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Contextual fear

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https://www.readbyqxmd.com/read/28917978/sen1500-a-novel-oral-amyloid-%C3%AE-aggregation-inhibitor-attenuates-brain-pathology-in-a-mouse-model-of-alzheimer-s-disease
#1
D Brunner, S Flunkert, J Neddens, S Duller, D I C Scopes, J M Treherne, B Hutter-Paier
INTRODUCTION: Amyloid-β (Aβ) aggregation is thought to be a major pathogenic event underlying the neuropathology of Alzheimer's disease (AD). The development of new drugs inhibiting the Aβ aggregation process is, therefore, important. SEN1500, an orally bioavailable and CNS-penetrant Aβ aggregation inhibitor, has previously been shown to reduce spatial learning and memory deficits in an APP transgenic mouse model. To verify that the pharmacological properties of SEN1500 are not unique to this model, we investigated brain Aβ pathology, neuroinflammation, as well as memory in a different mouse model of AD expressing the human amyloid precursor protein with Swedish and London mutations (APPSL)...
September 13, 2017: Neuroscience Letters
https://www.readbyqxmd.com/read/28916748/%C3%AE-2-adrenoceptor-mediated-inhibition-in-the-central-amygdala-blocks-fear-conditioning
#2
N M Holmes, J W Crane, M Tang, J Fam, R F Westbrook, A J Delaney
The central amygdala is critical for the acquisition and expression of fear memories. This region receives a dense innervation from brainstem noradrenergic cell groups and has a high level of α2-adrenoceptor expression. Using whole-cell electrophysiological recordings from rat brain slices, we characterise the role of pre-synaptic α2-adrenoceptor in modulating discrete inhibitory and excitatory connections within both the lateral and medial division of the central amygdala. The selective α2-adrenoceptor agonist clonidine blocked the excitatory input from the pontine parabrachial neurons onto neurons of the lateral central amygdala...
September 15, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28916626/contextual-fear-conditioning-in-zebrafish
#3
Justin W Kenney, Ian C Scott, Sheena A Josselyn, Paul W Frankland
Zebrafish are a genetically tractable vertebrate that hold considerable promise for elucidating the molecular basis of behavior. Although numerous recent advances have been made in the ability to precisely manipulate the zebrafish genome, much less is known about many aspects of learning and memory in adult fish. Here, we describe the development of a contextual fear conditioning paradigm using an electric shock as the aversive stimulus. We find that contextual fear conditioning is modulated by shock intensity, prevented by an established amnestic agent (MK-801), lasts at least 14 d, and exhibits extinction...
October 2017: Learning & Memory
https://www.readbyqxmd.com/read/28916300/distinct-neuronal-populations-in-the-basolateral-and-central-amygdala-are-activated-with-acute-pain-conditioned-fear-and-fear-conditioned-analgesia
#4
Ryan K Butler, Sarah Ehling, Megan Barbar, Jess Thomas, Mary A Hughes, Charles E Smith, Vladimir M Pogorelov, Dipendra K Aryal, William C Wetsel, B Duncan X Lascelles
Fear-conditioned analgesia (FCA) is modulated by brain areas involved in the descending inhibitory pain pathway such as the basolateral (BLA) and central amygdala (CEA). The BLA contains Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) and parvalbumin (PV) neurons. CEA neurons are primarily inhibitory (GABAergic) that comprise enkephalin (ENK) interneurons and corticotropin-releasing factor (CRF) - neurons that project to the periaqueductal grey. The purpose of our experiment was to determine the pattern of activation of CaMKII/PV and ENK/CRF neurons following the expression of acute pain, conditioned fear, and FCA...
September 12, 2017: Neuroscience Letters
https://www.readbyqxmd.com/read/28902836/hippocampal-ltp-and-contextual-learning-require-surface-diffusion-of-ampa-receptors
#5
A C Penn, C L Zhang, F Georges, L Royer, C Breillat, E Hosy, J D Petersen, Y Humeau, D Choquet
Long-term potentiation (LTP) of excitatory synaptic transmission has long been considered a cellular correlate for learning and memory. Early LTP (less than 1 h) had initially been explained either by presynaptic increases in glutamate release or by direct modification of postsynaptic AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) receptor function. Compelling models have more recently proposed that synaptic potentiation can occur by the recruitment of additional postsynaptic AMPA receptors (AMPARs), sourced either from an intracellular reserve pool by exocytosis or from nearby extra-synaptic receptors pre-existing on the neuronal surface...
September 13, 2017: Nature
https://www.readbyqxmd.com/read/28900727/uhrf2-deletion-impairs-the-formation-of-hippocampus-dependent-memory-by-changing-the-structure-of-the-dentate-gyrus
#6
Xiao-Rong Chen, Shi-Cheng Sun, Shuai-Wen Teng, Liang Li, Yi-Fan Bie, Hui Yu, Da-Li Li, Zhe-Yu Chen, Yue Wang
Ubiquitin-like with PHD and ring finger domains 2 (Uhrf2) is distributed in many brain regions, including the cortex and hippocampus. Decreased Uhrf2 expression is involved in neurodegenerative disease. A recent study showed Uhrf2 deletion impaired spatial memory; however, the mechanism remains elusive. In our study, we determined that Uhrf2(+/-) and Uhrf2(-/-) mice had significant learning and memory deficiencies in contextual fear conditioning (CFC) and the novel place recognition test but not in the novel object recognition test...
September 12, 2017: Brain Structure & Function
https://www.readbyqxmd.com/read/28893073/challenges-faced-by-caregivers-of-children-on-antiretroviral-therapy-at-mutale-municipality-selected-healthcare-facilities-vhembe-district-limpopo-province
#7
Rhudzani V Mafune, Rachel T Lebese, Livhuwani H Nemathaga
BACKGROUND: Children depend solely on caregivers who can be either parents or guardians for drug administration to enhance adherence to antiretroviral treatment (ART), which might pose any number of challenges. PURPOSE: The purpose of this study was to explore and describe the challenges faced by caregivers of children on ART at Mutale Municipality, Vhembe District, Limpopo Province. RESEARCH DESIGN AND METHOD: The research design was qualitative, explorative, descriptive and contextual in nature...
August 28, 2017: Curationis
https://www.readbyqxmd.com/read/28888982/disrupting-nnos-psd-95-coupling-in-the-hippocampal-dentate-gyrus-promotes-extinction-memory-retrieval
#8
Jun Li, Zhou Han, Bo Cao, Cheng-Yun Cai, Yu-Hui Lin, Fei Li, Hai-Ying Wu, Lei Chang, Chun-Xia Luo, Dong-Ya Zhu
Granule cells in the dentate gyrus regenerate constantly in adult hippocampus and then integrate into neural circuits in the hippocampus thereby providing the neural basis for learning and memory. Promoting the neurogenesis in the hippocampus facilitates learning and memory such as spatial learning, object identification, and extinction learning. The interaction between neuronal nitric oxide synthase (nNOS) and postsynaptic density protein-95 (PSD-95) is reported to negatively regulate neurogenesis in brain, so we hypothesized that disrupting this interaction might facilitate the neurogenesis in the dentate gyrus (DG) and thus enhance the extinction memory retrieval of fear learning...
September 6, 2017: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/28888955/distinct-roles-of-neuronal-and-microglial-cb2-cannabinoid-receptors-in-the-mouse-hippocampus
#9
Yong Li, Jimok Kim
The effects of cannabinoids are primarily mediated by type-1 cannabinoid receptors in the brain and type-2 cannabinoid receptors (CB2Rs) in the peripheral immune system. However, recent evidence demonstrates that CB2Rs are also expressed in the brain and implicated in neuropsychiatric effects. Diverse types of cells in various regions in the brain express CB2Rs but the cellular loci of CB2Rs that induce specific behavioral effects have not been determined. To manipulate CB2R expression in specific types of cells in the dorsal hippocampus of adult mice, we used Cre-dependent overexpression and CRISPR-Cas9 genome editing techniques in combination with adeno-associated viruses and transgenic mice...
September 6, 2017: Neuroscience
https://www.readbyqxmd.com/read/28887641/interference-effects-of-transcranial-direct-current-stimulation-over-the-right-frontal-cortex-and-adrenergic-system-on-conditioned-fear
#10
Mohammad Nasehi, Reyhaneh Soltanpour, Mohaddeseh Ebrahimi-Ghiri, Shahram Zarrabian, Mohammad-Reza Zarrindast
RATIONALE: The effects of pharmacological interventions on fear memory have widely been studied, but there are very few studies about the effects of brain electrical stimulation on fear memory function. OBJECTIVE: Therefore, our aim was to determine whether anodal/cathodal transcranial direct current stimulation (tDCS) over the right frontal cortex would modify propranolol-induced contextual and auditory fear memory deficits, before or after training. METHODS: The adult NMRI male mice were randomly assigned into three groups: the sham group, the anodal tDCS group, and the cathodal tDCS group...
September 8, 2017: Psychopharmacology
https://www.readbyqxmd.com/read/28887561/enhancement-of-extinction-memory-by-pharmacological-and-behavioral-interventions-targeted-to-its-reactivation
#11
Josué Haubrich, Adriano Machado, Flávia Zacouteguy Boos, Ana P Crestani, Rodrigo O Sierra, Lucas de Oliveira Alvares, Jorge A Quillfeldt
Extinction is a process that involves new learning that inhibits the expression of previously acquired memories. Although temporarily effective, extinction does not erase an original fear association. Since the extinction trace tends to fade over time, the original memory can resurge. On the other hand, strengthening effects have been described in several reconsolidation studies using different behavioral and pharmacological manipulations. In order to know whether an extinction memory can be strengthened by reactivation-based interventions in the contextual fear conditioning task, we began by replicating the classic phenomenon of spontaneous recovery to show that brief reexposure sessions can prevent the decay of the extinction trace over time in a long-lasting way...
September 8, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28885933/a-qualitative-study-of-participation-in-cardiac-rehabilitation-programs-in-an-integrated-health-care-system
#12
Nathalie McIntosh, Gemmae M Fix, Kelly Allsup, Martin Charns, Sarah McDannold, Kenneth Manning, Daniel E Forman
INTRODUCTION: Despite strong incentives to use cardiac rehabilitation (CR), patient participation is low in the Veterans Health Administration (VHA). This is paradoxical given that VHA is an integrated health care system that offers a range of CR programs which should logically reduce barriers to access to CR participation. The purpose of this study was to better understand the contextual factors that influence patient participation in CR and how patients consider factors together when making decisions about CR participation...
September 2017: Military Medicine
https://www.readbyqxmd.com/read/28881795/rnase-alleviates-neurological-dysfunction-in-mice-undergoing-cardiac-arrest-and-cardiopulmonary-resuscitation
#13
Ye Ma, Chan Chen, Shu Zhang, Qiao Wang, Hai Chen, Yuanlin Dong, Zheng Zhang, Yan Li, Zhendong Niu, Tao Zhu, Hai Yu, Bin Liu
Cardiac arrest (CA) is one of the leading lethal factors. Despite cardiopulmonary resuscitation (CPR) procedure has been consecutively improved and lots of new strategies have been developed, neurological outcome of the patients experienced CPR is still disappointing. Ribonuclease (RNase) has been demonstrated to have neuroprotective effects in acute stroke and postoperative cognitive impairment, possibly through acting against endogenous RNA that released from damaged tissue. However, the role of RNase in post-cardiac arrest cerebral injury is unknown...
August 8, 2017: Oncotarget
https://www.readbyqxmd.com/read/28868118/effects-of-left-prefrontal-transcranial-direct-current-stimulation-on-the-acquisition-of-contextual-and-cued-fear-memory
#14
Shahsanam Abbasi, Mohammad Nasehi, Hamid Reza Soleimanpour Lichaei, Mohammad-Reza Zarrindast
OBJECTIVES: Behavioral and neuroimaging studies have shown that transcranial direct current stimulation, as a non-invasive neuromodulatory technique, beyond regional effects can modify functionally interconnected remote cortical and subcortical areas. In this study, we hypothesized that the induced changes in cortical excitability following the application of cathodal or anodal tDCS over the left frontal cortex as pre-training would affect functional connectivity in resting-state circuits of fear memory and consequently could improve or disturb the acquisition of fear memory...
June 2017: Iranian Journal of Basic Medical Sciences
https://www.readbyqxmd.com/read/28864239/network-oscillatory-activity-driven-by-context-memory-processing-is-differently-regulated-by-glutamatergic-and-cholinergic-neurotransmission
#15
Adam M P Miller, Brendan J Frick, David M Smith, Jelena Radulovic, Kevin A Corcoran
Memory retrieval requires coordinated intra- and inter-regional activity in networks of brain structures. Dysfunction of these networks and memory impairment are seen in many psychiatric disorders, but relatively little is known about how memory retrieval and memory failure are represented at the level of local and regional oscillatory activity. To address this question, we measured local field potentials (LFPs) from mice as they explored a novel context, retrieved memories for contextual fear conditioning, and after administration of two amnestic agents: the NMDA receptor antagonist MK-801 and muscarinic acetylcholine receptor antagonist scopolamine (SCOP)...
August 30, 2017: Neurobiology of Learning and Memory
https://www.readbyqxmd.com/read/28863004/dexamethasone-impairs-encoding-and-expression-of-aversive-conditioning-promoted-by-pentylenetetrazole
#16
Juliana Cavalli, Alexandre A Hoeller, Silvia Dal Bó, Leandro J Bertoglio, Thereza C M de Lima, Antonio P Carobrez
Behavioral and neuroendocrine responses following threatening situations promote the release of corticosterone, which is known to modulate trauma-related learning and memory process. However, it remains unknown whether the aversive learning generated by interoceptive fear conditioning is affected by glucocorticoid modulation. Therefore, the present study aimed to investigate the role of dexamethasone suppression in encoding and expression of pentylenetetrazole-induced olfactory fear conditioning (OFC) and in contextual second-order conditioning promoted by the conditioned odor...
August 31, 2017: Behavioural Pharmacology
https://www.readbyqxmd.com/read/28861709/a-nociceptive-stress-model-of-adolescent-physical-abuse-induces-contextual-fear-and-cingulate-nociceptive-neuroplasticities
#17
Brent A Vogt, Leslie J Vogt, Robert W Sikes
Adolescent physical abuse impairs emotional development and evokes cingulate pathologies, but its neuronal and circuit substrates are unknown. Conditioning adolescent rabbits with noxious colorectal distension for only 2 h over 3 weeks simulated the human child abuse in amplitude, frequency, and duration. Thermal withdrawal thresholds were unchanged suggesting that sensitized spinal mechanisms may not be operable. Unchanged weight, stools, colorectal histology, and no evidence of abdominal pain argue against tissue injury or irritable bowel syndrome...
August 31, 2017: Brain Structure & Function
https://www.readbyqxmd.com/read/28861501/palmitoylethanolamide-modulates-gpr55-receptor-signaling-in-the-ventral-hippocampus-to-regulate-mesolimbic-dopamine-activity-social-interaction-and-memory-processing
#18
Cecilia Kramar, Michael Loureiro, Justine Renard, Steven R Laviolette
Introduction: The GPR55 receptor has been identified as an atypical cannabinoid receptor and is implicated in various physiological processes. However, its functional role in the central nervous system is not currently understood. The presence of GPR55 receptor in neural regions such as the ventral hippocampus (vHipp), which is critical for cognition, recognition memory, and affective processing, led us to hypothesize that intra-vHipp GPR55 transmission may modulate mesolimbic activity states and related behavioral phenomena...
2017: Cannabis and Cannabinoid Research
https://www.readbyqxmd.com/read/28857753/does-individual-stigma-predict-mental-health-funding-attitudes-toward-an-understanding-of-resource-allocation-and-social-climate
#19
Joseph S DeLuca, Timothy W Clement, Philip T Yanos
BACKGROUND: The uneven progression of mental health funding in the United States, and the way that the funding climate seems to be influenced by local and regional differences, raises the issue of what factors, including stigma, may impact mental health funding decisions. Criticisms that mental health stigma research is too individually-focused have led researchers to consider how broader, macro-level forms of stigma - such as structural stigma - intersect with micro-level forms of individual stigma...
2017: Israel Journal of Psychiatry and related Sciences
https://www.readbyqxmd.com/read/28857602/the-role-of-the-medial-prefrontal-cortex-in-the-generalization-of-conditioned-fear
#20
Kelsey N Spalding
OBJECTIVE: Fear generalization, the generalization of fear to innocuous stimuli, is a characteristic component of pathological anxiety. Neural models of fear generalization suggest the involvement of the medial prefrontal cortex (mPFC). However, conflicting empirical findings complicate our understanding of the role of the mPFC in pathological anxiety. To address important unanswered questions in this area, a detailed review and synthesis of results from human and nonhuman animal investigations of conditioned fear generalization was conducted...
August 31, 2017: Neuropsychology
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