Cortical network for gaze control in humans revealed using multimodal MRI

Functional magnetic resonance imaging (fMRI) techniques allow definition of cortical nodes that are presumed to be components of large-scale distributed brain networks involved in cognitive processes. However, very few investigations examine whether such functionally defined areas are in fact structurally connected. Here, we used combined fMRI and diffusion MRI-based tractography to define the cortical network involved in saccadic eye movement control in humans. The results of this multimodal imaging approach demonstrate white matter pathways connecting the frontal eye fields and supplementary eye fields, consistent with the known connectivity of these regions in macaque monkeys. Importantly, however, these connections appeared to be more prominent in the right hemisphere of humans. In addition, there was evidence of a dorsal frontoparietal pathway connecting the frontal eye field and the inferior parietal lobe, also right hemisphere dominant, consistent with specialization of the right hemisphere for directed attention in humans. These findings demonstrate the utility and potential of using multimodal imaging techniques to define large-scale distributed brain networks, including those that demonstrate known hemispheric asymmetries in humans

Investigation of smoothness-increasing accuracy-conserving filters for improving streamline integration through discontinuous fields

Journal ArticleStreamline integration of fields produced by computational fluid mechanics simulations is a commonly used tool for the investigation and analysis of fluid flow phenomena. Integration is often accomplished through the application of ordinary differential equation (ODE) integrators - integrators whose error characteristics are predicated on the smoothness of the field through which the streamline is being integrated, which is not available at the interelement level of finite volume and finite element data. Adaptive error control techniques are often used to ameliorate the challenge posed by interelement discontinuities

Cortical Network for Gaze Control in Humans Revealed Using Multimodal MRI

Functional magnetic resonance imaging (fMRI) techniques allow definition of cortical nodes that are presumed to be components of large-scale distributed brain networks involved in cognitive processes. However, very few investigations examine whether such functionally defined areas are in fact structurally connected. Here, we used combined fMRI and diffusion MRI-based tractography to define the cortical network involved in saccadic eye movement control in humans. The results of this multimodal imaging approach demonstrate white matter pathways connecting the frontal eye fields and supplementary eye fields, consistent with the known connectivity of these regions in macaque monkeys. Importantly, however, these connections appeared to be more prominent in the right hemisphere of humans. In addition, there was evidence of a dorsal frontoparietal pathway connecting the frontal eye field and the inferior parietal lobe, also right hemisphere dominant, consistent with specialization of the right hemisphere for directed attention in humans. These findings demonstrate the utility and potential of using multimodal imaging techniques to define large-scale distributed brain networks, including those that demonstrate known hemispheric asymmetries in human

Abnormal Brain Connectivity in the Primary Visual Pathway in Human Albinism

In albinism, the ipsilateral projection of retinal axons is significantly reduced, and most fibres project contralaterally. The retina and optic chiasm have been proposed as sites for misrouting. The number of lateral geniculate nucleus (LGN) relay neurons has been linked to LGN volume, suggesting a correlation between LGN size and the number of tracts traveling through the optic radiation (OR) to the primary visual cortex (V1). Using diffusion data and both deterministic and probabilistic tractography, we studied differences in OR between albinism and controls. Statistical analyses measured white matter integrity in areas corresponding to the OR, as well as LGN to V1 connectivity. Results revealed reduced white matter integrity and connectivity in the OR region in albinism compared to controls, suggesting altered structural development. Previous reports of smaller LGN and the altered thalamo-cortical connectivity reported here demonstrate the effect of misrouting on structural organization of the visual pathway in albinism

Ornamental Hallucination

Ornamental Hallucination proposes to reconstruct a polyphony of ancient Pagan symbols as feminist archetypes to disrupt hegemonic narratives. With the potential to transform reality it pronounces the importance that art has to reinstate the values of creativity and the imagination, envisioning new ways of looking at ourselves in the world, and the possibility for change. It outlines the power obsessed play of mass culture’s construction of manufactured consent by the barrage of twenty-four hours per day of advertising, news media and entertainment. Asserting that the ideas on the psychedelic experience, which sprang from the counter-culture of ‘the 1960’s’ is one way to liberate the mind from the trappings of hegemonic thinking. It claims that as artists are on the periphery of society, it is unlike any other discipline and therefore able to take on absurd theories as a way of critiquing the machinations of established thought. Ornamental Hallucination examines the revival of the feminine principle through a psychedelic framework that links us to nature, or as McKenna says, to Gaian consciousness, via ancient shamanic practices and the invention and construction of positive and mythically empowered feminine role models as a guide for the soul, breaking down binary thinking and reconnecting psychically to our ancestry, to our bodies and lived and shared experience. Using examples of my work, I trace a lineage with other feminist artists, linking them to the theme of the archaic revival. Pagan feminine symbols are interpreted for a contemporary lexicon placing art in ritualistic context and appointing it the role of historical corrective to the ills of cultural engineering. Ornamental Hallucination in its physiological dimension will comprise of four large freestanding ceramic sculptures, one candelabra wall piece, a wall painting and a performance with a costume made from ceramic, found objects, textile and cow horn. All ceramics are fired and painted in oil

Rhetorics of Opacity, Social Change, and Communal Cultivation: Case Studies of GLBTQ Christian Advocacy During the 1960s and Early 1970s

This dissertation probes questions about community and advocacy, analyzing four case studies involving GLBTQ Christian advocacy from the early 1960s to the early 1970s. Each case study involves the use of rhetoric to hide or downplay markers of the at-the-time stigmatized “homosexual” identity. The examined case studies are Bayard Rustin’s advocacy work with the Southern Christian Leadership Conference, the Council on Religion and the Homosexual, William Johnson’s ordination paper, and the 1973 Christian Reformed Church’s study report. To engage these texts, the dissertation develops theories about and methods for examining rhetorics of opacity—silence, hidden appeals, discourse that obscures, rhetorics of minimalization, and distraction. I argue that rhetorics of opacity can constitute powerful, yet complex and precarious, appeals that enable political and shared action, cultivate and constitute community, and foster social change and inclusion. This conceptualization offers rhetorical scholarship a fuller appreciation of the ways in which opacity and self-silencing comprise critical rhetorical strategies in campaigns for social change. Especially in treacherous, oppressive, and deadly social contexts and environments, the utilization of opaque rhetorics might constitute a viable strategy for advocates seeking transformation and communal empowerment while minimizing the risk that harm will befall on them for trying to foster change

Comparative Uncertainty Visualization for High-Level Analysis of Scalar- and Vector-Valued Ensembles

With this thesis, I contribute to the research field of uncertainty visualization, considering parameter dependencies in multi valued fields and the uncertainty of automated data analysis. Like uncertainty visualization in general, both of these fields are becoming more and more important due to increasing computational power, growing importance and availability of complex models and collected data, and progress in artificial intelligence. I contribute in the following application areas: Uncertain Topology of Scalar Field Ensembles. The generalization of topology-based visualizations to multi valued data involves many challenges. An example is the comparative visualization of multiple contour trees, complicated by the random nature of prevalent contour tree layout algorithms. I present a novel approach for the comparative visualization of contour trees - the Fuzzy Contour Tree. Uncertain Topological Features in Time-Dependent Scalar Fields. Tracking features in time-dependent scalar fields is an active field of research, where most approaches rely on the comparison of consecutive time steps. I created a more holistic visualization for time-varying scalar field topology by adapting Fuzzy Contour Trees to the time-dependent setting. Uncertain Trajectories in Vector Field Ensembles. Visitation maps are an intuitive and well-known visualization of uncertain trajectories in vector field ensembles. For large ensembles, visitation maps are not applicable, or only with extensive time requirements. I developed Visitation Graphs, a new representation and data reduction method for vector field ensembles that can be calculated in situ and is an optimal basis for the efficient generation of visitation maps. This is accomplished by bringing forward calculation times to the pre-processing. Visually Supported Anomaly Detection in Cyber Security. Numerous cyber attacks and the increasing complexity of networks and their protection necessitate the application of automated data analysis in cyber security. Due to uncertainty in automated anomaly detection, the results need to be communicated to analysts to ensure appropriate reactions. I introduce a visualization system combining device readings and anomaly detection results: the Security in Process System. To further support analysts I developed an application agnostic framework that supports the integration of knowledge assistance and applied it to the Security in Process System. I present this Knowledge Rocks Framework, its application and the results of evaluations for both, the original and the knowledge assisted Security in Process System. For all presented systems, I provide implementation details, illustrations and applications

The State of the Art of Spatial Interfaces for 3D Visualization

International audienceWe survey the state of the art of spatial interfaces for 3D visualization. Interaction techniques are crucial to data visualization processes and the visualization research community has been calling for more research on interaction for years. Yet, research papers focusing on interaction techniques, in particular for 3D visualization purposes, are not always published in visualization venues, sometimes making it challenging to synthesize the latest interaction and visualization results. We therefore introduce a taxonomy of interaction technique for 3D visualization. The taxonomy is organized along two axes: the primary source of input on the one hand and the visualization task they support on the other hand. Surveying the state of the art allows us to highlight specific challenges and missed opportunities for research in 3D visualization. In particular, we call for additional research in: (1) controlling 3D visualization widgets to help scientists better understand their data, (2) 3D interaction techniques for dissemination, which are under-explored yet show great promise for helping museum and science centers in their mission to share recent knowledge, and (3) developing new measures that move beyond traditional time and errors metrics for evaluating visualizations that include spatial interaction