarhos, Arthur H. Guenther, Keith L. Lewis, Detlev Ristau, M. J. Soileau та Christopher J. Stolz. SPIE, 2007. http://dx.doi.org/10.1117/12.752961.

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Beck, Joseph R., Daniel F. Walczyk, Casey J. Hoffman, and Steve J. Buelte. "Ultrasonic Bonding of Membrane Electrode Assemblies for Low Temperature PEM Fuel Cells." In ASME 2012 10th International Conference on Fuel Cell Science, Engineering and Technology collocated with the ASME 2012 6th International Conference on Energy Sustainability. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/fuelcell2012-91308.

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Ultrasonic bonding of low temperature PEM membrane electrode assemblies has shown to cut the cycle time and energy input of manufacturing by over an order of magnitude each as compared to the industry standard of thermal pressing. Ultrasonic bonding uses high-frequency mechanical oscillations to convert electrical energy into heat energy which bonds the membrane electrode assembly components. This reduction in manufacturing resource requirement and time helps make fuel cell energy more economical as an alternative electrical power source. This paper will discuss ultrasonic and thermal bonding for low temperature Nafion fuel cells with 10 cm2 active area including process optimization and the effects of electrode type and membrane conditioning on ultrasonically bonded MEA performance. A design set of experiments was created for both ultrasonic bonding and thermal pressing process optimization using commercially available electrodes and conditioned Nafion 115 membrane. Analysis of Variance suggests that neither energy nor pressure have a statistically significant effect on the performance on ultrasonically bonded MEAs. For thermally pressed MEAs, temperature was found to have a significant effect on performance while pressure was not. Neither manufacturing technique found interaction effects to be statistically significant. Three different electrode compositions were tested on both ultrasonic and thermal MEA bonding methods. Electrodes investigated include two that were custom made in-house with catalyst loadings of 0.16 and 0.33 mg Pt/cm2, and one commercial electrode with 0.5 mg Pt/cm2. The lower loaded custom electrode had greater performance than the commercial electrode, which had higher platinum loading, indicating electrode architecture is an important factor in the performance of ultrasonically bonded MEAs. Membrane electrode assemblies made using Nafion membranes that were pretreated with a conditioning process showed decreased performance compared to MEAs ultrasonically bonded from dry, unconditioned membrane in short-term testing. MEAs thermally pressed with the custom made electrodes performed better with conditioned membranes while the commercial electrodes showed decreased performance with conditioning. Current electrodes have been optimized for thermal pressing as demonstrated by the two commercial electrodes having the largest performance decreases between thermally and ultrasonically manufactured MEAs. Future work includes intelligently designing an electrode for optimizing the ultrasonic bonding process for low temperature fuel cells to increase the performance of this manufacturing technique.
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Reports on the topic "Unconditioned and Conditioned Fear"

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Kaste, Robert P. The Effect of an Unconditioned Barrel on Temperature Conditioned 5.56mm Cartridges. Defense Technical Information Center, 2009. http://dx.doi.org/10.21236/ada502629.

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Norrholm, Seth D. Conditioned Fear Extinction and Generalization in Posttraumatic Stress Disorder. Defense Technical Information Center, 2011. http://dx.doi.org/10.21236/ada555145.

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Vettori, Robert. Estimates of thermal conductivity for unconditioned and conditioned materials used in fire fighters' protective clothing. National Institute of Standards and Technology, 2005. http://dx.doi.org/10.6028/nist.ir.7279.

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Norrholm, Seth D., Erica Duncan, Kerry Ressler, and Joseph Cubells. Conditioned Fear Extinction and Generalization in Post-Traumatic Stress Disorder. Defense Technical Information Center, 2012. http://dx.doi.org/10.21236/ada579112.

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