Base de dados : MEDLINE
Pesquisa : F01.145.113.555 [Categoria DeCS]
Referências encontradas : 948 [refinar]
Mostrando: 1 .. 10   no formato [Longo]

página 1 de 95 ir para página                         

  1 / 948 MEDLINE  
              next record last record
seleciona
para imprimir
Fotocópia
Texto completo
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


  2 / 948 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
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


  3 / 948 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Quillfeldt, Jorge A
Texto completo
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)


  4 / 948 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
PMID:27613712
Autor:Karakoc M; Yon MI; Cakmakli GY; Ulusoy EK; Gulunay A; Oztekin N; Ak F
Endereço:Department of Neurology, Necip Fazil State Hospital, Kahramanmaras, Turkey.
Título:Pathophysiology underlying drooling in Parkinson's disease: oropharyngeal bradykinesia.
Fonte:Neurol Sci; 37(12):1987-1991, 2016 Dec.
ISSN:1590-3478
País de publicação:Italy
Idioma:eng
Resumo:We aimed to investigate the association between drooling and possible etiological factors in Parkinson's disease (PD) and to determine its effect on the quality of life. Demographic data of the 63 patients with idiopathic PD were recorded. Radboud Oral Motor Inventory for Parkinson's disease (ROMP) test was administered to all patients to evaluate speech, swallowing functions, and saliva control. The freezing of gait questionnaire (FOGQ) was used to evaluate gait and freezing of gait. Dynamic Parkinson gait scale (DYPAGS) was administered for the objective quantification of PD gait features. Disease severity was assessed by UPDRS and modified Hoehn & Yahr Scale. PD specific health-related quality was evaluated by PDQ-39 questionnaire. Drooling was only significantly correlated to UPDRS score; a stronger association was found between drooling and UPDRS 3 motor score; and a more significant association was determined between drooling and the bradykinesia questions of the motor part of UPDRS 3. Interestingly, no significant association was found between sialorrhea score and PDQ-39 score. Based on the results of this study, we concluded that oropharyngeal bradykinesia may be responsible for drooling in PD. In contrast to a general expectation, we did not find any adverse impact of drooling on the quality of life.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Antiparkinson Agents); 46627O600J (Levodopa)


  5 / 948 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
PMID:27538285
Autor:Zaichenko MI; Markevich VA; Grigoryan GA
Título:[Propranolol Impairs Memory Reconsolidation at Single and Multiple Paired with Tone Painful Electrocutaneous Stimulations].
Fonte:Zh Vyssh Nerv Deiat Im I P Pavlova; 66(2):220-8, 2016 Mar-Apr.
ISSN:0044-4677
País de publicação:Russia (Federation)
Idioma:rus
Resumo:In the current paper there were used two methods for assessment of the propranolol effect on reactivated memory at reconsolidation phase--a classical pavlovian conditioning and the two-ways escape reflex. The difference between these two models was that in the first case a tone was paired with electrocutaneous painful stimulation only once, while in the second case it was applied multiply. Reminding was produced in the first case by placing the animals into the same context, whereas in the second case by application of the same amount of pairings of conditional and unconditional stimuli as it was used at the first day of learning. Propranolol reduced intensity of freezing reaction on 25% from the baseline at the classical conditioning approach and practically led to disappearance of memory and complete regress of the two-ways escape reflex. There was suggested on existence of the possible different mechanisms of noradrenergic blockade on memory loss at the stage of its reconsolidation in the used models of learning.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Adrenergic beta-Antagonists); 9Y8NXQ24VQ (Propranolol)


  6 / 948 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
PMID:27409809
Autor:Dejean C; Courtin J; Karalis N; Chaudun F; Wurtz H; Bienvenu TC; Herry C
Título:Prefrontal neuronal assemblies temporally control fear behaviour.
Fonte:Nature; 535(7612):420-4, 2016 Jul 21.
ISSN:1476-4687
País de publicação:England
Idioma:eng
Resumo:Precise spike timing through the coordination and synchronization of neuronal assemblies is an efficient and flexible coding mechanism for sensory and cognitive processing. In cortical and subcortical areas, the formation of cell assemblies critically depends on neuronal oscillations, which can precisely control the timing of spiking activity. Whereas this form of coding has been described for sensory processing and spatial learning, its role in encoding emotional behaviour remains unknown. Fear behaviour relies on the activation of distributed structures, among which the dorsal medial prefrontal cortex (dmPFC) is known to be critical for fear memory expression. In the dmPFC, the phasic activation of neurons to threat-predicting cues, a spike-rate coding mechanism, correlates with conditioned fear responses and supports the discrimination between aversive and neutral stimuli. However, this mechanism does not account for freezing observed outside stimuli presentations, and the contribution of a general spike-time coding mechanism for freezing in the dmPFC remains to be established. Here we use a combination of single-unit and local field potential recordings along with optogenetic manipulations to show that, in the dmPFC, expression of conditioned fear is causally related to the organization of neurons into functional assemblies. During fear behaviour, the development of 4 Hz oscillations coincides with the activation of assemblies nested in the ascending phase of the oscillation. The selective optogenetic inhibition of dmPFC neurons during the ascending or descending phases of this oscillation blocks and promotes conditioned fear responses, respectively. These results identify a novel phase-specific coding mechanism, which dynamically regulates the development of dmPFC assemblies to control the precise timing of fear responses.
Tipo de publicação: JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T


  7 / 948 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
PubMed Central Texto completo
Texto completo
PMID:27335434
Autor:Koba S; Inoue R; Watanabe T
Endereço:Division of Integrative Physiology, Tottori University Faculty of Medicine, Yonago Tottori, Japan skoba@med.tottori-u.ac.jp.
Título:Role played by periaqueductal gray neurons in parasympathetically mediated fear bradycardia in conscious rats.
Fonte:Physiol Rep; 4(12), 2016 Jun.
ISSN:2051-817X
País de publicação:United States
Idioma:eng
Resumo:Freezing, a characteristic pattern of defensive behavior elicited by fear, is associated with a decrease in the heart rate. Central mechanisms underlying fear bradycardia are poorly understood. The periaqueductal gray (PAG) in the midbrain is known to contribute to autonomic cardiovascular adjustments associated with various emotional behaviors observed during active or passive defense reactions. The purpose of this study was to elucidate the role played by PAG neurons in eliciting fear bradycardia. White noise sound (WNS) exposure at 90 dB induced freezing behavior and elicited bradycardia in conscious rats. The WNS exposure-elicited bradycardia was mediated parasympathetically because intravenous administration of atropine abolished the bradycardia (P < 0.05). Moreover, WNS exposure-elicited bradycardia was mediated by neuronal activation of the lateral/ventrolateral PAG (l/vlPAG) because bilateral microinjection of muscimol, a GABAA agonist, into the l/vlPAG significantly suppressed the bradycardia. It is noted that muscimol microinjected bilaterally into the dorsolateral PAG had no effect on WNS exposure-elicited bradycardia. Furthermore, retrograde neuronal tracing experiments combined with immunohistochemistry demonstrated that a number of l/vlPAG neurons that send direct projections to the nucleus ambiguus (NA) in the medulla, a major origin of parasympathetic preganglionic neurons to the heart, were activated by WNS exposure. Based on these findings, we propose that the l/vlPAG-NA monosynaptic pathway transmits fear-driven central signals, which elicit bradycardia through parasympathetic outflow.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (GABA-A Receptor Agonists); 2763-96-4 (Muscimol)


  8 / 948 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
PMID:27287886
Autor:Ahnaou A; Drinkenburg WH
Endereço:Department of Neuroscience, Janssen Research and Development, Janssen Pharmaceutica N.V., Beerse, Belgium.
Título:Simultaneous Changes in Sleep, qEEG, Physiology, Behaviour and Neurochemistry in Rats Exposed to Repeated Social Defeat Stress.
Fonte:Neuropsychobiology; 73(4):209-23, 2016.
ISSN:1423-0224
País de publicação:Switzerland
Idioma:eng
Resumo:Depression is a heterogeneous disorder characterized by alterations at psychological, behavioural, physiological, neurophysiological, and neurochemical levels. Social stress is a prevalent stress in man, and the repeated social defeat stress model in rats has been proposed as being the rodent equivalent to loss of control, which in subordinate animals produces alterations that resemble several of the cardinal symptoms found in depressed patients. Here, rats followed a resident-intruder protocol for 4 consecutive days during which behavioural, physiological, and electroencephalographic (EEG) parameters were simultaneously monitored in subordinate rats. On day 5, prefrontal dopamine (DA) and hippocampal serotonin (5-HT) as well as corticosterone were measured in submissive rats that had visual, acoustic, and olfactory (but no physical) contact with a dominant, resident conspecific rat. Socially defeated rats demonstrated increases in ultrasonic vocalizations (20-25 KHz), freezing, submissive defensive behaviour, inactivity, and haemodynamic response, while decreases were found in repetitive grooming behaviour and body weight. Additionally, alterations in the sleep-wake architecture were associated with reduced active waking, enhanced light sleep, and increased frequency of transitions from light sleep to quiet wakefulness, indicating sleep instability. Moreover, the attenuation of EEG power over the frequency range of 4.2-30 Hz, associated with a sharp transient increase in delta oscillations, appeared to reflect increased brain activity and metabolism in subordinate animals. These EEG changes were synchronous with a marked increase in body temperature and a decrease in locomotor activity. Furthermore, psychosocial stress consistently increased 5-HT, DA, and corticosterone levels. The increased levels of cortical DA and hippocampal 5-HT during social threat may reflect a coping mechanism to promote alertness and psychological adaptation to provocative and threatening stimuli. These neurophysiological changes are hypothesized to be the consequence of dynamics in monoamine systems, which could be useful markers for disease progression in the aetiology of depression.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:333DO1RDJY (Serotonin); VTD58H1Z2X (Dopamine); W980KJ009P (Corticosterone)


  9 / 948 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
PMID:27279213
Autor:Tovote P; Esposito MS; Botta P; Chaudun F; Fadok JP; Markovic M; Wolff SB; Ramakrishnan C; Fenno L; Deisseroth K; Herry C; Arber S; Lüthi A
Endereço:Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland.
Título:Midbrain circuits for defensive behaviour.
Fonte:Nature; 534(7606):206-12, 2016 06 09.
ISSN:1476-4687
País de publicação:England
Idioma:eng
Resumo:Survival in threatening situations depends on the selection and rapid execution of an appropriate active or passive defensive response, yet the underlying brain circuitry is not understood. Here we use circuit-based optogenetic, in vivo and in vitro electrophysiological, and neuroanatomical tracing methods to define midbrain periaqueductal grey circuits for specific defensive behaviours. We identify an inhibitory pathway from the central nucleus of the amygdala to the ventrolateral periaqueductal grey that produces freezing by disinhibition of ventrolateral periaqueductal grey excitatory outputs to pre-motor targets in the magnocellular nucleus of the medulla. In addition, we provide evidence for anatomical and functional interaction of this freezing pathway with long-range and local circuits mediating flight. Our data define the neuronal circuitry underlying the execution of freezing, an evolutionarily conserved defensive behaviour, which is expressed by many species including fish, rodents and primates. In humans, dysregulation of this 'survival circuit' has been implicated in anxiety-related disorders.
Tipo de publicação: JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
Nome de substância:3KX376GY7L (Glutamic Acid)


  10 / 948 MEDLINE  
              first record previous record
seleciona
para imprimir
Fotocópia
Texto completo
PMID:27078100
Autor:Saunderson EA; Spiers H; Mifsud KR; Gutierrez-Mecinas M; Trollope AF; Shaikh A; Mill J; Reul JM
Endereço:Neuro-Epigenetics Research Group, University of Bristol, Bristol BS1 3NY, United Kingdom;
Título:Stress-induced gene expression and behavior are controlled by DNA methylation and methyl donor availability in the dentate gyrus.
Fonte:Proc Natl Acad Sci U S A; 113(17):4830-5, 2016 Apr 26.
ISSN:1091-6490
País de publicação:United States
Idioma:eng
Resumo:Stressful events evoke long-term changes in behavioral responses; however, the underlying mechanisms in the brain are not well understood. Previous work has shown that epigenetic changes and immediate-early gene (IEG) induction in stress-activated dentate gyrus (DG) granule neurons play a crucial role in these behavioral responses. Here, we show that an acute stressful challenge [i.e., forced swimming (FS)] results in DNA demethylation at specific CpG (5'-cytosine-phosphate-guanine-3') sites close to the c-Fos (FBJ murine osteosarcoma viral oncogene homolog) transcriptional start site and within the gene promoter region of Egr-1 (early growth response protein 1) specifically in the DG. Administration of the (endogenous) methyl donor S-adenosyl methionine (SAM) did not affect CpG methylation and IEG gene expression at baseline. However, administration of SAM before the FS challenge resulted in an enhanced CpG methylation at the IEG loci and suppression of IEG induction specifically in the DG and an impaired behavioral immobility response 24 h later. The stressor also specifically increased the expression of the de novo DNA methyltransferase Dnmt3a [DNA (cytosine-5-)-methyltransferase 3 alpha] in this hippocampus region. Moreover, stress resulted in an increased association of Dnmt3a enzyme with the affected CpG loci within the IEG genes. No effects of SAM were observed on stress-evoked histone modifications, including H3S10p-K14ac (histone H3, phosphorylated serine 10 and acetylated lysine-14), H3K4me3 (histone H3, trimethylated lysine-4), H3K9me3 (histone H3, trimethylated lysine-9), and H3K27me3 (histone H3, trimethylated lysine-27). We conclude that the DNA methylation status of IEGs plays a crucial role in FS-induced IEG induction in DG granule neurons and associated behavioral responses. In addition, the concentration of available methyl donor, possibly in conjunction with Dnmt3a, is critical for the responsiveness of dentate neurons to environmental stimuli in terms of gene expression and behavior.
Tipo de publicação: JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
Nome de substância:0 (Early Growth Response Protein 1); 0 (Egr1 protein, rat); 7LP2MPO46S (S-Adenosylmethionine); EC 2.1.1.37 (DNA (Cytosine-5-)-Methyltransferase); EC 2.1.1.37 (DNA methyltransferase 3A)



página 1 de 95 ir para página                         
   


Refinar a pesquisa
  Base de dados : MEDLINE Formulário avançado   

    Pesquisar no campo  
1  
2
3
 
           



Search engine: iAH v2.6 powered by WWWISIS

BIREME/OPAS/OMS - Centro Latino-Americano e do Caribe de Informação em Ciências da Saúde