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Pesquisa : F01.145.113.555 [Categoria DeCS]
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  1 / 960 MEDLINE  
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PMID:28416629
Autor:King G; Scott E; Graham BM; Richardson R
Endereço:School of Psychology, The University of New South Wales, UNSW, Sydney, 2052, Australia.
Título:Individual differences in fear extinction and anxiety-like behavior.
Fonte:Learn Mem; 24(5):182-190, 2017 May.
ISSN:1549-5485
País de publicação:United States
Idioma:eng
Resumo:There is growing appreciation for the substantial individual differences in the acquisition and inhibition of aversive associations, and the insights this might give into identifying individuals particularly vulnerable to stress and psychopathology. We examined whether animals that differed in rate of extinction (i.e., Fast versus Slow) were different in their response to an acute stress in adulthood or following a chronic stress that occurred either early or later in life. We found that Slow Extinguishers had significantly poorer extinction retention than Fast Extinguishers, but an acute stressor did not differentially affect anxiety-like behavior in the two groups. Further, while exposure to chronic stress in adulthood did not impact on the extinction phenotypes or anxiety-like behavior, exposure to chronic stress early in life affected both extinction retention and anxiety-like behavior. These findings have implications for the development of a more nuanced approach to identifying those most at risk of anxiety disorders.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:W980KJ009P (Corticosterone)


  2 / 960 MEDLINE  
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PMID:28388632
Autor:Glover LR; Schoenfeld TJ; Karlsson RM; Bannerman DM; Cameron HA
Endereço:National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland, United States of America.
Título:Ongoing neurogenesis in the adult dentate gyrus mediates behavioral responses to ambiguous threat cues.
Fonte:PLoS Biol; 15(4):e2001154, 2017 Apr.
ISSN:1545-7885
País de publicação:United States
Idioma:eng
Resumo:Fear learning is highly adaptive if utilized in appropriate situations but can lead to generalized anxiety if applied too widely. A role of predictive cues in inhibiting fear generalization has been suggested by stress and fear learning studies, but the effects of partially predictive cues (ambiguous cues) and the neuronal populations responsible for linking the predictive ability of cues and generalization of fear responses are unknown. Here, we show that inhibition of adult neurogenesis in the mouse dentate gyrus decreases hippocampal network activation and reduces defensive behavior to ambiguous threat cues but has neither of these effects if the same negative experience is reliably predicted. Additionally, we find that this ambiguity related to negative events determines their effect on fear generalization, that is, how the events affect future behavior under novel conditions. Both new neurons and glucocorticoid hormones are required for the enhancement of fear generalization following an unpredictably cued threat. Thus, adult neurogenesis plays a central role in the adaptive changes resulting from experience involving unpredictable or ambiguous threat cues, optimizing behavior in novel and uncertain situations.
Tipo de publicação: COMPARATIVE STUDY; JOURNAL ARTICLE
Nome de substância:0 (Glucocorticoids)


  3 / 960 MEDLINE  
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PMID:28362231
Autor:Alban MW; Pocknell V
Endereço:a Northern Arizona University.
Título:Cognitive Factors Affecting Freeze-like Behavior in Humans.
Fonte:J Gen Psychol; 144(2):140-156, 2017 Apr-Jun.
ISSN:1940-0888
País de publicação:United States
Idioma:eng
Resumo:Contemporary research on survival-related defensive behaviors has identified physiological markers of freeze/flight/fight. Our research focused on cognitive factors associated with freeze-like behavior in humans. Study 1 tested if an explicit decision to freeze is associated with the psychophysiological state of freezing. Heart rate deceleration occurred when participants chose to freeze. Study 2 varied the efficacy of freezing relative to other defense options and found "freeze" was responsive to variations in the perceived effectiveness of alternative actions. Study 3 tested if individual differences in motivational orientation affect preference for a "freeze" option when the efficacy of options is held constant. A trend in the predicted direction suggested that naturally occurring cognitions led loss-avoiders to select "freeze" more often than reward-seekers. In combination, our attention to the cognitive factors affecting freeze-like behavior in humans represents a preliminary step in addressing an important but neglected research area.
Tipo de publicação: JOURNAL ARTICLE


  4 / 960 MEDLINE  
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PMID:27989459
Autor:Zingg B; Chou XL; Zhang ZG; Mesik L; Liang F; Tao HW; Zhang LI
Endereço:Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA; Neuroscience Graduate Program, University of Southern California, Los Angeles, CA 90033, USA.
Título:AAV-Mediated Anterograde Transsynaptic Tagging: Mapping Corticocollicular Input-Defined Neural Pathways for Defense Behaviors.
Fonte:Neuron; 93(1):33-47, 2017 Jan 04.
ISSN:1097-4199
País de publicação:United States
Idioma:eng
Resumo:To decipher neural circuits underlying brain functions, viral tracers are widely applied to map input and output connectivity of neuronal populations. Despite the successful application of retrograde transsynaptic viruses for identifying presynaptic neurons of transduced neurons, analogous anterograde transsynaptic tools for tagging postsynaptically targeted neurons remain under development. Here, we discovered that adeno-associated viruses (AAV1 and AAV9) exhibit anterograde transsynaptic spread properties. AAV1-Cre from transduced presynaptic neurons effectively and specifically drives Cre-dependent transgene expression in selected postsynaptic neuronal targets, thus allowing axonal tracing and functional manipulations of the latter input-defined neuronal population. Its application in superior colliculus (SC) reveals that SC neuron subpopulations receiving corticocollicular projections from auditory and visual cortex specifically drive flight and freezing, two different types of defense behavior, respectively. Together with an intersectional approach, AAV-mediated anterograde transsynaptic tagging can categorize neurons by their inputs and molecular identity, and allow forward screening of distinct functional neural pathways embedded in complex brain circuits.
Tipo de publicação: JOURNAL ARTICLE; VIDEO-AUDIO MEDIA
Nome de substância:EC 2.7.7.- (Cre recombinase); EC 2.7.7.- (DNA Nucleotidyltransferases); EC 2.7.7.- (FLP recombinase); EC 2.7.7.- (Integrases)


  5 / 960 MEDLINE  
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PMID:28117439
Autor:Fadok JP; Krabbe S; Markovic M; Courtin J; Xu C; Massi L; Botta P; Bylund K; Müller C; Kovacevic A; Tovote P; Lüthi A
Endereço:Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland.
Título:A competitive inhibitory circuit for selection of active and passive fear responses.
Fonte:Nature; 542(7639):96-100, 2017 02 02.
ISSN:1476-4687
País de publicação:England
Idioma:eng
Resumo:When faced with threat, the survival of an organism is contingent upon the selection of appropriate active or passive behavioural responses. Freezing is an evolutionarily conserved passive fear response that has been used extensively to study the neuronal mechanisms of fear and fear conditioning in rodents. However, rodents also exhibit active responses such as flight under natural conditions. The central amygdala (CEA) is a forebrain structure vital for the acquisition and expression of conditioned fear responses, and the role of specific neuronal sub-populations of the CEA in freezing behaviour is well-established. Whether the CEA is also involved in flight behaviour, and how neuronal circuits for active and passive fear behaviour interact within the CEA, are not yet understood. Here, using in vivo optogenetics and extracellular recordings of identified cell types in a behavioural model in which mice switch between conditioned freezing and flight, we show that active and passive fear responses are mediated by distinct and mutually inhibitory CEA neurons. Cells expressing corticotropin-releasing factor (CRF ) mediate conditioned flight, and activation of somatostatin-positive (SOM ) neurons initiates passive freezing behaviour. Moreover, we find that the balance between conditioned flight and freezing behaviour is regulated by means of local inhibitory connections between CRF and SOM neurons, indicating that the selection of appropriate behavioural responses to threat is based on competitive interactions between two defined populations of inhibitory neurons, a circuit motif allowing for rapid and flexible action selection.
Tipo de publicação: JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
Nome de substância:51110-01-1 (Somatostatin); 9015-71-8 (Corticotropin-Releasing Hormone)


  6 / 960 MEDLINE  
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PMID:27806255
Autor:Kiyokawa Y; Takeuchi Y
Endereço:Laboratory of Veterinary Ethology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan. Electronic address: akiyo@mail.ecc.u-tokyo.ac.jp.
Título:Social buffering ameliorates conditioned fear responses in the presence of an auditory conditioned stimulus.
Fonte:Physiol Behav; 168:34-40, 2017 Jan 01.
ISSN:1873-507X
País de publicação:United States
Idioma:eng
Resumo:Social buffering is a phenomenon in which stress in an animal is ameliorated when the subject is accompanied by a conspecific animal(s) during exposure to distressing stimuli. Previous studies of social buffering of conditioned fear responses in rats have typically used a 3-s auditory conditioned stimulus (CS) as a stressor, observing stress responses during a specified experimental period. Because a 3-s CS is extremely short compared with a typical experimental period, freezing has thus been observed primarily in the absence of the CS. Therefore, it has been unclear whether social buffering ameliorates conditioned fear responses in the presence of the CS. To clarify this issue, the current study assessed the effects of social buffering on conditioned fear responses in the presence of a 20-s CS. We measured the percentage of time spent freezing during the 20-s period following the onset of the CS. When conditioned subjects were exposed to the 20-s CS alone, they exhibited a high percentage of freezing in the presence of the CS. The presence of another non-conditioned rat completely blocked this response. The same result was observed when freezing was observed primarily in the absence of the 3-s CS. In addition, we confirmed that the presence of an associate ameliorated conditioned fear responses induced by a 20-s CS or 3-s CS when the duration and frequency of fear responses was measured. These findings indicate that social buffering ameliorates conditioned fear responses in the presence of an auditory CS.
Tipo de publicação: JOURNAL ARTICLE


  7 / 960 MEDLINE  
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PMID:28160752
Autor:Butler JS; Fearon C; Killane I; Waechter SM; Reilly RB; Lynch T
Endereço:Trinity Centre for Bioengineering, Trinity College, The University of Dublin, Dublin 2, Ireland; School of Engineering, Trinity College, The University of Dublin, Dublin 2, Ireland; School of Mathematical Sciences, Dublin Institute of Technology, Kevin Street, Dublin, Ireland.
Título:Motor preparation rather than decision-making differentiates Parkinson's disease patients with and without freezing of gait.
Fonte:Clin Neurophysiol; 128(3):463-471, 2017 Mar.
ISSN:1872-8952
País de publicação:Netherlands
Idioma:eng
Resumo:OBJECTIVE: Freezing of gait (FOG) is a brief, episodic phenomenon affecting over half of people with Parkinson's disease (PD) and leads to significant morbidity. The pathophysiology of FOG remains poorly understood but is associated with deficits in cognitive function and motor preparation. METHOD: We studied 20 people with PD (10 with FOG, 10 without FOG) and performed a timed response target detection task while electroencephalographic data were acquired. We analysed the data to detect and examine cortical markers of cognitive decision making (P3b or centroparietal positivity, CPP) and motor readiness potential. We analysed current source density (CSD) to increase spatial resolution and allow identification of distinct signals. RESULTS: There was no difference in the P3b/CPP response between people with PD with and without FOG, suggesting equivalent cognitive processing with respect to decision-making. However, the FOG group had significant difference with an earlier onset and larger amplitude of the lateralized readiness potential. Furthermore, the amplitude of the lateralised readiness potential correlated strongly with total Frontal Assessment Battery score. CONCLUSIONS: The difference in lateralized readiness potentials may reflect excessive recruitment of lateral premotor areas to compensate for dysfunction of the supplementary motor area and resultant loss of automatic motor control. This early, excessive recruitment of frontal networks occurs in spite of equivalent motor scores and reaction times between groups. SIGNIFICANCE: The saturation of frontal processing mechanisms could help explain deficits in attentional set-shifting, dual-tasking and response inhibition which are frequently reported in FOG.
Tipo de publicação: JOURNAL ARTICLE


  8 / 960 MEDLINE  
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Quillfeldt, Jorge A
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PMID:28100032
Autor:Pedraza LK; Sierra RO; Crestani AP; Quillfeldt JA; de Oliveira Alvares L
Endereço:Laboratório de Neurobiologia da Memória, Biophysics Department, Biosciences Institute, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
Título:Sequential learning during contextual fear conditioning guides the rate of systems consolidation: Implications for consolidation of multiple memory traces.
Fonte:Hippocampus; 27(5):518-528, 2017 May.
ISSN:1098-1063
País de publicação:United States
Idioma:eng
Resumo:Systems consolidation has been described as a time-dependent reorganization process involving the neocortical and hippocampal networks underlying memory storage and retrieval. Previous studies of our lab were able to demonstrate that systems consolidation is a dynamic process, rather than a merely passive, time-dependent phenomenon. Here, we studied the influence of sequential learning in contextual fear conditioning (CFC) with different training intensities in the time-course of hippocampal dependency and contextual specificity. We found that sequential learning with high-intensity shocks during CFC induces generalization of the first learning (context A) and maintains contextual specificity of the second learning (context B) 15 days after acquisition. Moreover, subsequent experiences reorganize brain structures involved in retrieval, accelerating the involvement of cortical structures and diminishing the hippocampal participation. Exposure to original context before novelty seems to only induce context specificity in hippocampal-dependent memories. We propose that systems consolidation could be considered a potential biological mechanism for reducing possible interferences between similar memory traces. © 2017 Wiley Periodicals, Inc.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (GABA-A Receptor Agonists); 0 (Receptors, GABA-A); 2763-96-4 (Muscimol)


  9 / 960 MEDLINE  
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PMID:27624121
Autor:Owens E; Josephs KA; Savica R; Hassan A; Klassen B; Bower J; Maraganore D; Matsumoto J; Ahlskog JE
Endereço:Department of Neurology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA. eowens1@gmail.com.
Título:The clinical spectrum and natural history of pure akinesia with gait freezing.
Fonte:J Neurol; 263(12):2419-2423, 2016 Dec.
ISSN:1432-1459
País de publicação:Germany
Idioma:eng
Resumo:Gait freezing as a presenting and relatively restricted condition is uncommon but a distinctive disorder. This entity was initially defined as "pure akinesia with gait freezing", and later a neuropathological substrate of progressive supranuclear palsy has been recognized. Limited studies have reported the clinical evolution after presentation, which is important for patient counseling. The objective of this study was to assess the demographic and clinical features, treatment-response, neuroimaging, and evolution of pure akinesia with gait freezing. A retrospective review of patients with this phenotype as previously defined was performed. Patients included had no or minimal limb rigidity and/or bradykinesia and no resting tremor, and all underwent neuroimaging of the brain after onset. Inclusion criteria were met by 30 patients, who were followed up to 21 years after symptom onset. During their course, 28 patients had falls (93 %), 12 patients had dysarthria (40 %), and 13 had handwriting changes (43 %). All patients had progression of their gait disorder over time, but with a variable interval until falls occurred. None of the patients developed vertical gaze palsy or met diagnostic criteria for an alternative parkinsonian disorder. Pure akinesia with gait freezing is a distinctive disorder that can be recognized in the clinic. Despite the previously reported progressive supranuclear palsy-like neuropathology, the clinical course is much less aggressive and disabling than classic Richardson syndrome, although fall risk eventually develops in nearly all patients. Bradykinesia, tremor, and rigidity do not develop, distinguishing pure akinesia with gait freezing from Parkinson's disease and other parkinsonian disorders.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Dopamine Agents); 46627O600J (Levodopa)


  10 / 960 MEDLINE  
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PMID:27615803
Autor:Polverino G; Bierbach D; Killen SS; Uusi-Heikkilä S; Arlinghaus R
Endereço:Department of Biology and Ecology of Fishes, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Muggelseedamm 310, 12587, Berlin, Germany. polverino@igb-berlin.de.
Título:Body length rather than routine metabolic rate and body condition correlates with activity and risk-taking in juvenile zebrafish Danio rerio.
Fonte:J Fish Biol; 89(5):2251-2267, 2016 Nov.
ISSN:1095-8649
País de publicação:England
Idioma:eng
Resumo:In this study, the following hypotheses were explored using zebrafish Danio rerio: (1) individuals from the same cohort differ consistently in activity and risk-taking and (2) variation in activity and risk-taking is linked to individual differences in metabolic rate, body length and body condition. To examine these hypotheses, juvenile D. rerio were tested for routine metabolic rate and subsequently exposed to an open field test. Strong evidence was found for consistent among-individual differences in activity and risk-taking, which were overall negatively correlated with body length, i.e. larger D. rerio were found to be less active in a potentially dangerous open field and a similar trend was found with respect to a more direct measure of their risk-taking tendency. In contrast, routine metabolic rate and body condition were uncorrelated with both activity and risk-taking of juvenile D. rerio. These findings suggest that body length is associated with risk-related behaviours in juvenile D. rerio for which larger, rather than smaller, individuals may have a higher risk of predation, while the role for routine metabolic rate is relatively limited or non-existent, at least under the conditions of the present study.
Tipo de publicação: JOURNAL ARTICLE



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