Localization of the Epileptogenic Zone Using High Frequency Oscillations

For patients with drug-resistant focal epilepsy, surgery is the therapy of choice in order to achieve seizure freedom. Epilepsy surgery foremost requires the identification of the epileptogenic zone (EZ), defined as the brain area indispensable for seizure generation. The current gold standard for identification of the EZ is the seizure-onset zone (SOZ). The fact, however that surgical outcomes are unfavorable in 40–50% of well-selected patients, suggests that the SOZ is a suboptimal biomarker of the EZ, and that new biomarkers resulting in better postsurgical outcomes are needed. Research of recent years suggested that high-frequency oscillations (HFOs) are a promising biomarker of the EZ, with a potential to improve surgical success in patients with drug-resistant epilepsy without the need to record seizures. Nonetheless, in order to establish HFOs as a clinical biomarker, the following issues need to be addressed. First, evidence on HFOs as a clinically relevant biomarker stems predominantly from retrospective assessments with visual marking, leading to problems of reproducibility and reliability. Prospective assessments of the use of HFOs for surgery planning using automatic detection of HFOs are needed in order to determine their clinical value. Second, disentangling physiologic from pathologic HFOs is still an unsolved issue. Considering the appearance and the topographic location of presumed physiologic HFOs could be immanent for the interpretation of HFO findings in a clinical context. Third, recording HFOs non-invasively via scalp electroencephalography (EEG) and magnetoencephalography (MEG) is highly desirable, as it would provide us with the possibility to translate the use of HFOs to the scalp in a large number of patients. This article reviews the literature regarding these three issues. The first part of the article focuses on the clinical value of invasively recorded HFOs in localizing the EZ, the detection of HFOs, as well as their separation from physiologic HFOs. The second part of the article focuses on the current state of the literature regarding non-invasively recorded HFOs with emphasis on findings and technical considerations regarding their localization

Aulas flexibles : un espacio de reflexión frente a la resignificación del lenguaje oral en los estudiantes de la I. E. Rafael J. Mejía para el empoderamiento de las competencias ciudadanas

RESUMEN: El trabajo de grado “Aulas flexibles: Un espacio de reflexión frente a la Resignificación del lenguaje oral en los estudiantes de la I.E Rafael J Mejía para el empoderamiento de las competencias ciudadanas” es una investigación cualitativa. La población estudiantil fue los niños y jóvenes estudiantes de las aulas flexibles en extraedad, esa condición de una u otra manera ha afectado su regularidad escolar, además “tienen comportamientos no adecuados” y muestran dificultades académicas. Esta problemática se asocia la mayor parte de las veces con un mal uso del lenguaje y con la dificultad para resolver diferentes situaciones problema, presentes en la cotidianidad y en las relaciones consigo mismo, con sus pares y el entorno. Esta situación nos llevó a plantear así algunas estrategias de solución a través de los talleres como estrategia y el interaccionismo simbólico como enfoque metodológico, en el trabajo se desarrollaron 6 talleres que permitieron resignificar el lenguaje oral, fortalecer y empoderarlos en las competencias ciudadanas, lo cual conllevó a mejorar sus relaciones sociales, consigo mismos y con el entorno. Para ello, se utilizó como enfoque metodológico el interaccionismo simbólico – como ya se dijo-; con el cual pretendimos suscitar en los estudiantes un proceso reflexivo y consciente que permitiera una mejor expresión y mejores formas comunicativas; maneras más tranquilas y positivas, generando así espacios de convivencia, tolerancia y paz. Es importante mencionar que la sistematización de este trabajo de profundización se ejecuta a través de la narrativa: “De las cavernas al jardín de los Orcos.ABSTRACT: The dissertation “Flexible classrooms: A place to reflect about resignification (to do another sense to words) of the oral language to the students from the I.E. Rafael J. Mejia to empower the civic competences” is a qualitative investigation. The population was the students from the flexible classrooms, who are children and teens older than the school-age. This condition has affected their school regularity, besides they have not an appropriated behavior and they have academic difficult. Mainly, this problematic is associated with a wrong use to the language and with a difficult to resolve different problematic situations that we live every day. They have problems in relation with themselves and problems to be in contact with other people and the environment. Is because of this problem that we created resolve-strategies through workshops like a strategic and the symbolic interactionism like a methodological approach. We develop 6 workshops who afford to do significance the oral language of the students to strengthen and improve their civic competences, these workshops allow to improve their social relations, with the environment and with themselves. To do the workshops we use the symbolic interactionism as the methodological approach, with this, we pretended provoke a reflexive and conscious process in the students to afford a better language expression and a better form of communication with an easier and positive way to communication, in order to create spaces with a social harmony, tolerance and peace. Is important to mention the deep systematization of this dissertation was executed through the narrative: “From de cavern to the garden of the Orcs

The impact of MEG source reconstruction method on source-space connectivity estimation: A comparison between minimum-norm solution and beamforming.

Despite numerous important contributions, the investigation of brain connectivity with magnetoencephalography (MEG) still faces multiple challenges. One critical aspect of source-level connectivity, largely overlooked in the literature, is the putative effect of the choice of the inverse method on the subsequent cortico-cortical coupling analysis. We set out to investigate the impact of three inverse methods on source coherence detection using simulated MEG data. To this end, thousands of randomly located pairs of sources were created. Several parameters were manipulated, including inter- and intra-source correlation strength, source size and spatial configuration. The simulated pairs of sources were then used to generate sensor-level MEG measurements at varying signal-to-noise ratios (SNR). Next, the source level power and coherence maps were calculated using three methods (a) L2-Minimum-Norm Estimate (MNE), (b) Linearly Constrained Minimum Variance (LCMV) beamforming, and (c) Dynamic Imaging of Coherent Sources (DICS) beamforming. The performances of the methods were evaluated using Receiver Operating Characteristic (ROC) curves. The results indicate that beamformers perform better than MNE for coherence reconstructions if the interacting cortical sources consist of point-like sources. On the other hand, MNE provides better connectivity estimation than beamformers, if the interacting sources are simulated as extended cortical patches, where each patch consists of dipoles with identical time series (high intra-patch coherence). However, the performance of the beamformers for interacting patches improves substantially if each patch of active cortex is simulated with only partly coherent time series (partial intra-patch coherence). These results demonstrate that the choice of the inverse method impacts the results of MEG source-space coherence analysis, and that the optimal choice of the inverse solution depends on the spatial and synchronization profile of the interacting cortical sources. The insights revealed here can guide method selection and help improve data interpretation regarding MEG connectivity estimation

Metro de Medellín, antecedentes y desarrollo

Metro is a well-known massive transportation organization in the Colombian Territory, specifically in the Aburra Valley. Its well deserved success is an achievement of 25 years of hard work in which It has generated great impacts among its users, socially, environmentally and economically. Although there were initial obstacles in this great project and they are not mentioned, it is worth mentioning that they were plenty, nonetheless, not enough as to avoid the achievement Of a successful company that has been growing year by year. With its philosophy known as “Metro Culture” it has managed to position itself among the hearts and minds of each one of the inhabitant and has developed o sense of belonging among these, which has taken the company to where it currently is.Metro es una reconocida organización de transporte masivo en el territorio colombiano, más específicamente en el Valle de Aburrá. Su merecido éxito es el logro de 25 años de arduo trabajo, en los cuales ha generado grandes impactos en sus usuarios, tanto en el ámbito social, como en el ambiental y el económico. Aunque los obstáculos iniciales de este gran proyecto no son muy mencionados, cabe resaltar que fueron bastantes, sin embargo, no los suficientes para evitar conseguir que esta empresa saliera a flote y progresara año tras año. Con su filosofía de vida ‘‘La cultura Metro’’ ha logrado posicionarse en el corazón de cada uno de los paisas y ha desarrollado un sentido de pertenencia en estos, que hoy en día lo catapultan a estar donde está

5to. Congreso Internacional de Ciencia, Tecnología e Innovación para la Sociedad. Memoria académica

El V Congreso Internacional de Ciencia, Tecnología e Innovación para la Sociedad, CITIS 2019, realizado del 6 al 8 de febrero de 2019 y organizado por la Universidad Politécnica Salesiana, ofreció a la comunidad académica nacional e internacional una plataforma de comunicación unificada, dirigida a cubrir los problemas teóricos y prácticos de mayor impacto en la sociedad moderna desde la ingeniería. En esta edición, dedicada a los 25 años de vida de la UPS, los ejes temáticos estuvieron relacionados con la aplicación de la ciencia, el desarrollo tecnológico y la innovación en cinco pilares fundamentales de nuestra sociedad: la industria, la movilidad, la sostenibilidad ambiental, la información y las telecomunicaciones. El comité científico estuvo conformado formado por 48 investigadores procedentes de diez países: España, Reino Unido, Italia, Bélgica, México, Venezuela, Colombia, Brasil, Estados Unidos y Ecuador. Fueron recibidas un centenar de contribuciones, de las cuales 39 fueron aprobadas en forma de ponencias y 15 en formato poster. Estas contribuciones fueron presentadas de forma oral ante toda la comunidad académica que se dio cita en el Congreso, quienes desde el aula magna, el auditorio y la sala de usos múltiples de la Universidad Politécnica Salesiana, cumplieron respetuosamente la responsabilidad de representar a toda la sociedad en la revisión, aceptación y validación del conocimiento nuevo que fue presentado en cada exposición por los investigadores. Paralelo a las sesiones técnicas, el Congreso contó con espacios de presentación de posters científicos y cinco workshops en temáticas de vanguardia que cautivaron la atención de nuestros docentes y estudiantes. También en el marco del evento se impartieron un total de ocho conferencias magistrales en temas tan actuales como la gestión del conocimiento en la universidad-ecosistema, los retos y oportunidades de la industria 4.0, los avances de la investigación básica y aplicada en mecatrónica para el estudio de robots de nueva generación, la optimización en ingeniería con técnicas multi-objetivo, el desarrollo de las redes avanzadas en Latinoamérica y los mundos, la contaminación del aire debido al tránsito vehicular, el radón y los riesgos que representa este gas radiactivo para la salud humana, entre otros

MEG connectivity and power detections with minimum norm estimates require different regularization parameters

Minimum Norm Estimation (MNE) is an inverse solution method widely used to reconstruct the source time series that underlie magnetoencephalography (MEG) data. MNE addresses the ill-posed nature of MEG source estimation through regularization (e.g., Tikhonov regularization). Selecting the best regularization parameter is a critical step. Generally, once set, it is common practice to keep the same coefficient throughout a study. However, it is yet to be known whether the optimal lambda for spectral power analysis of MEG source data coincides with the optimal regularization for source-level oscillatory coupling analysis. We addressed this question via extensive Monte-Carlo simulations of MEG data, where we generated 21,600 configurations of pairs of coupled sources with varying sizes, signal-to-noise ratio (SNR), and coupling strengths. Then, we searched for the Tikhonov regularization coefficients (lambda) that maximize detection performance for (a) power and (b) coherence. For coherence, the optimal lambda wastwo orders of magnitude smaller than the best lambda for power. Moreover, we found that the spatial extent of the interacting sources and SNR, but not the extent of coupling, were the main parameters affecting the best choice for lambda. Our findings suggest using less regularization when measuring oscillatory coupling compared to power estimation.Peer reviewe

Neural oscillations track natural but not artificial fast speech: Novel insights from speech-brain coupling using MEG

Convincing evidence for synchronization of cortical oscillations to normal rate speech and artificially accelerated speech has been offered. However, the case of natural speech rate variations, which are ubiquitous in everyday life, has been largely overlooked. Here, we directly compared changes in the properties of cortico-acoustic coupling when speech naturally shifts from normal to fast rate and when it is artificially accelerated. Neuromagnetic brain signals of 24 normal-hearing adults were recorded with magnetoencephalography (MEG) while they listened to natural normal (∼6 syllables/s), natural fast (∼9 syllables/s) and time-compressed (∼9 syllables/s) sentences, as well as to envelope-matched amplitude-modulated noise. We estimated coherence between the envelope of the acoustic input and MEG source time-series in two frequency bands corresponding to the mean syllable rates of the normal and fast speech stimuli. We found that listening to natural speech at normal and fast rates was associated with coupling between speech signal envelope and neural oscillations in right auditory and (pre)motor cortices. This oscillatory alignment occurred within [5.7-7.7 Hz] for normal rate sentences and shifted up to [8-10 Hz] for naturally-produced fast speech, mirroring the increase in syllable rate between the two conditions. Unexpectedly, despite being generated at the same rate as naturally-produced fast speech, the time-compressed sentences did not lead to significant cortico-acoustic coupling at [8-10 Hz]. In addition, neural activity in articulatory cortex exhibited stronger tuning to natural fast rather than to artificially accelerated speech, reflecting enhanced mapping to articulatory features of natural speech. Finally, we observed no coupling when participants listened to amplitude-modulated noise, which suggests that envelope tracking does not only reflect passive acoustic tracking but is sensitive to linguistic information. Altogether, our findings provide new insights into the oscillatory brain signature underlying the perception of natural speech at different rates and highlight the importance of using naturally-produced speech when probing the dynamics of brain-to-speech coupling