Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 36 for “"Brain volume"”.
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Genetic influence on brain volumes in psychosis.
… the genetic influence of susceptibility genes on brain volumes in psychosis. More specifically, I explored whether certain allelic variations are associated with global brain volumes in subjects with psychosis, their relatives and in healthy controls. To increase the statistical power, I combined …
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Analysing the evolution of brain size in three clades of carnivora using model selection
The evolution of brain size is a contentious topic, spawning numerous hypotheses on what drives it. In this study, we analyse and take several of them, and apply those theories to be tested on. We used a dataset by combining two forms of secondary data, the first on the brain sizes of various …
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A Model-Free Approach for Classification of fMRI Brain Images
… uses preprocessed time series for the whole brain volume. Using a training set of two groups of subjects the presented methodology identifies spatio-temporal features that distinguish the groups and uses these features to categorize new subjects. The methodology is illustrated using …
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The neural correlates of intimate partner violence in women
The hippocampus is more vulnerable than other brain structures to the neurotoxic effects of alcohol. It is reported that patients with chronic alcoholism have decreased brain weights and volumes. The hippocampal volume reductions in patients with chronic alcoholism have been found to be …
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Sequence-phase optimal (SPO) [d̳e̳l̳t̳a̳]B₀ field control for lipid suppression and homogeneity for brain magnetic resonance spectroscopic imaging
… to reduce lipid contamination and improve brain metabolite spectra in proton spectroscopic imaging. A rapidly reconfigurable 32-channel, local-multi-coil-shim-array is used to enhance lipid suppression and narrow metabolite linewidth in magnetic resonance spectroscopic imaging (MRSI) of the …
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Optimism and the brain: trait optimism mediates the protective role of orbitofrontal cortex gray matter volume against anxiety
… exist at both the personality level and the brain level that can influence anxiety as a general tendency. Trait optimism, characterized by the overall positive expectancy about the future, is positively correlated with emotional wellbeing and negatively correlated with anxiety. At the brain …
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Characterization of brain response following cranial radiotherapy
… a vital component for the treatment of pediatric brain tumors, with combination therapy that includes CRT resulting in almost 90\% five-year survival. However, survivors treated with CRT exhibit alterations in brain development and long-term deficits in brain structure and function. Clinical and …
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Development and characterization of methodology and technology for the alignment of fMRI time series
… time series. The algorithm assumes the human brain to be a rigid body and computes a head coordinate system on the basis of three reference points that lie on the directions correspondent to two of the eigenvectors of inertia of the volume, at the intersections with the head boundary. The …
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Genetic analysis of bipolar disorder and alcohol use disorder
… genomic technologies, bioinformatics, brain-imaging and environmental measures. An additional aim was to assess the genetic aetiology of BD-AUD comorbidity. Methods: For the genetic analysis underlying BD, a South African 'Afrikaner' family was investigated. Whole-genome sequencing …
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Substrates of social functioning in individuals with VCFS
… investigating the relationship between various brain structure volumes and social deficits in individuals with VCFS. Volumetric measures of brain regions based on magnetic resonance imaging (MRI) were compared between 6 VCFS individuals and 6 controls. Controls were identically matched according …
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Saliency Mapping in Convolutional Neural Networks to Determine Brain Age Trajectories
Brain Age (BA) estimation via Deep Learning has become a strong and reliable bio-marker for brain health, but the black-box nature of Neural Networks does not easily allow insight into the causal features of brain ageing. In this work, a ResNet model was trained as a BA regressor on T1 structural …
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Effects of environmental enrichment on personality traits in juvenile Arctic charr (Salvelinus alpinus) : interplay with brain morphology, growth performance and implication for welfare
… syndrome) as well as potential association with brain characteristics and growth for Arctic charr welfare implication. I found that physical environmental enrichment induces boldness consistency across long term period (Chapter 1), behavioural syndrome (Chapter 2), shyer individuals (Chapter 1), …
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Sarcopenia and cognitive ageing: investigating their interrelationship, biological correlates and the role of glucocorticoids
… technique to measure neck muscle size on volumetric MR brain scans; the subsequent use of the technique in elderly cohort studies; statistical modelling to investigate the role of glucocorticoids in sarcopenia; and an invasive clinical study to develop a novel technique to measure the …
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Reconstructing neurons from serial section electron microscopy images
… from a 3D electron microscopy (EM) image of a brain volume. A challenging and important subproblem is the segmentation of the image into neurons. For the past decade, convolutional networks have been used for 3D reconstruction of neurons from EM brain images. In this thesis, we develop a set of …
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Exploring the Cephalopod Brain: Towards Mapping the First Whole Brain Connectome and Whole Animal Projectome of a Pygmy Squid
… They possess large, highly centralised brains for processing sensory information, higher cognitive functioning, motor control, and feeding. Cephalopods are known for their ability to solve problems in unique ways, displaying idiosyncrasies in prey/predator behaviours, courtship and …
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Evolution Of Lactate Dehydrogenase Genes In Primates, With Special Consideration Of Nucleotide Organization In Mammalian Promoters
<p>Concomitant with an increase in brain volume and mass, the allocation of energetic resources to the brain increased during stem anthropoid evolution, leading to humans. One mechanism by which this allocation may have occurred is through greater use of lactate as a neuronal fuel. Both the …
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Neuroanatomical structural correlates of nonmotor symptoms in patients with movement disorders
… psychiatric extensive screening correlated with volume of brain region, are lacking. Thus, our present study aimed to extensively investigate cognitive functioning, psychiatric symptomatology and functional imagin of brain in PD patients presenting ICD, as compared with PD patients without ICD …
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Assessment and optimisation of MRI measures of atrophy as potential markers of disease progression in multiple sclerosis
… understand disease evolution. MRI measures of brain atrophy have been proposed for this purpose. This thesis investigates a number of measurement techniques to assess their relative ability to monitor disease progression in clinically isolated syndromes (CIS) and early relapsing remitting MS …
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The neurostructural effects of prenatal exposure to methamphetamine in an infant population in the Western Cape
… structures manually segmented with Freeview. Volumes were regressed with methamphetamine exposure (days/month of pregnancy) and related confounding variables, including total brain volume, gestational age at scan, exposure to cigarette smoking and infant sex. Diffusion data were processed with …
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The Effects of Lead Toxicity on Thyroid Hormone Physiology in the Developing Brains of Xenopus laevis Tadpoles
… proteins and how that affects the developing brain in Xenopus laevis tadpoles. Previous work has shown that Pb has the ability to dysregulate thyroid hormone (TH)-signaling in vertebrates and that Pb can impair brain development. This dissertation reports results for a series of Pb-treatment …
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