Muito além do trauma: uma investigação sobre o papel das reações peritraumáticas sobre o transtorno de estresse pós-traumático / Beyond the trauma: an investigation of the role of peritraumatic reactions on posttraumatic stress disorder

O Transtorno de Estresse Pós-Traumático (TEPT) é uma condição debilitante que impacta significativamente a qualidade de vida dos seus portadores. Dentre vários fatores de risco para o TEPT, as reações peritraumáticas (RP), como a imobilidade tônica peritraumática (ITP), dissociação (DP) e reações físicas de pânico (RFP), estão entre as mais investigadas. No entanto, a maioria dos estudos avaliou essas RP separadamente, e o elo entre elas e o TEPT ainda não foi bem compreendido. Portanto, essa tese teve como objetivos: (i) estimar simultaneamente o efeito das três RP sobre o TEPT utilizando um instrumento validado; e (ii) avaliar se há efeito indireto da ITP sobre o TEPT mediado pelo sentimento de culpa/vergonha. Utilizamos modelagem de equações estruturais para analisar dados de 3211 participantes do Rio de Janeiro e de São Paulo. Tratamos as RP como variáveis latentes, selecionando desconfundidores específicos para cada reação. Nossas exposições foram as RP, sendo TEPT o desfecho. Calculamos odds ratios e intervalos de confiança de 95%. Utilizamos o Bayesian Information Criterion para comparar o ajuste de modelos não aninhados. Quando analisadas separadamente, todas as RP alcançaram significância estatística. No entanto, apenas DP (ORDP=1,8; IC95%:1,3-2,4) e RFP (ORRFP=2,5; IC95%:1,8-3,4) permaneceram estatisticamente significativas quando incluímos as três reações em um modelo com seus respectivos desconfundidores e correlações entre elas. Os resultados sugeriram um possível efeito da ITP sobre o TEPT (ORITP=1,4; IC95%:1,0-1,9). As interações entre as RP não foram estatisticamente significativas. Ao investigarmos o sentimento de culpa/vergonha como mediador entre ITP e TEPT, o efeito indireto alcançou apenas significância estatística limítrofe (ORITP(TNIE)=1,1; IC95%:1,0-1,2). Os efeitos direto (ORITP(PNDE)=1,3; IC95%: 0,8-1,8) e total (ORITP(TE)=1,4; IC95%:0,9-1,9) para ITP perderam significância quando todas as RP, seus desconfundidores e correlações entre elas fizeram parte do mesmo modelo. As demais RP, no entanto, permaneceram estatisticamente significativas (ORDP=1,7; IC95%:1,3-2,3 e ORRFP=2,5; IC95%:1,8-3,4). Nossos resultados mostraram que a DP e as RFP aumentaram o risco de TEPT mesmo quando consideradas em conjunto. A ITP pode ter efeito sobre o risco de TEPT, mas esse achado deve ser interpretado com cautela devido a significância limítrofe dessa RP em nosso modelo final. Também não identificamos uma mediação significativa entre ITP e TEPT pelos sentimentos de culpa/vergonha. Contudo, a significância limítrofe encontrada para o efeito indireto demanda investigações adicionais. Nossos achados reforçam a ideia de que as reações peritraumáticas devem ser analisadas e compreendidas como ocorrências simultâneas. Também seria oportuno que estudos envolvendo culpa/vergonha, ITP e TEPT focalizassem traumas caracterizados por aprisionamento e impossibilidade de escapar, dado que estas experiências são apontadas como mais susceptíveis para desencadear a ITP. (AU)

Posttraumatic stress disorder (PTSD) is a debilitating condition that greatly impacts quality of life. Among several PTSD risk factors, peritraumatic reactions (PR) such as peritraumatic tonic immobility (PTI), dissociation (PD) and physical panic reactions (PPR) are some of the most investigated. However, several studies have assessed these PR separately, and the pathway connecting them to PTSD is not well understood. Therefore, this thesis aimed to: (i) simultaneously estimate the effect of the three PR on PTSD using a validated instrument; and (ii) assess if there is an indirect effect of PTI on PTSD mediated by feelings of guilt/shame. We used structural equation modelling to analyse data from 3211 participants from Rio de Janeiro and São Paulo. We treated the PR as latent variables and selected specific confounders for each reaction. Our exposures were the PR, and PTSD was the outcome. We calculated odds ratios and 95% confidence intervals for each analysis. We also employed the Bayesian Information Criterion to compare the goodness of fit between non-nested models. Separately, all PR achieved statistically significant results. However, only PD (ORPD=1.8; 95%CI:1.3-2.4) and PPR (ORPPR=2.5; 95%CI:1.8-3.4) remained statistically significant when all three were included in a model with their respective confounders and correlations among all PR. Our findings suggested a possible effect of PTI on PTSD (ORPTI=1.4; 95%CI:1.0-1.9). Interactions between the PR were not statistically significant. When we investigated feelings of guilt/shame as the mediator between PTI and PTSD, the indirect effect achieved a borderline statistical significance (ORPTI(TNIE)=1.1; 95%CI:1.0-1.2). Direct (ORPTI(PNDE)=1.3; 95%CI:0.8-1.8) and total (ORPTI(TE)=1.4; 95%CI:0.9-1.9) effects lost their significance when all PR, their confounders and correlations were included in the same model. The other PR remained statistically significant (ORPD=1.7; 95%CI:1.3-2.3 and ORPPR=2.5; 95%CI:1.8-3.4). Our findings showed PD and PPR to increase the risk of PTSD even when considered in tandem. PTI could have an effect on PTSD, but this must be considered cautiously, as this PR only reached borderline significance in our final model. Feelings of guilt/shame did not significantly mediate PTI's effect on PTSD. However, a borderline statistical significance in the indirect effects warrants further investigation. Our findings reinforce the hypothesis that peritraumatic reactions should be analysed and understood as simultaneous occurrences, not as separate entities. It would also be appropriate for studies concerning guilt/shame, PTI and PTSD to focus on traumas characterized by imprisonment and feelings of inescapability, given that these experiences are allegedly more likely to trigger PTI. (AU)

Loss of Muscle Mass Induced by Aging / Pérdida de masa muscular inducida por el envejecimiento / Perda de massa muscular induzida por envelhecimento

Abstract Introduction : The world population ages rapidly, understanding the anatomo-functional changes of the muscle allows the implementation of effective actions in this age group. The objective of this work was to identify, through a review of scientific literature, the current advances in the molecular processes related to the loss of muscle mass induced by aging. Materials and Methods : The molecular causes of muscle mass loss induced by aging were reviewed through scientific articles from 2006 to 2016 on the Pubmed, Scielo and PEDro databases, combining the terms muscular aging, exercise and physical therapy. Results : Three sections were determined: 1) sarcopenia and aging, 2) molecular pathways of muscle mass loss induced by aging and 3) aging, exercise and functionality. Conclusion : Knowing the molecular basis of muscle mass loss induced by aging allows the physiotherapist to understand, evaluate and intervene related mechanisms to perform actions that improve the functionality and quality of life of older adults.

Resumen Introducción : la población mundial envejece rápidamente y comprender los cambios anatomo-funcionales del músculo permite implementar acciones eficaces en este grupo etario. El objetivo de este trabajo fue identificar, por medio de una revisión de literatura científica, los avances actuales de los procesos moleculares relacionados con la pérdida de masa muscular inducida por el envejecimiento. Materiales y métodos : se revisaron las causas moleculares de la pérdida de masa muscular inducida por el envejecimiento, mediante artículos científicos publicados desde 2006 hasta 2016 en las bases Pubmed, Scielo y PEDro, combinando los términos: muscular aging, exercise y physical therapy. Resultados : se determinaron tres apartados: 1) sarcopenia y envejecimiento, 2) vías moleculares de la pérdida de masa muscular inducida por el envejecimiento y 3) envejecimiento, ejercicio y funcionalidad. Conclusión : conocer las bases moleculares de la pérdida de masa muscular inducida por el envejecimiento permite al fisioterapeuta entender, evaluar e intervenir los mecanismos relacionados para realizar acciones que mejoren la funcionalidad y calidad de vida de los adultos mayores.

Resumo Introdução : a população mundial envelhece rapidamente e compreender as mudanças anátomo-funcionais do músculo, permite implementar ações eficazes neste grupo etário. O objetivo deste trabalho foi identificar através de uma revisão de literatura científica, os avanços atuais dos processos moleculares relacionado com a perda de massa muscular induzida pelo envelhecimento. Materiais e métodos : se revisaram as causas moleculares da perda de massa muscular induzida pelo envelhecimento, mediante artigos cientpificos desde 2006 até 2016 nas bases Pubmed, Scielo e PEDro, combinando os termos: muscular aging, exercise e physical therapy. Resultados : determinaram-se três apartados: 1) Sarcopenia e envelhecimento, 2) Vias moleculares da perda de massa muscular induzida pelo envelhecimento, e 3) Envelhecimento, exercício e funcionalidade. Conclusão : conhecer as bases moleculares da perda de massa muscular induzida pelo envelhecimento, permite ao fisioterapeuta compreender, avaliar e intervir os mecanismos relacionados para realizar ações que melhorem a funcionalidade e qualidade de vida dos adultos maiores.

Avaliação psicométrica do Peritraumatic Dissociative Experience Questionnaire (PDEQ) e proposta de um instrumento para avaliação de reações peritraumáticas / Psychometric evaluation of the Peritraumatic Dissociative Experience Questionnaire (PDEQ) and proposal of an instrument to evaluate Peritraumatic Reactions

O papel das reações vivenciadas durante experiências traumáticas tem sido alvo de interesse nos estudos sobre etiologia e prognóstico do transtorno de estresse pós-traumático. Essa tese avaliou a estrutura dimensional do instrumento mais utilizado para mensurar a dissociação peritraumática, o Peritraumatic Dissociative Experience Questionnaire (PDEQ). Adicionalmente, desenvolveu-se e avaliou-se as propriedades psicométricas do instrumento Peritraumatic Reactions Questionnaire (PTRQ), proposto para mensurar as três principais reações peritraumáticas (RP) no contexto do TEPT: dissociação peritraumática (DP), imobilidade tônica peritraumática (ITP) e reações físicas peritraumáticas (RFP). Os dados utilizados são originários de um estudo transversal realizado entre junho de 2007 e julho 2008 com amostras representativas da população acima de 15 anos das duas maiores cidades brasileiras. A amostra foi de 1.074 participantes no Rio de Janeiro e 2.145 em São Paulo que reportaram ao menos um evento traumático durante a vida. O primeiro artigo investigou a validade estrutural da versão brasileira do PDEQ. Análises de componentes principais indicaram a solução unidimensional corroborada por análises fatoriais confirmatórias (AFC) e de tipo exploratórias realizadas no Mplus. A adequação de ajuste dos modelos foi aceita para valores de CFI, TLI maiores que 0,95 e de RMSEA abaixo de 0,06. Os índices de modificação indicaram uma alta correlação residual entre os itens 9 ('dificuldade para entender o que estava acontecendo') e o item 10 ('desorientação') que foi corroborada nas duas amostras por AFC e sugere redundância de conteúdo. Análises de escalabilidade utilizando H de Loevinger e a hipóstese de dupla monotonicidade indicaram boas propriedades escalares. A versão reduzida com exclusão do item 9 foi proposta para utilização em estudos epidemiológicos. O segundo artigo reportou o processo de desenvolvimento de um instrumento integrado para avaliar RP. A etapa qualitativa avaliou a validade de conteúdo de 36 itens, sendo 30 provenientes das principais escalas utilizadas para mensurar as três principais RP e mais 6 itens elaborados por especialistas. O conjunto de 34 itens resultantes do processo qualitativo teve sua estrutura configural e métrica avaliadas a partir de AFC e de tipo exploratória para as duas amostras no Mplus. Modelos com CFI e TLI acima de 0,95 e de RMSEA menores que 0,06 foram considerados com ajuste satisfatório. A versão proposta do PTRQ conta com 29 itens distribuídos nas três dimensões (DP, ITP e RFP) mostrou boa estrutura fatorial e métrica, sendo recomendado para uso em estudos epidemiológicos. Espera-se que os resultados desta tese contribuam para o refinamento do processo de mensuração das RP, necessário para se avançar o conhecimento sobre o seu papel no desenvolvimento do TEPT, assim como nas propostas de intervenção precoce em indivíduos sob maior risco de desenvolvimento desse transtorno mental

The role of reactions occurring in the course of traumatic experiences has been of interest in studies regarding the etiology and prognosis of the posttraumatic stress disorder (PTSD). This thesis evaluated the dimensional structure of the most used instrument for measuring peritraumatic dissociation (PD) - the Peritraumatic Dissociative Experience Questionnaire (PDEQ). Additionally, we developed and evaluated the psychometric properties of the instrument denominated Peritraumatic Reaction Questionnaire (PTRQ), proposed for evaluating the three main peritraumatic reactions (PR) in the context of PTSD: dissociation (PD), tonic immobility (TIP) and physical panic reaction (PPR). Data were obtained from a cross-sectional study developed between June 2007 and July 2008, including a representative sample of people aged 15 or more from the two largest Brazilian cities. A sample of 3,229 participants reported at least one traumatic event during their lifetime, 1,074 in Rio de Janeiro and 2,145 in São Paulo. The first article investigated the structural validity of the Brazilian version of the PDEQ. Principal component analyzes indicated the one-dimensional solution corroborated by confirmatory and exploratory factor analysis (CFA) performed in Mplus. The models were fit if CFI, TLI values greater than 0.95 and RMSEA values below 0.06. Modification indices indicated a high residual correlation between item 9 ('difficulty understanding what was happening') and item 10 ('disorientation') which was corroborated in both samples by AFC and suggests content redundancy. Scalability analyzes using Loevinger H and double monotonicity hypothesis indicated good scalar properties. The shortened version excluding item 9 has been proposed for use in epidemiological studies. The second article reported on the process of developing an integrated instrument to assess PR. The qualitative stage evaluated the content validity of 36 items, 30 of them from the main scales used to measure the three main PR and 6 more items prepared by experts. The set of 34 items resulting from the qualitative process had their configuration and metric structure evaluated from CFA and exploratory type for both samples in Mplus. Models with CFI and TLI above 0.95 and RMSEA less than 0.06 were considered with satisfactory fit. The proposed version of the PTRQ has 29 items distributed in the three dimensions (PD, ITP and RFP) presented good factorial and metric structure, and is recommended for use in epidemiological studies. We expect that the findings from this thesis may contribute to the refinement of PR measurement necessary to advance the knowledge about its role in PTSD development, as well as proposals for early intervention in individuals at higher risk of developing this mental disorder

Episodios Ictales: Descripción de un Caso Clínico / Ictal events: a case report

Caso clínico de una paciente de once años que debuta con episodios de pérdida de tono y luego hipersomnolencia. Consulta en reiteradas ocasiones con el diagnóstico de epilepsia, con estudios electroencefalográficos y resonancia magnética cerebral, normales. Tratada durante un año con ac. valproico. Posteriormente se indica realización de Polisomnograma y Test de latencias múltiples de Sueño, confirmándose diagnóstico de narcolepsia y un trastorno del ánimo. Se inicia tratamiento con psicoestimulantes y antidepresivos. Evoluciona, con una mejoría de su cataplejía, hipersomnia y aspecto anímico. Se analiza caso, como diagnóstico diferencial de niños con episodios de pérdida de tono muscular e hipersomnolencia diurna, con conservación de conciencia y además se discute el manejo y las comorbilidades asociadas.

Summary: Case report of an eleven year old patient who debuts with hypersomnolence and episodes of muscle tone loss. She repeatedly receives a diagnosis of epilepsy, with normal EEG studies and brain MRI. She received a 12 month course of valproic acid treatment. A polysomnogram and multiple sleep latency test were subsequently performed, confirming a diagnosis of narcolepsy and a mood disorder. She begins treatment with antidepressants and psychostimulants. At follow up, she shows an improvement of her cataplexy, hypersomnia and mood disorder.We analyze this case to consider this pathology in the differential diagnosis of children with daytime hypersomnolence and episodes of muscle tone loss, with conserved awareness, as well as to discuss management and associated comorbidities.

Avaliação da imobilidade tônica em codornas de corte via análise de sobrevivência' / Tonic immobility evaluation in meat quail via survival analysis

Tonic immobility (TI) is a way to measure fear, as characterized by the reduced capacity to respond to external stimuli. The time spent in TI indicates the level of fear. Since TI is measured as the time until event occurrence, survival analysis stands out as a suitable statistical method to treat these data. We aimed to investigate the influence of possible factors (lines, sex and age) on fear behavior in meat quail (Coturnix coturnix) measured through TI by using survival analysis (non parametric Kaplan-Meyer method via logrank test). The dataset was composed by TI information provided by 50 animals from each line (UFV1 and UFV2) in each age (14 and 28 days of age), totalizing 200 records. Despite the slight difference between the two evaluated ages, there was no significance for this factor between each studied line, UFV1 (P= 0.1493) and UFV2 (P= 0.2583). The logrank test indicated significant difference (P= 0.0407) between levels of line/sex groups at 14 days of age. We noted that males from UFV2 line presented higher fear behavior in relation to males from UFV1 line. No significant differences were observed for this factor when considering 28 days of age.(AU)

Discrimination of anxiety- versus panic-like behavior in the wall lizard Tropidurus oreadicus

A behavioral test battery is proposed for wall lizards (Tropidurus oreadicus) that consists of inducing tonic immobility (TI) followed by post-TI behavioral scoring. After the induction of TI, the usual behavioral sequence was flight followed by freezing and tongue-flicking and/or thigmotaxis, with flight being more probable than freezing. These sequences were not observed after restraint in a normal upward position (which induced freezing but not TI) or after handling (which increased the probability of tongue-flicking). Alprazolam and imipramine selectively decreased the duration of TI as well as the following flight and freezing behavior. Tongue-flicking was increased by diazepam and alprazolam, whereas fluoxetine decreased it. Finally, thigmotaxis was reduced by diazepam, alprazolam, and imipramine but increased by fluoxetine. These results suggest that panic and anxiety can be discriminated pharmacologically in wall lizards...

Peritraumatic tonic immobility is associated with posttraumatic stress symptoms in undergraduate Brazilian students / A imobilidade tônica peritraumática está associada aos sintomas do transtorno de estresse pós-traumático em estudantes brasileiros de graduação

OBJECTIVE: Tonic immobility is a defensive reaction occurring under extreme life threats. Patients with posttraumatic stress disorder (PTSD) reporting peritraumatic tonic immobility show the most severe symptoms and a poorer response to treatment. This study investigated the predictive falue of tonic immobility for posttraumatic stress symptoms in a non-clinical sample. METHODS: One hundred and ninety-eight college students exposed to various life threatening events were selected to participate. The Posttraumatic Stress Disorder Checklist - Civilian Version (PCL-C) and tonic immobility questions were used. Linear regression models were fitted to investigate the association between peritraumatic tonic immobility and PCL-C scores. Peritraumatic dissociation, peritraumatic panic reactions, negative affect, gender, type of trauma, and time since trauma were considered as confounding variables. RESULTS: We found significant association between peritraumatic tonic immobility and PTSD symptoms in a non-clinical sample exposed to various traumas, even after regression controlled for confounding variables (β = 1.99, p = 0.017). CONCLUSIONS: This automatic reaction under extreme life threatening stress, although adaptive for defense, may have pathological consequences as implied by its association with PTSD symptoms.

OBJETIVO: A imobilidade tônica é uma resposta defensiva que ocorre sob ameaça extrema à vida. Pacientes com transtorno de estresse pós-traumático (TEPT) que relatam imobilidade tônica peritraumática são os que apresentam os sintomas mais graves e a pior resposta ao tratamento. Este estudo investigou o valor preditivo da imobilidade tônica para os sintomas de TEPT em uma amostra não clínica. MÉTODOS: Os participantes da pesquisa foram 198 estudantes universitários expostos a traumas diversos. A versão brasileira do Post-Traumatic Stress Disorder Checklist Civilian Version (PCL-C) e questões referentes à imobilidade tônica foram empregadas. Modelos de regressão linear foram utilizados para investigar a associação dos sintomas de estresse pós-traumático com a imobilidade tônica peritraumática. Foram consideradas como variáveis de confusão a dissociação peritraumática, as reações físicas de pânico peritraumática, o traço de afeto negativo, o gênero, o tipo de trauma e o tempo de trauma. RESULTADOS: Encontrou-se uma associação significativa entre a imobilidade tônica peritraumática e os sintomas de TEPT em uma amostra não clínica exposta a traumas diversos mesmo quando controlada por variáveis de confusão (β = 1,99; p = 0,017). CONCLUSÕES: Esta reação defensiva que ocorre sob intensa ameaça, apesar de adaptativa para a defesa, pode ter consequências patológicas como sugere sua associação aos sintomas de TEPT.

Defensive responses to threat scenarios in Brazilians reproduce the pattern of Hawaiian Americans and non-human mammals

A former study with scenarios conducted in Hawaii has suggested that humans share with non-human mammals the same basic defensive strategies - risk assessment, freezing, defensive threat, defensive attack, and flight. The selection of the most adaptive strategy is strongly influenced by features of the threat stimulus - magnitude, escapability, distance, ambiguity, and availability of a hiding place. Aiming at verifying if these strategies would be consistent in a different culture, 12 defensive scenarios were translated into Portuguese and adapted to the Brazilian culture. The sample consisted of male and female undergraduate students divided into two groups: 76 students, who evaluated the five dimensions of each scenario and 248 medical students, who chose the most likely response for each scenario. In agreement with the findings from studies of non-human mammal species, the scenarios were able to elicit different defensive behavioral responses, depending on features of the threat. "Flight" was chosen as the most likely response in scenarios evaluated as an unambiguous and intense threat, but with an available route of escape, whereas "attack" was chosen in an unambiguous, intense and close dangerous situation without an escape route. Less urgent behaviors, such as "check out", were chosen in scenarios evaluated as less intense, more distant and more ambiguous. Moreover, the results from the Brazilian sample were similar to the results obtained in the original study with Hawaiian students. These data suggest that a basic repertoire of defensive strategies is conserved along the mammalian evolution because they share similar functional benefits in maintaining fitness.

Experimental studies on treatment of depression with YJ-XCC1Z3 in mouse models / 中国中药杂志

<p><b>OBJECTIVE</b>To evaluate the pre-clinical effect of YJ-XCC1Z3 on the treatment of depression with the mice mouse.</p><p><b>METHOD</b>YJ-XCC1Z3 was administered at the dose of 405 mg x kg(-1) and 135 mg x kg(-1) to observe the locomotor activity with the mouse locomotor activity recorder apparatus, to observe the effect of YJ-XCC1Z3 on the duration of immohility in the mouse forced swimming test and tail suspension test, to observe the effect of YJ-XCC1Z3 on the body temperature and the metabolism of monoamine neurotransmitters in mouse brain in the mouse model of reserpine induced hypothermia, and to observe the effect of YJ-XCC1 Z3 on the times of 5-HTP induced head-twitches in mice.</p><p><b>RESULT</b>There were no significant changes in the locomotor activity, but a significant reduction in the immobility time was observed in the mice treated with YJ-XCC1Z3 405 mg x kg(-1) and imipramine in the forced swimming test and the tail suspension test. YJ-XCC1Z3 135 mg x kg(-1) and 405 mg x kg(-1) could improve the range of reserpine induced hypothermia in mice, and the latter could also enhance the times of 5-HTP induced head-twitches in mice. YJ-XCC1Z3 405 mg x kg(-1) and 135 mg x kg(-1) could increase the content of 5-HT and NE and decrease the ratio of 5-HIAA/5-HT in mouse brain, but the dose of 405 mg x kg(-1) could decrease the content of DA. The dose of 405 mg x kg(-1) could increase the content of 5-HIAA and had no obvious effect on the content of HVA and DOPAC.</p><p><b>CONCLUSION</b>YJ-XCC1Z3 shows potent antidepressant effect by improving the behaviour of the mouse in depression and not inducing hyperlocomotion in the mice. This effect results in the increase of the content of 5-HT and NE in the mouse brain. YJ-XCC1Z3 can decrease the metabolism of 5-HT to effect the content of 5-HT.</p>

Potentiation of pentobarbital hypnosis by Rosa damascena in mice.

Rosa damascena has been found to act on central nervous system including brain. It inhibits the reactivity of the hypothalamous and pituitary systems in rat. In traditional medicine hypnotic effect of Rose is also suggested. In the present study hypnotic effect of ethanolic, aqueous and chloroformic extracts of R. damascena was investigated in mice. Hypnotic method was based on potentiation of pentobarbital induced sleeping time by extracts. Three doses of extracts (100, 500 and 1000 mg/kg) were injected i.p. in comparison with diazepam (3mg/kg) as positive control and saline as negative control. After 30 min of injection of extracts, pentobarbital (30mg/kg) was injected and increase in sleeping time by extracts was recorded. The results showed that the ethanolic and aqueous extracts in 500 and 1000 mg/kg doses significantly increased pentobarbital induced sleeping time which was comparable to diazepam. The chloroformic extract had no hypnotic effect.

Estímulos emocionais: processamento sensorial e respostas motoras / Emotional stimuli: sensory processing and motor responses

A emoçäo pode ser funcionalmente considerada como uma disposiçäo à açäo que prepara o organismo para comportamentos relacionados à aproximaçäo e esquiva. Para preparar uma saída motora apropriada, o organismo tem que ser eficiente na codificaçäo de estímulos relevantes. Neste trabalho, apresentamos evidências a partir de estudos de neuroimagem que revelam que a visualizaçäo de imagens emocionais promove uma maior ativaçäo do córtex visual do que a observaçäo de figuras neutras. Além desta facilitaçäo do processamento sensorial, os estímulos emocionais desencadeiam reaçöes somáticas e vegetativas. Registros da dinâmica postural e da freqüência cardíaca enquanto voluntários assistiam a um bloco de figuras desagradáveis revelou uma reduçäo significativa na oscilaçäo corporal e bradicardia. Uma investigaçäo paralela mostrou que o tempo de reaçäo também lentifica após a visualizaçäo de figuras negativas. Este conjunto de respostas - imobilidade, bradicardia e tempo de reaçäo mais lento - pode refletir o engajamento do sistema defensivo, similar às reaçöes defensivas desencadeadas em ambiente natural por estímulos ameaçadores distantes. Em resumo, o sistema afetivo influencia um nível precoce de codificaçäo sensorial e a saída motora favorecendo, portanto, disposiçöes para as açöes apropriadas