Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 20 for “"Conditioned Fear"”.
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The molecular substrates of second-order conditioned fear in the basolateral amygdala
Rodents learn to fear a stimulus (e.g., a light) that signals the imminent arrival of an innate source of danger (typically an aversive foot shock). They also learn to fear a stimulus (e.g., a noise) that signals a learned source of danger (e.g., the already conditioned fear-eliciting light). …
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Conditioned Fear as a Function of the Inter-Stimulus and Probe-Stimulus Intervals
Made available in DSpace on 2014-12-08T23:01:13Z (GMT). No. of bitstreams: 1 6503603.pdf: 2452008 bytes, checksum: 30c09a3479da3dd0142f4a7a108b2ac2 (MD5) Previous issue date: 1964
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Suppressing What Hurts: The Role of Prefrontal-Thalamic Pathways in Inhibitory Control of Intrusive Thoughts and Conditioned Fear
… in mediating such top-down control. Further, fear extinction which forms the basis of exposure therapy has been hypothesized to employ retrieval stopping processes. If this holds true, humans may be capable of extinguishing fear by suppressing its retrieval. In rodents, the NRe has been widely …
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EFFECTS OF ACUTE THC ADMINISTRATION ON EXTINCTION OF CONDITIONED FEAR RESPONSES IN HUMANS: A FUNCTIONAL ANALYSIS OF HIGH DENSITY EEG
… (THC) administration on extinction of conditioned fear responses. Fear conditioning was initiated using a differential classical conditioning paradigm that paired an aversive unconditioned stimulus (shock) with a signaling stimulus (CS+), whereas another stimulus served as a safety …
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A psychological analysis of the effects of memory retrieval prior to extinction on the reacquisition of a conditioned fear association
The successful reduction of fear is the aim of clinicians treating people with anxiety disorders such as post-traumatic stress disorder or phobias. Existing treatments for these conditions, however, require many treatment sessions and are prone to relapse. A new technique, first demonstrated in …
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Infusion of oxytocin into the basolateral amygdala facilitates, whereas infusion into the central nucleus impairs extinction of context conditioned fear responses in rats
… neurons (Knobloch et al., 2012) reduced conditioned freezing responses. In contrast, intracerebroventricular (i.c.v.) administration of OT increased conditioned freezing responses (Toth, Neumann, & Slattery, 2012). The route of administration may account for these differences in fear …
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Dissecting the Functional Heterogeneity of Serotonergic Systems That Regulate Fear and Panic
… a flight or escape response) or condi-tioned fear behaviors is still elusive. Therefore, utilizing circuit-based gain- and loss-of-function approaches to selectively manipulate amygdala- and PeFR-projecting sero-tonergic systems, we hypothesize that specific serotonergic networks projecting to …
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Effects of alley brightness cue manipulation preceding shock on self-punitive responding in the rat
… have shown that the strength of classically conditioned fear varies inversely with the length of the CS-UCS interval (McAllister & McAllister, 1971). If fear conditioning is important in the vicious-circle (VC) phenomenon (Brown, 1969; Melvin, 1971; Mowrer, 1947), then the interstimulus …
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Group II Metabolic Glutamate Receptors in the Basal Amygdala Regulate Sleep and Fear-Induced Alterations in Sleep
… direct connections with the CNA, is involved in conditioned fear and fear extinction. However, the potential role of the BA in the regulation of sleep has received little attention. In this study, we investigated the role of mGlu II receptors in sleep and stress-induced alterations in sleep.</p> …
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Antidepressant-Like Effects of Ketamine on Fear Conditioning and Extinction
… emotional events can be studied in animals using fear conditioning and extinction paradigms. Fear conditioning trains an animal to associate a neutral cue with an emotionally aversive experience, while extinction learning challenges this association by forming a new memory that identifies the cue …
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5,7-dihydroxytryptamine lesions of the rat amygdala increase learned fear behavior.
… of the amygdala (LA) plays a key role in learned fear and anxiety, while dysfunctional LA circuitry is implicated in fear and anxiety psychopathologies. The LA is under inhibitory modulation and prone to hyperexcitation with inhibitory release. This hyperexcitation can result in enhanced fear and …
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Differential contributions of subregions of the dorsal anterior cingulate cortex to negative emotion in the common marmoset
… distinct components of negative emotion, such as conditioned fear and anxiety. The findings suggest that the rostral dACC and the caudal dACC do indeed have distinct contributions to the expression of negative emotion and the regulation of anxiety, respectively. Furthermore, an assessment of the …
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A move towards studying both pavlovian & instrumental contributions to conditioning abnormalities in the anxiety disorders
Fear-conditioning experiments in clinical anxiety have focused almost exclusively on passive- emotional, Pavlovian conditioning, rather than active-behavioral, instrumental conditioning. Paradigms capable of eliciting both Pavlovian and instrumental conditioning are thus needed to experimentally …
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Dopaminergic modulation of basolateral amygdala for fear extinction
The extinction of conditioned fear responses is crucial for adaptive behavior, and its impairment is a hallmark of anxiety disorders such as post-traumatic stress disorder. During fear extinction learning, a new memory is formed in basolateral amygdala (BLA) reward neurons, which inhibits the BLA …
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Endocannabinoid Modulation of Spatial Memory in Aversively and Appetitively Motivated Barnes Maze Tasks
… learning in aversive conditioning (i.e., conditioned fear and Morris water maze) paradigms, but not in operant procedures in which food reinforcement is earned. It is difficult to discern whether the differential effects caused by CB1 receptor disruption on extinction result from the …
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Serotonin and Threat: from Gene to Behaviour
Anxiety and fear are emotions provoked by threatening situations and shape adaptive behaviours, but excessive and uncontrollable anxiety and fear form core symptoms of anxiety disorders. High trait anxiety, an individual’s disposition to feel anxious, is associated with greater risk of developing …
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Examining the transfer of fear and avoidance response functions through real-world verbal relations.
… According to this process, the functions of conditioned stimuli (e.g., words) can emerge spontaneously for other stimuli in the language network (e.g., other words). Given this, it is not difficult to see how fear and avoidance can quickly become a clinical issue for verbally able humans once …
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Calcium-Stimulated Adenylyl Cyclases are Critical Modulators of Fear Learning and Experience-Dependent Plasticity
… cyclases: AC), AC1 and AC8, in modulating fear memory. Ca<super>2+</super>-stimulated AC activity couples neuronal activity and intracellular Ca<super>2+</super> increases to the production of cAMP, and therefore, can very tightly regulate signal transduction after learning; yet, the …
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ASSESSMENT OF NEUROTENSIN RECEPTOR AGONIST EFFECTS ON FEAR-POTENTIATED STARTLE
… in both male and female C57BL/J6 mice using the fear-potentiated startle (FPS) paradigm. Startle chambers were equipped with a shock-grid floor, fluorescent light, and an acoustic startle speaker. Conditioning took place between the light and floor shock, and test sessions measured startle to a …
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Evaluation of the Role of Astrocyte Glutamate Transport and of Synaptic NMDA Receptor Subtype Representation in the Pathogenesis of PTSD
… during situational trauma selectively inhibits fear extinction memory processes in the prefrontal cortex, but not of conditioned fear memory processes in the amygdala, due to differences between these brain regions in expression of NMDA receptor subtypes. The effect of GLT-1 manipulation was …