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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
151

The psychophysiological consequences of depressed mood-related cognitive responses

Donaldson, Bruce William, n/a January 2006 (has links)
A substantial amount of research has investigated the psychophysiological profiles of various mood and emotional states; however, very little research has investigated individuals� mood responses from a psychophysiological perspective. As a result, little is known about the psychophysiological reactivity of individuals to various mood-related responses, or the ability of psychophysiological measures to differentiate between response styles. Furthermore, most investigations in the area of mood-related response styles have relied on participants self-report responses of their mood reactivity, which is considered to be susceptible to demand characteristics and response bias. Psychophysiological measures are thought to offer a unique and alternative measure of mood reactivity that can corroborate, or challenge self-report findings. They are considered to be less susceptible to demand effects than self-report, and can detect subtle changes in mood reactivity activity when an overt response is not apparent. In view of this, the primary objective of this thesis was to move beyond a reliance on subjective self-report measurements of mood reactivity, and to investigate the consequences of depressed mood-related cognitive response styles from a psychophysiological perspective. As part of this investigation, this thesis aims to address a number of theoretical and practical questions relating to the use of psychophysiological measures in mood research and clinical practice. The research is divided into four studies, each one focusing on a particular aspect of the investigation. The aim of Study 1 was to select and trial a laboratory-based mood induction procedure (MIP) and a self-report mood measure, with the intention of developing a reliable method of inducing and measuring depressed mood. Two film clips that contained either positive or negative affective content were presented to participants. Self-report responses on the Mood Scale confirmed that the negative film clip elicited a very unpleasant mood state with high emotional arousal, and that the positive film clip elicited a mildly pleasant mood state with low emotional arousal. The positive and negative Film Clip MIPs were then used in Studies 2 and 2a, to investigate participants� psychophysiological reactivity to induced mood. The aim of Studies 2 and 2a was to identify a set of psychophysiological measures that would differentiate between participants� mood states. In Study 2, the positive and negative Film Clip MIPs, from Study 1, were again presented to participants. Corrugator supercilii facial EMG activity, zygomaticus major facial EMG activity, skin conductance activity (SCA), heart rate (plethysmograph, sphygmomanometer), systolic blood pressure, diastolic blood pressure, and self-report ratings on the Mood Scale were recorded. Results confirmed that participant self-reported affective responses were similar to those reported in Study 1; however, mixed results were obtained in regards to individuals� psychophysiological responses to the MIPs. Facial EMG activity and heart rate (plethysmograph) were consistent with participants� self-reported mood, whereas, SCA and systolic blood pressure were inconsistent with participants� self-reported mood. Diastolic blood pressure and heart rate (sphygmomanometer) did not differentiate between the MIPs. As the results were somewhat contradictory to expectations, it was decided to further investigate the psychophysiology of induced mood in Study 2a, using a revised set of psychophysiological measures. In Study 2a, the positive and negative Film Clip MIPs were again presented to participants. Corrugator supercilii facial EMG activity, zygomaticus major facial EMG activity, SCA, heart rate (ECG), and finger temperature, were recorded along with participants� Mood Scale ratings. It was found that facial EMG activity and SCA, paralleled participant self-report as expected, and were most responsive to participants� change in mood state. Heart rate (ECG) and finger temperature did not clearly differentiate between the induced mood states. The aim of Study 3 was to conduct an experimental, laboratory-based investigation, into the psychophysiological and subjective mood consequences of two cognitive response styles: self-focused depressive rumination and external-focused distraction. As in the previous study, the negative Film Clip MIP and the Mood Scale were used to induce depressed mood and to measure participants� subjective mood state. Psychophysiological reactivity was recorded by measuring participants� corrugator supercilii facial EMG, zygomaticus major facial EMG, SCA, heart rate (sphygmomanometer), systolic blood pressure, and diastolic blood pressure. Trait response style was measured using the Response Style Questionnaire (RSQ; Nolen-Hoeksema & Morrow, 1991) and social desirability was measured using the Marlowe Crowne-Social Desirability Scale (MC-SDS; Crowne & Marlowe, 1960). As predicted by the Response Style Theory of depression (RST), increased self-reported negative mood was found when participants responded to the induced depressed mood, using a self-focused depressive rumination response style, rather than an external-focused distraction response style. Psychophysiological activity increased over the course of the negative Film Clip MIP for all psychophysiological measures, however, only corrugator supercilii facial EMG activity clearly differentiated between the cognitive response styles, in a way predicted by individuals� self-report responses. There was no evidence of a relationship between participants� trait response style and their psychophysiological reactivity or mood responses during the experiment. However, individuals high in trait rumination reported greater depressive symptomatology, and less mood reactivity during the experiment, than those high in trait distraction. Furthermore, participants� ratings of social desirability were positively associated with their level of depressive symptomatology and trait rumination. The aim of Study 4 was to conduct a pilot study to investigate the psychophysiological consequences of two further cognitive response styles: negative automatic thoughts and positive autobiographical recall. A series of twelve single-case (ABC-ABC) experiments were carried out using a procedure analogous to a clinical therapy process. Initially a depressed Story MIP was used to induce a depressed mood in participants (A). Participants were then required to respond to their depressed mood using negative self-statements (B), and positive autobiographical recall (C). Consistent with previous studies, zygomaticus major facial EMG and corrugator supercilii facial EMG clearly paralleled participants� mood reactivity throughout the experiment, whereas SCA and heart rate showed less consistent patterns of reactivity. This thesis has made an important contribution to mood and psychophysiological research by presenting the first in-depth investigation into the psychophysiological consequences of how people respond to depressed mood, from both a theoretical and a clinical perspective. It is anticipated that the findings of this research will bring about further investigation into the comparative efficacy of various brief mood-related cognitive intervention techniques, which will ultimately assist scientist-practitioners in selecting suitable brief cognitive intervention techniques for helping clients ameliorate their negative mood, emotional, and cognitive states.
152

The role and interaction of the AT₄ and cholinergic systems in the nucleus basalis of meynert (NBM) effects on spatial learning /

Wilson, Wendy L. January 2007 (has links) (PDF)
Thesis (Ph. D.)--Washington State University, December 2007. / Includes bibliographical references.
153

Cognitive control in human information processing

Smith, Philip. January 1984 (has links) (PDF)
Bibliography: leaves 388-403.
154

Numbers in the dark : early visual deprivation and the semantic numerical representation

Castronovo, Julie 06 April 2007 (has links)
Study of the impact of early visual deprivation and its following experience with numbers and numerosities on the elaboration of the semantic numerical representation with the same properties to those postulated in sighted people.
155

The effects of an acute bout of moderate intensity exercise on cognitive performance

Casebere, Molly C. January 1900 (has links) (PDF)
Thesis (M.S.)--University of North Carolina at Greensboro, 2006. / Title from PDF title page screen. Advisor: Jennifer Etnier; submitted to the School of Health and Human Performance. Includes bibliographical references (p. 37-43).
156

Numbers in the dark : early visual deprivation and the semantic numerical representation

Castronovo, Julie 06 April 2007 (has links)
Study of the impact of early visual deprivation and its following experience with numbers and numerosities on the elaboration of the semantic numerical representation with the same properties to those postulated in sighted people.
157

Mental Representations of Fractions: Development, Stable State, Learning Difficulties and Intervention. Représentations mentales des fractions : développement, état stable, difficultés d’apprentissage et intervention.

Gabriel, Florence 24 May 2011 (has links)
Fractions are very hard to learn. As the joke goes, “Three out of two people have trouble with fractions”. Yet the invention of a notation for fractions is very ancient, dating back to Babylonians and Egyptians. Moreover, it is thought that ratio representation is innate. And obviously, fractions are part of our everyday life. We read them in recipes, we need them to estimate distances on maps or rebates in shops. In addition, fractions play a key role in science and mathematics, in probabilities, proportions and algebraic reasoning. Then why is it so hard for pupils to understand and use them? What is so special about fractions? As in other areas of numerical cognition, a fast-developing field in cognitive science, we tackled this paradox through a multi-pronged approach, investigating both adults and children. Based on some recent research questions and intense debates in the literature, a first behavioural study examined the mental representations of the magnitude of fractions in educated adults. Behavioural observations from adults can indeed provide a first clue to explain the paradox raised by fractions. Contrary perhaps to most educated adults’ intuition, finding the value of a given fraction is not an easy operation. Fractions are complex symbols, and there is an on-going debate in the literature about how their magnitude (i.e. value) is processed. In a first study, we asked adult volunteers to decide as quickly as possible whether two fractions represent the same magnitude or not. Equivalent fractions (e.g. 1/4 and 2/8) were identified as representing the same number only about half of the time. In another experiment, adults were also asked to decide which of two fractions was larger. This paradigm offered different results, suggesting that participants relied on both the global magnitude of the fraction and the magnitude of the components. Our results showed that fraction processing depends on experimental conditions. Adults appear to use the global magnitude only in restricted circumstances, mostly with easy and familiar fractions. In another study, we investigated the development of the mental representations of the magnitude of fractions. Previous studies in adults showed that fraction processing can be either based on the magnitude of the numerators and denominators or based on the global magnitude of fractions and the magnitude of their components. The type of processing depends on experimental conditions. In this experiment, 5th, 6th, 7th-graders, and adults were tested with two paradigms. First, they performed a same/different task. Second, they carried out a numerical comparison task in which they had to decide which of two fractions was larger. Results showed that 5th-graders do not rely on the representations of the global magnitude of fractions in the Numerical Comparison task, but those representations develop from grade 6 until grade 7. In the Same/Different task, participants only relied on componential strategies. From grade 6 on, pupils apply the same heuristics as adults in fraction magnitude comparison tasks. Moreover, we have shown that correlations between global distance effect and children’s general fraction achievement were significant. Fractions are well known to represent a stumbling block for primary school children. In a third study, we tried to identify the difficulties encountered by primary school pupils. We observed that most 4th and 5th-graders had only a very limited notion of the meaning of fractions, basically referring to pieces of cakes or pizzas. The fraction as a notation for numbers appeared particularly hard to grasp. Building upon these results, we designed an intervention programme. The intervention “From Pies to Numbers” aimed at improving children’s understanding of fractions as numbers. The intervention was based on various games in which children had to estimate, compare, and combine fractions represented either symbolically or as figures. 20 game sessions distributed over 3 months led to 15-20% improvement in tests assessing children's capacity to estimate and compare fractions; conversely, children in the control group who received traditional lessons improved more in procedural skills such as simplification of fractions and arithmetic operations with fractions. Thus, a short classroom intervention inducing children to play with fractions improved their conceptual understanding. The results are discussed in light of recent research on the mental representation of the magnitude of fractions and educational theories. The importance of multidisciplinary approaches in psychology and education was also discussed. In sum, by combining behavioural experiments in adults and children, and intervention studies, we hoped to have improved the understanding how the brain processes mathematical symbols, while helping teachers get a better grasp of pupils’ difficulties and develop classroom activities that suit the needs of learners.
158

GABAergic systems in a model of age-related cognitive impairment

LaSarge, Candi Lynn 2011 May 1900 (has links)
With medical advancements extending the life span, age-related cognitive decline is a growing problem for the United States. A rat model of cognitive aging was used to investigate the GABAergic neurotransmitter system in relation to changes in learning and memory functions. Confocal stereology was used to determine the number of GABAergic and cholinergic projection neurons in the rostral basal forebrain of spatially characterized young and aged male F344 rats. The GABAergic system was then assessed as a potential target for improving age-related cognitive decline using an odor discrimination task sensitive to decline in aging. Performance of aged rats was impaired compared to young rats on the spatial version of the Morris water maze. Notably, a high degree of variability in individual abilities was observed among aged rats such that some aged rats performed on par with young (aged-unimpaired) and others performed outside the range of young, demonstrating impairment (aged-impaired). The number of basal forebrain neurons expressing multiple immunomarkers for GABAergic septohippocampal projection cells was selectively increased in aged-impaired rats in comparison to both young and aged-unimpaired rats. Indeed, among aged rats, worse performance in the water maze was reliably associated with higher GABAergic cell number. The number of cholinergic neurons, quantified in adjacent sections did not differ as a function of chronological age or cognitive status. These data suggest that aging can dysregulate GABAergic systems in circuitry important for learning and memory and such alterations may contribute to age-related cognitive decline. To test whether the GABAergic system may be a viable target for treating age-related cognitive decline, a second cohort of young and aged rats was characterized in an odor discrimination task. Similar to aged rat water maze performance, some aged rats performed odor learning discrimination problems on par with the young cohort (i.e. aged-unimpaired) and some aged rats were impaired compared to young (i.e. aged-impaired). Using a within-subjects design, the GABA(B) antagonist, CGP 55845 completely ameliorated odor discrimination learning deficits in aged-impaired rats in a dose-dependent manner. These data support the hypothesis that the GABAergic system should be a novel target for therapies aimed at treating age-related cognitive decline.
159

The Role of Estrogens in Cognition: Does Prophylactic Oophorectomy Affect Verbal, Spatial and Working Memory?

Schwartz, Deborah 11 January 2011 (has links)
Studies of non-human animals have shown that estrogens have a significant effect on the structure and neurochemistry of the brain and on cognitive behaviours. This study examines women with BRCA1/2 mutations who have undergone bilateral salpingo-oophorectomy (BSO), resulting in surgical menopause. In order to understand how the absence of endogenous estrogens affects cognition, women with BSO are compared to women with BRCA1/2 mutations but without BSO, as well as age-matched controls on tests of verbal, spatial and working memory. Women with BSO show decreased verbal memory and attention (logical memory) relative to controls but better performance on a measure of temporal lobe function (fluency clustering). Further, concentration of estrogen metabolites (E1G) negatively correlated with performance on a spatial memory task (object placement task) and with fluency clustering. These results indicate that endogenous estrogens are important for verbal memory and attention, but may contribute negatively to spatial memory and fluency clustering.
160

The Role of Estrogens in Cognition: Does Prophylactic Oophorectomy Affect Verbal, Spatial and Working Memory?

Schwartz, Deborah 11 January 2011 (has links)
Studies of non-human animals have shown that estrogens have a significant effect on the structure and neurochemistry of the brain and on cognitive behaviours. This study examines women with BRCA1/2 mutations who have undergone bilateral salpingo-oophorectomy (BSO), resulting in surgical menopause. In order to understand how the absence of endogenous estrogens affects cognition, women with BSO are compared to women with BRCA1/2 mutations but without BSO, as well as age-matched controls on tests of verbal, spatial and working memory. Women with BSO show decreased verbal memory and attention (logical memory) relative to controls but better performance on a measure of temporal lobe function (fluency clustering). Further, concentration of estrogen metabolites (E1G) negatively correlated with performance on a spatial memory task (object placement task) and with fluency clustering. These results indicate that endogenous estrogens are important for verbal memory and attention, but may contribute negatively to spatial memory and fluency clustering.

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