Structural measures of the hippocampus have been linked to a variety of memory processes and also... more Structural measures of the hippocampus have been linked to a variety of memory processes and also to broader cognitive abilities. Gross volumetry has been widely used, yet the hippocampus has a complex formation, comprising distinct subfields which may be differentially sensitive to the deleterious effects of age, and to different aspects of cognitive performance. However, a comprehensive analysis of multidomain cognitive associations with hippocampal deformations among a large group of cognitively normal older adults is currently lacking. In 654 participants of the Lothian Birth Cohort 1936 (mean age = 72.5, SD = 0.71 years), we examined associations between the morphology of the hippocampus and a variety of memory tests (spatial span, letter-number sequencing, verbal recall, and digit backwards), as well as broader cognitive domains (latent measures of speed, fluid intelligence, and memory). Following correction for age, sex, and vascular risk factors, analysis of memory subtests ...
High, unabated glucocorticoid (GC) levels are thought to selectively damage certain tissue types.... more High, unabated glucocorticoid (GC) levels are thought to selectively damage certain tissue types. The hippocampus is thought to be particularly susceptible to such effects, and though findings from animal models and human patients provide some support for this hypothesis, evidence for associations between elevated GCs and lower hippocampal volumes in older age (when GC levels are at greater risk of dysregulation) is inconclusive. To address the possibility that the effects of GCs in non-pathological ageing may be too subtle for gross volumetry to reliably detect, we analyse associations between salivary cortisol (diurnal and reactive measures), hippocampal morphology and diffusion characteristics in 88 males, aged ∼73 years. However, our results provide only weak support for this hypothesis. Though nominally significant peaks in morphology were found in both hippocampi across all salivary cortisol measures (standardised β magnitudes<0.518, puncorrected>0.0000003), associations...
Journal of clinical neurology (Seoul, Korea), Jan 25, 2017
With the aim of facilitating the early detection of Alzheimer's disease, the Alzheimer's ... more With the aim of facilitating the early detection of Alzheimer's disease, the Alzheimer's Disease Neuroimaging Initiative proposed two stages based on the memory performance: early mild cognitive impairment (EMCI) and late mild cognitive impairment (LMCI). The current study was designed to investigate structural differences in terms of surface atrophy and microstructural changes of the hippocampus in EMCI and LMCI. Hippocampal shape modeling based on progressive template surface deformation was performed on T1-weighted MRI images obtained from 20 cognitive normal (CN) subjects, 17 EMCI patients, and 20 LMCI patients. A template surface in CN was used as a region of interest for diffusion-tensor imaging (DTI) voxel-based morphometry (VBM) analysis. Cluster-wise group comparison was performed based on DTI indices within the hippocampus. Linear regression was performed to identify correlations between DTI metrics and clinical scores. The hippocampal surface analysis showed signi...
The paradigm in biology is currently changing from that of conducting hypothesis-driven individua... more The paradigm in biology is currently changing from that of conducting hypothesis-driven individual experiments to that of utilizing the results of a massive data analysis with appropriate computational tools. We present LayMap, an implemented visualization system that helps the user to deal with a high volume of the biomedical literatu re such as MEDLINE, through the layered maps that are
Studies in Health Technology and Informatics, Feb 1, 1998
We present a new paradigm which incorporates multiple sets of tagged MRI data (MRI-SPAMM) acquire... more We present a new paradigm which incorporates multiple sets of tagged MRI data (MRI-SPAMM) acquired in a cascaded fashion in order to estimate the full 3-D motion of the left ventricle (LV) during its entire cardiac cycle. Our technique is based on the extension of the volumetric physics-based deformable models, whose parameters are functions, which can capture the local shape variation of an object with a small number of intuitive parameters. By integrating a cascaded sequence of SPAMM data sets into our modeling technique, we have extended the capability of MRI-SPAMM and have provided an accurate representation of the LV motion from end-diastole to end-diastole to better understand cardiac mechanics.
ABSTRACT In order to manage sustainable coastal development, it is essential to identify the caus... more ABSTRACT In order to manage sustainable coastal development, it is essential to identify the causal relationships among observation parameters that reveal the changes in the marine environment in a quantitative manner. On the Saemangeum coast, a land reclamation project by constructing sea dike has been underway since 1991. To monitor and assess the changes in the marine environment due to the project, the states of the ocean&#39;s physics and circulation, water quality, marine geology, and the marine ecosystem have been measured through the integrated ocean observation networks. In this paper, the observed data are statistically investigated with regard to observed and latent variables, in order to identify their causal relationships and compute the degrees of their influence. We performed a multivariate statistical analysis using a structural equation model based on oceanographic theory using the monthly mean observed data. As a result, 15 principal components were extracted and the statistical model was obtained by estimating the standardized regression coefficients of the observed variables and the latent variables, as well as those between the latent variables. The statistical model was applied to both the inner reclaimed area and the outer sea area individually to verify the model quantitatively how well it explains the changes of marine environment due to the blocking of seawater exchange in the inner reclaimed area comparable to the outer sea area separated by the sea dike. Our results show that the proposed statistical approach is quite suitable for understanding phenomena in ocean science that occur causally by identifying theoretically-known causal relationships quantitatively. By predicting the various impacts on environmental changes in advance through the quantitative estimation of a statistic model, we can prepare appropriate countermeasures or alternatives for preserving and protecting the environment, whose vulnerability is an inevitable result of such development. In this respect, our study can be effectively utilized as a tool for coastal management, policy-making, and planning.
ABSTRACT In order to gain a full understanding of a biological process, we must be able to augmen... more ABSTRACT In order to gain a full understanding of a biological process, we must be able to augment the known molecular interactions with discovered knowledge. We believe that a visualization system works as a means for accomplishing this task, as it provides an intuitive base for necessary information, among others. However, reported implementations have further problems: (1) The size of the information is not only enormous, but also grows very fast, which makes scalability and elision essential properties [5]; (2) the available information is not only incomplete, but also unreliable; and (3) the usual information in the field, such as protein modification [2], is inherently complex, which makes it very difficult to make the resulting visualization intuitive enough for end users as well as field experts. We address all the problems above with a 3D visualization system. 2 BiopathwayBuilder The system has the following features. Visual objects: In order to represent the participating objects, we choose spheres for molecules and cones for interactions. More specifically, we choose two kind of spheres, one big for real molecules, and one small for interactions. This makes it easy to distinguish unmodified states of a given molecule from its modified states, as well as regular interactions from complex ones where a primary interaction makes further interactions with another molecule or yet another interaction. Directionality of interaction, such as stimulation and inhibition, is encoded by a cone with varying thickness. See Figure 1 for an example. Layout with a nested structure: We place related unit spheres on an invisible concentric circle, whose center is placed on the surface of an invisible half sphere along with other circles. Related unit spheres may be explicitly connected with a specific interaction, such as &#39;bind&#39;. These half spheres may in turn be placed on the surface of a larger half sphere, when their details are not of current concern. This nested structure makes it possible to maintain scene consistency even when some of the component spheres are missing or the perspective is constantly changing. Search and Highlight: Users can start from a specific molecule and search molecules that are connected to it with a particular interaction type. The highlight function provides a sequence of steps of interactions from or to selected molecules, which are selected through the search function or interactively by the user.
Structural measures of the hippocampus have been linked to a variety of memory processes and also... more Structural measures of the hippocampus have been linked to a variety of memory processes and also to broader cognitive abilities. Gross volumetry has been widely used, yet the hippocampus has a complex formation, comprising distinct subfields which may be differentially sensitive to the deleterious effects of age, and to different aspects of cognitive performance. However, a comprehensive analysis of multidomain cognitive associations with hippocampal deformations among a large group of cognitively normal older adults is currently lacking. In 654 participants of the Lothian Birth Cohort 1936 (mean age = 72.5, SD = 0.71 years), we examined associations between the morphology of the hippocampus and a variety of memory tests (spatial span, letter-number sequencing, verbal recall, and digit backwards), as well as broader cognitive domains (latent measures of speed, fluid intelligence, and memory). Following correction for age, sex, and vascular risk factors, analysis of memory subtests ...
High, unabated glucocorticoid (GC) levels are thought to selectively damage certain tissue types.... more High, unabated glucocorticoid (GC) levels are thought to selectively damage certain tissue types. The hippocampus is thought to be particularly susceptible to such effects, and though findings from animal models and human patients provide some support for this hypothesis, evidence for associations between elevated GCs and lower hippocampal volumes in older age (when GC levels are at greater risk of dysregulation) is inconclusive. To address the possibility that the effects of GCs in non-pathological ageing may be too subtle for gross volumetry to reliably detect, we analyse associations between salivary cortisol (diurnal and reactive measures), hippocampal morphology and diffusion characteristics in 88 males, aged ∼73 years. However, our results provide only weak support for this hypothesis. Though nominally significant peaks in morphology were found in both hippocampi across all salivary cortisol measures (standardised β magnitudes<0.518, puncorrected>0.0000003), associations...
Journal of clinical neurology (Seoul, Korea), Jan 25, 2017
With the aim of facilitating the early detection of Alzheimer's disease, the Alzheimer's ... more With the aim of facilitating the early detection of Alzheimer's disease, the Alzheimer's Disease Neuroimaging Initiative proposed two stages based on the memory performance: early mild cognitive impairment (EMCI) and late mild cognitive impairment (LMCI). The current study was designed to investigate structural differences in terms of surface atrophy and microstructural changes of the hippocampus in EMCI and LMCI. Hippocampal shape modeling based on progressive template surface deformation was performed on T1-weighted MRI images obtained from 20 cognitive normal (CN) subjects, 17 EMCI patients, and 20 LMCI patients. A template surface in CN was used as a region of interest for diffusion-tensor imaging (DTI) voxel-based morphometry (VBM) analysis. Cluster-wise group comparison was performed based on DTI indices within the hippocampus. Linear regression was performed to identify correlations between DTI metrics and clinical scores. The hippocampal surface analysis showed signi...
The paradigm in biology is currently changing from that of conducting hypothesis-driven individua... more The paradigm in biology is currently changing from that of conducting hypothesis-driven individual experiments to that of utilizing the results of a massive data analysis with appropriate computational tools. We present LayMap, an implemented visualization system that helps the user to deal with a high volume of the biomedical literatu re such as MEDLINE, through the layered maps that are
Studies in Health Technology and Informatics, Feb 1, 1998
We present a new paradigm which incorporates multiple sets of tagged MRI data (MRI-SPAMM) acquire... more We present a new paradigm which incorporates multiple sets of tagged MRI data (MRI-SPAMM) acquired in a cascaded fashion in order to estimate the full 3-D motion of the left ventricle (LV) during its entire cardiac cycle. Our technique is based on the extension of the volumetric physics-based deformable models, whose parameters are functions, which can capture the local shape variation of an object with a small number of intuitive parameters. By integrating a cascaded sequence of SPAMM data sets into our modeling technique, we have extended the capability of MRI-SPAMM and have provided an accurate representation of the LV motion from end-diastole to end-diastole to better understand cardiac mechanics.
ABSTRACT In order to manage sustainable coastal development, it is essential to identify the caus... more ABSTRACT In order to manage sustainable coastal development, it is essential to identify the causal relationships among observation parameters that reveal the changes in the marine environment in a quantitative manner. On the Saemangeum coast, a land reclamation project by constructing sea dike has been underway since 1991. To monitor and assess the changes in the marine environment due to the project, the states of the ocean&#39;s physics and circulation, water quality, marine geology, and the marine ecosystem have been measured through the integrated ocean observation networks. In this paper, the observed data are statistically investigated with regard to observed and latent variables, in order to identify their causal relationships and compute the degrees of their influence. We performed a multivariate statistical analysis using a structural equation model based on oceanographic theory using the monthly mean observed data. As a result, 15 principal components were extracted and the statistical model was obtained by estimating the standardized regression coefficients of the observed variables and the latent variables, as well as those between the latent variables. The statistical model was applied to both the inner reclaimed area and the outer sea area individually to verify the model quantitatively how well it explains the changes of marine environment due to the blocking of seawater exchange in the inner reclaimed area comparable to the outer sea area separated by the sea dike. Our results show that the proposed statistical approach is quite suitable for understanding phenomena in ocean science that occur causally by identifying theoretically-known causal relationships quantitatively. By predicting the various impacts on environmental changes in advance through the quantitative estimation of a statistic model, we can prepare appropriate countermeasures or alternatives for preserving and protecting the environment, whose vulnerability is an inevitable result of such development. In this respect, our study can be effectively utilized as a tool for coastal management, policy-making, and planning.
ABSTRACT In order to gain a full understanding of a biological process, we must be able to augmen... more ABSTRACT In order to gain a full understanding of a biological process, we must be able to augment the known molecular interactions with discovered knowledge. We believe that a visualization system works as a means for accomplishing this task, as it provides an intuitive base for necessary information, among others. However, reported implementations have further problems: (1) The size of the information is not only enormous, but also grows very fast, which makes scalability and elision essential properties [5]; (2) the available information is not only incomplete, but also unreliable; and (3) the usual information in the field, such as protein modification [2], is inherently complex, which makes it very difficult to make the resulting visualization intuitive enough for end users as well as field experts. We address all the problems above with a 3D visualization system. 2 BiopathwayBuilder The system has the following features. Visual objects: In order to represent the participating objects, we choose spheres for molecules and cones for interactions. More specifically, we choose two kind of spheres, one big for real molecules, and one small for interactions. This makes it easy to distinguish unmodified states of a given molecule from its modified states, as well as regular interactions from complex ones where a primary interaction makes further interactions with another molecule or yet another interaction. Directionality of interaction, such as stimulation and inhibition, is encoded by a cone with varying thickness. See Figure 1 for an example. Layout with a nested structure: We place related unit spheres on an invisible concentric circle, whose center is placed on the surface of an invisible half sphere along with other circles. Related unit spheres may be explicitly connected with a specific interaction, such as &#39;bind&#39;. These half spheres may in turn be placed on the surface of a larger half sphere, when their details are not of current concern. This nested structure makes it possible to maintain scene consistency even when some of the component spheres are missing or the perspective is constantly changing. Search and Highlight: Users can start from a specific molecule and search molecules that are connected to it with a particular interaction type. The highlight function provides a sequence of steps of interactions from or to selected molecules, which are selected through the search function or interactively by the user.
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