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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.
21

Control and Management Strategy of Autonomous Vehicle Functions

Kim, Chang Won 2010 December 1900 (has links)
In this research, an autonomous vehicle function management methodology is studied. In accordance with the traffic situation, the decision making level chooses the optimal function that guarantees safety and minimizes fuel consumption while the control level is implemented via neuromorphic strategy based on the brain limbic system. To realize the decision making strategy, the Analytic Hierarchy Process (AHP) is used by considering driving safety, driving speed, and fuel efficiency as the objectives. According to the traffic situation and predefined driving mode, Lane Change Maneuver (LCM) and Adaptive Cruise Control (ACC) are chosen as the alternative functions in the AHP framework. The adaptive AHP is utilized to cope with dynamically changing traffic environment. The proposed adaptive AHP algorithm provides an optimal relative importance matrix that is essential to make decisions under a varying traffic situation and driving modes. The simulation results show that proposed autonomous vehicle function management structure produces optimal decisions that satisfy the driving preference. The stability of BLS based control is also investigated via Cell-to-Cell Mapping. In this research, autonomous vehicle functions such as Lane change maneuver and Adaptive cruise control are developed by means of BLS based control. The simulation results considered various traffic situations that an autonomous vehicle can encounter. To demonstrate the suggested control method Cell-to-Cell Mapping is utilized. Subsequently, the autonomous vehicle function management strategy is developed by Applying AHP and an adaptive AHP strategy is developed to cope with various traffic situations and driving modes. The suggested method is verified numerical simulations.
22

Long-term consequences of perinatal high-fat feeding on dopamine function and metabolism in rats

Naef, Lindsay. January 2008 (has links)
This research project investigates the long-term consequences of perinatal exposure to high-fat (HF) on the mesocorticolimbic dopamine (DA) system. Adult offspring of mothers fed a HF diet (30% fat, compared to 5% in control mothers (C)) during the last week of gestation and throughout lactation displayed decreased locomotion in response to an acute amphetamine challenge and decreased behavioral sensitization to repeated amphetamine compared to C animals. These behavioral effects were accompanied by small increases in tyrosine hydroxylase expression in the ventral tegmental area and significant increases in DA and DOPAC content in the NAc, suggesting an elevated DA tone in this target field. In the NAc, there were no significant changes in D1, D2 receptors or DA transporter (DAT) levels between diet groups. The behavioural and biochemical data were collected in adulthood, long after the termination of the diet suggesting that a HF perinatal diet is inducing permanent changes within the DA system and might contribute to the development of metabolic disturbances.
23

The magnetic resonance imaging-based assessment of whole-brain structural integrity in temporal lobe epilepsy

Horwood, Linda. January 1900 (has links)
Thesis (M.Sc.). / Written for the Dept. of Neurology and Neurosurgery. Title from title page of PDF (viewed 2008/12/07). Includes bibliographical references.
24

Anti-epileptic effect of low frequency stimulation using the kindling model /

Carrington, Carys Alana. January 1900 (has links)
Thesis (M.Sc.) - Carleton University, 2005. / Includes bibliographical references (p. 110-116). Also available in electronic format on the Internet.
25

Cortico-limbic mechanisms of meaning making : judgments of personality and emotion from faces /

Bel-Bahar, Tarik Stanislaw. January 2008 (has links)
Thesis (Ph. D.)--University of Oregon, 2008. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 188-219). Also available online in ProQuest, free to University of Oregon users.
26

Neuro-imagerie fonctionnelle du circuit cortico-limbique lors du traitement émotionnel chez le patient schizophrène et le volontaire sain / Functional neuro-imaging of the cortico-limbic circuit during emotional processing in schizophrenia patients and healthy volunteers

Comte, Magali 18 December 2015 (has links)
Au sein du circuit cortico-limbique, des régions complémentaires seraient impliquées soit dans l’évaluation soit dans la régulation des états affectifs. Cependant, la contribution respective de ces mécanismes «bottom-up» et «top-down» lors du traitement émotionnel reste à clarifier. Premièrement, nous avons validé un nouveau paradigme d’IRMf conçu pour dissocier les composants du circuit cortico-limbique, c.-à-d. le circuit dorsal cognitif entrecroisé avec le circuit ventral affectif. Nous avons trouvé que l’amygdale et ses connexions avec le circuit dorsal étaient engagées par le traitement émotionnel bottom-up. Le cortex cingulaire antérieur (CCA) dorsal et ses connexions avec le cortex préfrontal dorso-latéral (CPFDL) et l’amygdale étaient recrutés par la résolution top-down du conflit émotionnel. Le CPFDL et ses connexions avec le CCA dorsal étaient engagés par le contrôle attentionnel top-down. Puis, nous avons examiné l’impact de l’anxiété sur le circuit. Nous avons montré qu’une forte anxiété était associée à une activation plus importante du CCA en réponse au conflit émotionnel mais à une connectivité réduite entre CCA et CPFL. Enfin, nous avons examiné la variation d’activité et de connectivité fonctionnelle chez des patients schizophrènes. Chez les patients comparativement aux témoins, les processus bottom-up étaient associés à une interaction réduite entre l’amygdale et le CCA ventral et dorsal ainsi que le CPFDL. La résolution du conflit émotionnel entraînait une plus forte connectivité entre CCA dorsal et CCA ventral ainsi que le CPFDL. L’augmentation du contrôle attentionnel provoquait une connectivité plus importante entre le CPFDL et le CCA ventral. / Within the cortico-limbic circuit, complementary regions are believed to be involved in either the appraisal or the regulation of affective state. However, the respective contribution of these bottom-up and top-down mechanisms during emotion processing remains to be clarified. First, we validated a new fMRI paradigm designed to dissociate the components of the cortico-limbic circuit, that is, the dorsal cognitive circuit intertwined with the ventral affective circuit. We found that the amygdala and its connections to the dorsal circuit was engaged by bottom-up emotional processing. The dorsal anterior cingulate cortex (ACC) and its connections to the dorsolateral prefrontal cortex (DLPFC) and amygdala, was recruited by top-down resolution of emotional conflict. The DLPFC and its connections to dorsal ACC was engaged by top-down attentional control. Secondly, we investigated the impact of anxiety on the circuit. We demonstrated that higher levels of anxiety were associated with stronger conflict-related activation in ACC but with reduced connectivity between ACC and LPFC. Finally, we examined the variation in functional activity and connectivity in schizophrenia patients. In patients compared to controls, bottom-up processes were associated with reduced functional interaction between the amygdala and both dorsal and ventral ACC as well as DLPFC. Top-down resolution of emotional conflict led to stronger functional connectivity between the dorsal ACC and both ventral parts of ACC and DLPFC. Increased top-down attentional control caused higher functional coupling between the DLPFC and ventral ACC.
27

Brain Aging: Uncovering Cortical Characteristics of Healthy Aging in Young Adults

Bajaj, Sahil, Alkozei, Anna, Dailey, Natalie S., Killgore, William D. S. 11 December 2017 (has links)
Despite extensive research in the field of aging neuroscience, it still remains unclear whether age related cortical changes can be detected in different functional networks of younger adults and whether these networks respond identically to healthy aging. We collected high-resolution brain anatomical data from 56 young healthy adults (mean age = 30.8 +/- 8.1 years, 29 males). We performed whole brain parcellation into seven functional networks, including visual, somatomotor, dorsal attention, ventral attention, limbic, frontoparietal and default mode networks. We estimated intracranial volume (ICV) and averaged cortical thickness (CT), cortical surface area (CSA) and cortical volume (CV) over each hemisphere as well as for each network. Averaged cortical measures over each hemisphere, especially CT and CV, were significantly lower in older individuals compared to younger ones (one-way ANOVA, p < 0.05, corrected for multiple comparisons). There were negative correlations between age and averaged CT and CV over each hemisphere (p < 0.05, corrected for multiple comparisons) as well as between age and ICV (p = 0.05). Network level analysis showed that age was negatively correlated with CT for all functional networks (p < 0.05, corrected for multiple comparisons), apart from the limbic network. While age was unrelated to CSA, it was negatively correlated with CV across several functional networks (p < 0.05, corrected for multiple comparisons). We also showed positive associations between CV and CT and between CV and CSA for all networks (p < 0.05, corrected for multiple comparisons). We interpret the lack of association between age and CT of the limbic network as evidence that the limbic system may be particularly resistant to age-related declines during this period of life, whereas the significant age-related declines in averaged CT over each hemisphere as well as in all other six networks suggests that CT may serve as a reliable biomarker to capture the effect of normal aging. Due to the simultaneous dependence of CV on CT and CSA, CV was unable to identify such effects of normal aging consistently for the other six networks, but there were negative associations observed between age and averaged CV over each hemisphere as well as between age and ICV. Our findings suggest that the identification of early cortical changes within various functional networks during normal aging might be useful for predicting the effect of aging on the efficiency of functional performance even during early adulthood.
28

Osteoporóza, klimakterický syndrom a výskyt symptomů temporolimbické dysfunkce / Osteoporosis, climacteric syndrome, and signs of the temporolimbic dysfunction

Capranicová, Aneta January 2017 (has links)
v anglickém jazyce Charles University in Prague Faculty of Pharmacy in Hradec Králové Department of Biological and Medical Sciences Author: Bc. Aneta Capranicová Title of diploma thesis: Osteoporosis, climacteric syndrome and signs of the temporolimbic dysfunction Objective of the thesis: The aim of the diploma thesis was to find out whether there will appear temporolimbic dysfunctions in women attending the osteoporotic clinic at the Faculty Hospital in Hradec Králové and compare their results with the results of a healthy population. Methods: Two standardized questionnaires - CSPI and LSCL-33 - were used to assess the occurrence of epileptic spectrum disorders. The Microsoft Office Excel was used to process the results. Results: It was found that the women population reaches score points corresponding to the healthy population. In the CSPI questionnaire, the average value was 7.6 and for the LSCL-33 5.5 points. From these results it can be assumed that osteoporosis and climacteric syndrome does not affect the occurrence of epileptic spectrum disorders. To confirm the results, I would recommend the study to be repeated in a group with a larger number of respondents. For comparison with gamblers or smokers, both groups show a higher incidence of epileptic spectrum disorders than the group of women...
29

Computational Framework for the Identification of Neural Circuits Underlying Psychiatric Disorders

Chang, Jonathan January 2021 (has links)
Autism spectrum disorders (ASDs) are characterized by phenotypic and genetic heterogeneity. Our analysis of functional networks perturbed in ASD suggests that both truncating and non-truncating de novo mutations contribute to autism. Moreover, we find that truncating mutations affecting the same exon lead to strikingly similar intellectual phenotypes in unrelated ASD probands and propose that exons, rather than genes, represent a unit of effective phenotypic impact for truncating mutations in autism. The phenotypic effects are likely mediated by nonsense-mediated decay of splicing isoforms and similar patterns may be observed in other genetic disorders. While multiple cell types and brain areas are affected, the impact of ASD mutations converge on a strongly interconnected system of neural structures that involve basal ganglia loops and the limbic system. We observe that distant projections constitute a disproportionately large fraction of the network composition, suggesting that the integration of diverse brain regions is a key property of the neural circuit. We demonstrate that individual de novo mutations impact several disparate components of the network and may further explain the phenotypic variability. Overall, our study presents a method that, to our knowledge, is the first unbiased approach using genetic variants to comprehensively discover and identify the neural circuitry affected in a psychiatric disorder.
30

Long-term consequences of perinatal high-fat feeding on dopamine function and metabolism in rats

Naef, Lindsay. January 2008 (has links)
No description available.

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