This Master's dissertation explored whether a rapid orienting of attention toward or away from social stress information during a restful state, relates to the magnitude of glucocorticoids (GC) released in response to a stressor, the Trier Social Stress Test (TSST). It also assessed whether childhood rearing in a low socioeconomic status (SES) context mediates this relationship. Subjects rested for 45 minutes during which time they completed a modified version of Posner's attention paradigm, comprising social stress words. Immediately following, participants were exposed to the stressor. Results indicated that a rapid attentional engagement toward social stress words associated with pronounced GC responses to the TSST. Fast engagers displayed lower self-esteem and did not differ in terms of their past SES. These findings demonstrate that attentional biases for social stress information at rest combine with diminished self-esteem to predict the magnitude of GC released during psychological stress irrespective of early SES conditions.

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This dissertation presents three experiments designed to demonstrate the effects of cognitive, emotional and psychosocial factors on pain perception in humans and to identify potential neuroanatomical substrates of attentional and emotional pain modulation. / The first two chapters provide an introduction, including the statement of the rationale and objectives of this Ph.D. project (Chapter 1) and an overview of the relevant background literature (Chapter 2). / Chapter 3 presents a voxel-based morphometry study on the neural correlates of attentional and emotional pain modulation. In agreement with the observation that manipulations of emotion and attention differentially affect pain perception, the results of this experiment suggest that separate neuroanatomical substrates may underlie these pain modulations: the right lateral orbitofrontal, left medial prefrontal, and bilateral entorhinal cortices appear to be implicated in emotional pain modulation, while the right putamen appears to be involved in attentional pain modulation. / The study described in Chapter 4 shows that the experimental manipulation of mood using emotionally-laden visual stimuli preferentially alters pain unpleasantness, leaving pain intensity unaffected. This study replicates the psychophysical observations presented in the study of Chapter 3 (and in previous reports), which used odors to manipulate emotional state, therefore suggesting the independence of this phenomenon from the mood induction technique employed. / The study in Chapter 5 shows that empathy has an effect on pain perception as well, which cannot be explained by mood effects. Participants for whom a state of high empathy was evoked rated painful stimuli applied to themselves as more intense and unpleasant than did those in a state of low empathy; furthermore, the state empathy ratings correlated with the pain ratings. / By showing that emotional state, attention and empathy can influence pain perception, the work in this thesis provides evidence demonstrating that the pain experience can be significantly molded by top-down factors, and is therefore far from being solely determined by the physical properties of the noxious stimulation. These observations might partially explain why the pain response in certain situations appears disproportionately large, or surprisingly small, in relation to the noxious stimulation, and support the utility of psychological methods in the management of pain symptoms.

No description available.

In this paper, we investigate how controlled changes to image properties and orientation affect eye movements for repeated viewings of images of natural scenes. We make changes to images by manipulating low-level image content (such as luminance or chromaticity) and/or inverting the image. We measure the effects of these manipulations on human scanpaths (the spatial and chronological path of fixations), additionally comparing these effects to those predicted by a widely used saliency model (L. Itti & C. Koch, 2000). Firstly we find that repeated viewing of a natural image does not significantly modify the previously known repeatability (S. A. Brandt & L. W. Stark, 1997; D. Noton & L. Stark, 1971) of scanpaths. Secondly we find that manipulating image features does not necessarily change the repeatability of scanpaths, but the removal of luminance information has a measurable effect. We also find that image inversion appears to affect scene perception and recognition and may alter fixation selection (although we only find an effect on scanpaths with the additional removal of luminance information). Additionally we confirm that visual saliency as defined by L. Itti and C. Koch's (2000) model is a poor predictor of real observer scanpaths and does not predict the small effects of our image manipulations on scanpaths.

INTRODUÇÃO: O termo memória operacional (MO) refere-se a um constructo cognitivo capaz de armazenar e manter a informação acessível para uso determinado por um tempo limitado, possibilitando a manipulação de diversas informações simultâneas e sequenciais como operações matemáticas longas ou complexas, compreensão de palavras pouco frequentes, extensas ou frases complexas. A linguagem está entre as funções cognitivas que dependem do funcionamento da memória operacional e pode estar comprometida em várias condições patológicas, dentre elas o traumatismo cranioencefálico (TCE). Dados da literatura referentes a essa população ainda são restritos ou pouco consistentes. OBJETIVOS: investigar se o teste n-back é uma medida válida para identificar o déficit de memória em pacientes com TCE, estabelecer nota de corte e curva ROC do teste n-back, comparar o desempenho entre os indivíduos saudáveis e aqueles que sofreram TCE, comparar o teste n-back com os testes de linguagem e aspectos da lesão neurológica, tais como gravidade e tempo, tempo de coma e localização hemisférica da lesão nos resultados para verificar o desempenho e a relevância na separação dos casos em pacientes e controles.MÉTODOS: 53 indivíduos brasileiros (26 adultos com TCE e 30 adultos saudáveis) foram avaliados por bateria de estímulos verbais auditivos para verificar diferenças inter-grupos na capacidade de processamento da memória operacional, quanto ao numero de respostas corretas (acurácia), capacidade máxima de processamento na memória operacional (span) e também verificar a relação da memória operacional com habilidades linguísticas, através da comparação de testes. RESULTADOS: na comparação entre os pacientes e os indivíduos do grupo controle observou-se diferença estatisticamente significante entre os grupos tanto para os testes de base quanto para os resultados do n-back. Os grupos foram estatisticamente pareados em relação às variáveis sócio-demográficas (idade, escolaridade e gênero). O modelo estatístico com as variáveis do teste n-back demonstrou ótima separação dos casos em pacientes/ controle com a área sob a curva ROC de 89%. O modelo também mostrou convergência com os testes de linguagem para compreensão auditiva de sentenças, fluência verbal e aspectos discursivos-pragmáticos e com o nível cognitivo. O lado da lesão foi estatisticamente significante para o n-back, fluência verbal e discurso conversacional. CONCLUSÃO: Os resultados mostram que o n-back na maneira como foi desenhado é capaz de diferenciar os indivíduos alterados e os normais na habilidade de memória operacional. No estudo foi possível discriminar o comportamento de indivíduos com lesão encefálica adquirida e indivíduos saudáveis quanto à medida de acurácia e capacidade máxima de manipulação da informação na memória operacional. Esse comportamento reflete o funcionamento linguístico e cognitivo que se correlaciona com o mecanismo de memória operacional / INTRODUCTION: The term working memory (WM) refers to a construct cognitive capability of storing and keeping information on line to a determined use for a limited time, enabling the manipulation of diverse simultaneous and sequential information such as long or complex mathematical operations, comprehension of less frequent words, extensive or complex sentences. The language is among the cognitive functions which depends on the operational memory behavior and may be engaged in many pathological conditions, among them the TBI (traumatic brain injury). Literature dada relative to such population are still restrict or weak. AIM: investigate whether the n -back task is a valid measure for identifying memory deficits in patients with TBI; establish cutoff and ROC curve of n-back task; to compare performance between normals individuals and those who have suffered TBI; to compare n-back task with tests of language and aspects of neurological injury, such as severity, coma and hemispheric laterality of the lesion to verify the performance and relevance in the separation of cases. METHODOS: 53 individuals Brazilians (26 adults with TBI and 30 healthy adults) were assessed by a battery of auditory verbal stimuli for detecting differences between groups in the processing capacity of working memory, as the accuracy and span also check the relationship of working memory to language skills, through the comparison tests. RESULTS: in the comparison between patients and control subjects was observed statistically significant differences between groups thus to the tests as the basis tests as to results of the n -back. The groups were statistically matched in relation to socio-demographic variables (age, education and gender). The statistical model with variables of the n -back test showed good separation of cases where patients / control with the area under the ROC curve of 89 % . The model also showed convergence with language tests for auditory comprehension of sentences, verbal fluency and pragmatic - discursive aspects and the cognitive level. The side of the lesion was statistically significant for the n -back, verbal fluency and conversational discourse. CONCLUSION: the results demonstrated that the n-back on the way it was designed is able to distinguish the changed individuals and the normal on the working memory ability. On the study it was possible to discriminate the behaviors of individuals with acquired brain injury and healthy individuals regarding the accuracy and maximum capacity of manipulating information on the working memory. Such behavior reflects the linguistic and cognitive function which correlates with the working memory mechanism

INTRODUÇÃO: O termo memória operacional (MO) refere-se a um constructo cognitivo capaz de armazenar e manter a informação acessível para uso determinado por um tempo limitado, possibilitando a manipulação de diversas informações simultâneas e sequenciais como operações matemáticas longas ou complexas, compreensão de palavras pouco frequentes, extensas ou frases complexas. A linguagem está entre as funções cognitivas que dependem do funcionamento da memória operacional e pode estar comprometida em várias condições patológicas, dentre elas o traumatismo cranioencefálico (TCE). Dados da literatura referentes a essa população ainda são restritos ou pouco consistentes. OBJETIVOS: investigar se o teste n-back é uma medida válida para identificar o déficit de memória em pacientes com TCE, estabelecer nota de corte e curva ROC do teste n-back, comparar o desempenho entre os indivíduos saudáveis e aqueles que sofreram TCE, comparar o teste n-back com os testes de linguagem e aspectos da lesão neurológica, tais como gravidade e tempo, tempo de coma e localização hemisférica da lesão nos resultados para verificar o desempenho e a relevância na separação dos casos em pacientes e controles.MÉTODOS: 53 indivíduos brasileiros (26 adultos com TCE e 30 adultos saudáveis) foram avaliados por bateria de estímulos verbais auditivos para verificar diferenças inter-grupos na capacidade de processamento da memória operacional, quanto ao numero de respostas corretas (acurácia), capacidade máxima de processamento na memória operacional (span) e também verificar a relação da memória operacional com habilidades linguísticas, através da comparação de testes. RESULTADOS: na comparação entre os pacientes e os indivíduos do grupo controle observou-se diferença estatisticamente significante entre os grupos tanto para os testes de base quanto para os resultados do n-back. Os grupos foram estatisticamente pareados em relação às variáveis sócio-demográficas (idade, escolaridade e gênero). O modelo estatístico com as variáveis do teste n-back demonstrou ótima separação dos casos em pacientes/ controle com a área sob a curva ROC de 89%. O modelo também mostrou convergência com os testes de linguagem para compreensão auditiva de sentenças, fluência verbal e aspectos discursivos-pragmáticos e com o nível cognitivo. O lado da lesão foi estatisticamente significante para o n-back, fluência verbal e discurso conversacional. CONCLUSÃO: Os resultados mostram que o n-back na maneira como foi desenhado é capaz de diferenciar os indivíduos alterados e os normais na habilidade de memória operacional. No estudo foi possível discriminar o comportamento de indivíduos com lesão encefálica adquirida e indivíduos saudáveis quanto à medida de acurácia e capacidade máxima de manipulação da informação na memória operacional. Esse comportamento reflete o funcionamento linguístico e cognitivo que se correlaciona com o mecanismo de memória operacional / INTRODUCTION: The term working memory (WM) refers to a construct cognitive capability of storing and keeping information on line to a determined use for a limited time, enabling the manipulation of diverse simultaneous and sequential information such as long or complex mathematical operations, comprehension of less frequent words, extensive or complex sentences. The language is among the cognitive functions which depends on the operational memory behavior and may be engaged in many pathological conditions, among them the TBI (traumatic brain injury). Literature dada relative to such population are still restrict or weak. AIM: investigate whether the n -back task is a valid measure for identifying memory deficits in patients with TBI; establish cutoff and ROC curve of n-back task; to compare performance between normals individuals and those who have suffered TBI; to compare n-back task with tests of language and aspects of neurological injury, such as severity, coma and hemispheric laterality of the lesion to verify the performance and relevance in the separation of cases. METHODOS: 53 individuals Brazilians (26 adults with TBI and 30 healthy adults) were assessed by a battery of auditory verbal stimuli for detecting differences between groups in the processing capacity of working memory, as the accuracy and span also check the relationship of working memory to language skills, through the comparison tests. RESULTS: in the comparison between patients and control subjects was observed statistically significant differences between groups thus to the tests as the basis tests as to results of the n -back. The groups were statistically matched in relation to socio-demographic variables (age, education and gender). The statistical model with variables of the n -back test showed good separation of cases where patients / control with the area under the ROC curve of 89 % . The model also showed convergence with language tests for auditory comprehension of sentences, verbal fluency and pragmatic - discursive aspects and the cognitive level. The side of the lesion was statistically significant for the n -back, verbal fluency and conversational discourse. CONCLUSION: the results demonstrated that the n-back on the way it was designed is able to distinguish the changed individuals and the normal on the working memory ability. On the study it was possible to discriminate the behaviors of individuals with acquired brain injury and healthy individuals regarding the accuracy and maximum capacity of manipulating information on the working memory. Such behavior reflects the linguistic and cognitive function which correlates with the working memory mechanism