1,720,953 research outputs found
Improving Neurotechnologies for Chronic Pain through Brain-Computer Interfaces and Invasive Models of Human Cingulate Cortex Networks.
No full textChronic pain is a debilitating and intractable disease characterized by pathological changes to the nervous system. Specifically, chronic pain is associated with changes in neural circuitry, including maladaptive neuroplasticity, cortical reorganization, and changes to descending pain modulation pathways. Neurotechnologies, or technologies that interface with the nervous system, provide a therapeutic modality that can directly target the neuropathology underlying chronic pain. For example, brain-computer interfaces (BCIs) provide a promising avenue for therapeutic neural remodeling, specifically by leveraging neurofeedback to reinforce beneficial neural patterns. However, due to the variability of the functional and structural changes in the nervous system that contribute to chronic pain, BCIs have yet to be optimized to treat chronic pain. Further, our incomplete understanding of the cortical networks that underlie pain perception limits the design and translation of effective BCI systems. This dissertation addresses these challenges through three studies. The first study introduces a novel theta-controlled BCI system, which was tested in six chronic pain patients during an open-label pilot study. Through haptic and visual neurofeedback, the BCI was able to reinforce frontal theta in this study population over a six-week intervention. Patients increased their BCI performance, reflecting thought-driven control of neurofeedback, and showed a significant decrease in pain severity and pain interference scores without any adverse events. Pain relief significantly correlated with frontal theta modulation. These findings highlight the potential of BCI-mediated cortico-sensory coupling of frontal theta with vibrotactile stimulation for alleviating chronic pain. While frontal theta has been identified as an attractive pain-relief biomarker, the neurophysiology underlying this phenomenon is poorly understood, especially in the context of pain. We hypothesized that the source of these frontal theta features was the anterior cingulate cortex. To this end, our second study provides deeper insights into the contributions of activity from the human cingulate cortex (CC) and its networks to surface EEG features. Through invasive electrical stimulation of the subregions of the cingulate cortex and concurrent recording on surface EEG, we characterized the recruitment of CC networks through electrophysiological features captured on the scalp surface. We found that stimulation of the Midcingulate cortex produced distinct surface features in frontal regions, coinciding with our spatial targets during our first study. Further, we were able to characterize the temporal features of each CC subregion on scalp EEG. The final study provides a comprehensive profile of CC effective connectivity networks. The subregions of the CC are highly implicated in the perception of pain, yet precise relationships within its effective networks remain understudied. We mapped divergent effective networks of the anterior, mid, and posterior cingulate in 15 resection-free patients using single-pulse electrical stimulation, quantifying both cortico-cortical evoked potential (CCEP) magnitude and a morphology-based coherence metric, and profiling spatial, temporal, spectral, and inter-regional waveform features with machine learning. Coherence complemented magnitude, revealing hippocampal connections undetected by magnitude, and CC hub regions with equivalent connectivity to the anterior, midcingulate, and posterior subregions. Profiling the spatial distribution of effective networks confirmed that spatial patterns of effective connectivity coincide with distributions of CC white matter tractography. Inter-regional hierarchical clustering showed the midcingulate network had the most stereotyped CCEP morphology across regions. A Random Forest model trained to classify CC effective networks using features extracted from CCEPs reached 75% accuracy and revealed that assumption-based waveform features had the lowest predictive strength. These results provide a detailed, network-level account of human CC effective connectivity and highlight the utility of multimodal, feature-driven approaches over traditional assumption-based metrics. Together, these three studies present a novel BCI modality for treating chronic pain and elucidate neurophysiological mechanisms of pain perception networks critical for the improvement of future neurotechnologies
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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