Real-Time MEG Source Localization Using Regional Clustering

With its millisecond temporal resolution, Magnetoencephalography (MEG) is well suited for real-time monitoring of brain activity. Real-time feedback allows the adaption of the experiment to the subject’s reaction and increases time efficiency by shortening acquisition and off-line analysis. Two formidable challenges exist in real-time analysis: the low signal-to-noise ratio (SNR) and the limited time available for computations. Since the low SNR reduces the number of distinguishable sources, we propose an approach which downsizes the source space based on a cortical atlas and allows to discern the sources in the presence of noise. Each cortical region is represented by a small set of dipoles, which is obtained by a clustering algorithm. Using this approach, we adapted dynamic statistical parametric mapping for real-time source localization. In terms of point spread and crosstalk between regions the proposed clustering technique performs better than selecting spatially evenly distributed dipoles. We conducted real-time source localization on MEG data from an auditory experiment. The results demonstrate that the proposed real-time method localizes sources reliably in the superior temporal gyrus. We conclude that real-time source estimation based on MEG is a feasible, useful addition to the standard on-line processing methods, and enables feedback based on neural activity during the measurements.Deutsche Forschungsgemeinschaft (grant Ba 4858/1-1)National Institutes of Health (U.S.) (grants 5R01EB009048 and 2P41EB015896)Universitätsschule Jena (J21)German Academic Exchange Servic

Mne-X: MEG/EEG real-time acquisition, real-time processing, and real-time source localization framework

Providing millisecond-temporal resolution for non-invasive mapping of human brain functions, Magneto-/Electroencephalography (MEG/EEG) is predestined to monitor brain activity in real-time. While data analysis to date is mostly done subsequent to the acquistion process we introduce here an acquisition and real-time analysis application. Online feedback allows the adaption of the experiment to the subject’s reaction creating a whole set of new options and increasing time efficiency by shortening acquisition and offline analysis. To build a standalone application, we first designed MNE-CPP a cross-platform open source Qt5 C++ library, which implements the validated parts of our scripting toolboxes MNE-Python/MATLAB. Based on MNE-CPP we built MNE-X, which allows realtime acquisition, processing, and source localization

Effect of Nuclear Quadrupole Interaction on the Relaxation in Amorphous Solids

Recently it has been experimentally demonstrated that certain glasses display an unexpected magnetic field dependence of the dielectric constant. In particular, the echo technique experiments have shown that the echo amplitude depends on the magnetic field. The analysis of these experiments results in the conclusion that the effect seems to be related to the nuclear degrees of freedom of tunneling systems. The interactions of a nuclear quadrupole electrical moment with the crystal field and of a nuclear magnetic moment with magnetic field transform the two-level tunneling systems inherent in amorphous dielectrics into many-level tunneling systems. The fact that these features show up at temperatures $T<100mK$, where the properties of amorphous materials are governed by the long-range $R^{-3}$ interaction between tunneling systems, suggests that this interaction is responsible for the magnetic field dependent relaxation. We have developed a theory of many-body relaxation in an ensemble of interacting many-level tunneling systems and show that the relaxation rate is controlled by the magnetic field. The results obtained correlate with the available experimental data. Our approach strongly supports the idea that the nuclear quadrupole interaction is just the key for understanding the unusual behavior of glasses in a magnetic field.Comment: 18 pages, 9 figure

A enfermeira no contexto das práticas de gestão: desafios e perspectivas em um hospital de belo horizonte, minas gerais, Brasil

Se trata de un estudio cualitativo realizado en un gran hospital filantrópico de Belo Horizonte durante su proceso de reorganización administrativa. Los sujetos de investigación fueron diez enfermeras con cargo de gerente. Los datos se obtuvieron mediante entrevistas semiestructuradas, observación y análisis de documentos. Con el material recogido se interpretó la realidad objetiva, obtenida a través de la organización y análisis de los datos y, posteriormente, se establecieron las categorías empíricas del estudio relacionadas con la vivencia de la función de gestión de la enfermera. Las categorías son: “El trabajo de los gerentes”, “Nuevo significado a las prácticas de gestión” y “Factores que intervienen en el trabajo de los gerentes.” El trabajo de los gerentes se caracteriza por la administración de los recursos financieros, físicos y materiales, del cuerpo social que constituye la organización e incluye intermediación de relaciones internas y externas del hospital. La gestión de las enfermeras tiene un nuevo significado, carácter innovador en las prácticas de gestión, cuya relevancia social queda explícita. Respecto a los factores que intervienen en sus tareas, los gerentes destacan la formación profesional como un determinante para asumir cargos de gestión y el SUS (Sistema Único de Salud) que, en algunos casos, es un obstáculo en el crecimiento y desarrollo del hospital.ABSTRACT: This is a study of a qualitative nature, accomplished at a great case load philanthropic hospital in the administrative reorganization process. Ten nurses who occupied the position of manager were subject of the investigation. The data were obtained through the semi-structured interview, simple observation and documental analysis. The material obtained made the interpretation of the reality aimed at possible and it was obtained through the organization and analysis of the data and, later, the empiric categories of the study related to the existence of the managerial function by the nurse, which consists of: “the managers' work”, “attributing a new meaning to the managerial practices” and “intervening factors in the managers' work.” We observed that the managers' work is characterized by the administration of the financial, physical and material resources, of the social body that makes up the organization; it involves the internal and external mediation relationships peculiar to the hospital environment There is a new angle to the meaning of t management regarding nurses, attributing an innovative character to the managerial practices, social relevance being explicit in the referred practices. Regarding the intervening factors in their work, the managers detach the professional formation as a determinant for taking up managerial positions and the unique SUS (a streamline health system), which, in some situations, hinders the growth and the development of the hospital.RESUMO: Trata-se de um estudo de natureza qualitativa, realizado em um hospital filantrópico de grande porte em processo de reorganização administrativa. Foram sujeitas da investigação 10 enfermeiras que ocupavam o cargo de gerentes. Os dados foram obtidos mediante a realização de entrevista semi-estruturada, observação simples e a análise documental. O material obtido possibilitou a interpretação da realidade objetiva, a qual foi obtida por meio da organização e análise dos dados e, posteriormente, as categorias empíricas do estudo relacionadas à vivência da função gerencial pela enfermeira, quais sejam: “o trabalho das gerentes”, “atribuindo um novo significado às práticas gerenciais” e “fatores intervenientes no trabalho das gerentes.” Observou-se que o trabalho das gerentes é caracterizado pelo gerenciamento de recursos financeiros, materiais, físicos e do corpo social que integra a organização, envolve a intermediação de relações internas e externas ao ambiente hospitalar. Há uma ressignificação da gerência pelas enfermeiras, atribuindo um caráter inovador às práticas gerenciais, ficando explícita a relevância social das referidas práticas. Quanto aos fatores intervenientes no seu trabalho, as gerentes destacam a formação profissional como um determinante para assumirem cargos gerenciais e o Sistema Único de Saúde, o qual, em algumas situações, dificulta o crescimento e o desenvolvimento do hospital

La enfermera en el contexto de las prácticas de administración: retos y perspectivas en un hospital de belo horizonte, minas gerais - brasil

Se trata de un estudio cualitativo realizado en un gran hospital filantrópico de Belo Horizonte durante su proceso de reorganización administrativa. Los sujetos de investigación fueron diez enfermeras con cargo de gerente. Los datos se obtuvieron mediante entrevistas semi-estructuradas, observación y análisis de documentos. Con el material recogido se interpretó la realidad objetiva, obtenida a través de la organización y análisis de los datos y, posteriormente, se establecieron las categorías empíricas del estudio relacionadas con la vivencia de la función de gestión de la enfermera. Las categorías son: ¿El trabajo de los gerentes¿, ¿Nuevo significado a las prácticas de gestión¿ y ¿Factores que intervienen en el trabajo de los gerentes.¿ El trabajo de los gerentes se caracteriza por la administración de los recursos financieros, físicos y materiales, del cuerpo social que constituye la organización e incluye intermediación de relaciones internas y externas del hospital. La gestión de las enfermeras tiene un nuevo significado, carácter innovador en las prácticas de gestión, cuya relevancia social queda explícita. Respecto a los factores que intervienen en sus tareas, los gerentes destacan la formación profesional como un determinante para asumir cargos de gestión y el SUS (Sistema Único de Salud) que, en algunos casos, es un obstáculo en el crecimiento y desarrollo del hospita

Emotional processing in Parkinson's disease and anxiety: an EEG study of visual affective word processing

A general problem in the design of an EEG-BCI system is the poor quality and low robustness of the extracted features, affecting overall performance. However, BCI systems that are applicable in real-time and outside clinical settings require high performance. Therefore, we have to improve the current methods for feature extraction. In this work, we investigated EEG source reconstruction techniques to enhance the extracted features based on a linearly constrained minimum variance (LCMV) beamformer. Beamformers allow for easy incorporation of anatomical data and are applicable in real-time. A 32-channel EEG-BCI system was designed for a two-class motor imagery (MI) paradigm. We optimized a synchronous system for two untrained subjects and investigated two aspects. First, we investigated the effect of using beamformers calculated on the basis of three different head models: a template 3-layered boundary element method (BEM) head model, a 3-layered personalized BEM head model and a personalized 5-layered finite difference method (FDM) head model including white and gray matter, CSF, scalp and skull tissue. Second, we investigated the influence of how the regions of interest, areas of expected MI activity, were constructed. On the one hand, they were chosen around electrodes C3 and C4, as hand MI activity theoretically is expected here. On the other hand, they were constructed based on the actual activated regions identified by an fMRI scan. Subsequently, an asynchronous system was derived for one of the subjects and an optimal balance between speed and accuracy was found. Lastly, a real-time application was made. These systems were evaluated by their accuracy, defined as the percentage of correct left and right classifications. From the real-time application, the information transfer rate (ITR) was also determined. An accuracy of 86.60 ± 4.40% was achieved for subject 1 and 78.71 ± 0.73% for subject 2. This gives an average accuracy of 82.66 ± 2.57%. We found that the use of a personalized FDM model improved the accuracy of the system, on average 24.22% with respect to the template BEM model and on average 5.15% with respect to the personalized BEM model. Including fMRI spatial priors did not improve accuracy. Personal fine- tuning largely resolved the robustness problems arising due to the differences in head geometry and neurophysiology between subjects. A real-time average accuracy of 64.26% was reached and the maximum ITR was 6.71 bits/min. We conclude that beamformers calculated with a personalized FDM model have great potential to ameliorate feature extraction and, as a consequence, to improve the performance of real-time BCI systems