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HIgh Frequency Oscillation

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https://www.readbyqxmd.com/read/28239337/local-and-distant-dysregulation-of-synchronization-around-interictal-spikes-in-bects
#1
Emilie Bourel-Ponchel, Mahdi Mahmoudzadeh, Patrick Berquin, Fabrice Wallois
Objective: High Density electroencephalography (HD EEG) is the reference non-invasive technique to investigate the dynamics of neuronal networks in Benign Epilepsy with Centro-Temporal Spikes (BECTS). Analysis of local dynamic changes surrounding Interictal Epileptic Spikes (IES) might improve our knowledge of the mechanisms that propel neurons to the hypersynchronization of IES in BECTS. Transient distant changes in the dynamics of neurons populations may also interact with neuronal networks involved in various functions that are impaired in BECTS patients...
2017: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/28235667/automated-detection-of-high-frequency-oscillations-in-electrophysiological-signals-methodological-advances
#2
Miguel Navarrete, Jan Pyrzowski, Juliana Corlier, Mario Valderrama, Michel Le Van Quyen
In recent years, new recording technologies have advanced such that oscillations of neuronal networks can be identified from simultaneous, multisite recordings at high temporal and spatial resolutions. However, because of the deluge of multichannel data generated by these experiments, achieving the full potential of parallel neuronal recordings also depends on the development of new mathematical methods capable of extracting meaningful information related to time, frequency and space. In this review, we aim to bridge this gap by focusing on the new analysis tools developed for the automated detection of high-frequency oscillations (HFOs, > 40 Hz) in local field potentials...
February 21, 2017: Journal of Physiology, Paris
https://www.readbyqxmd.com/read/28227755/differentiation-of-spindle-associated-hippocampal-hfos-based-on-a-correlation-analysis
#3
Daniel Lachner Piza, Jonas C Bruder, Julia Jacobs, Andreas Schulze-Bonhage, Thomas Stieglitz, Matthias Dumpelmann, Daniel Lachner Piza, Jonas C Bruder, Julia Jacobs, Andreas Schulze-Bonhage, Thomas Stieglitz, Matthias Dumpelmann, Thomas Stieglitz, Matthias Dumpelmann, Jonas C Bruder, Andreas Schulze-Bonhage, Daniel Lachner Piza, Julia Jacobs
High Frequency Oscillations (HFOs) have been described as biomarkers of epileptogenic tissue; however their pathological/physiological classification poses a challenge to their predictive power. For the population of ripples co-occurring with sleep spindles, those ripples improving the antiparallel correlation of ripple-peaks and sleep spindle-troughs were classified as coupled-ripples and the rest as uncoupled-ripples. For the same population of ripples two reference groups called in-SOZ and non-SOZ were formed according to the ripples' location inside or outside the seizure onset zone (SOZ)...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227592/saw-lc-coupled-resonator-wideband-vco-for-medical-telemetry
#4
Madhav Venkateswaran, Mark Hillig, James E Brown, Paul J Stadnik, Jeffrey A Von Arx, Brian Sutton, Larry J Stotts, Madhav Venkateswaran, Mark Hillig, James E Brown, Paul J Stadnik, Jeffrey A Von Arx, Brian Sutton, Larry J Stotts, Mark Hillig, Jeffrey A Von Arx, Madhav Venkateswaran, Brian Sutton, James E Brown, Paul J Stadnik, Larry J Stotts
Wireless links with implantable devices can help in real-time monitoring of symptoms, irregularities, implanted device efficacy and their reconfiguration. We present the design of a low-power wideband voltage controlled oscillator (VCO) to facilitate implantable wireless telemetry. A coupled SAW-LC resonator design combines high Q and spectral purity of a SAW element and tunability of an LC-tank. The designed 2.7 MHz bandwidth VCO is suitable for full duplex communication protocols in the MedRadio band with frequency agility and higher duty cycles, in conformance with FCC regulations...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227337/prediction-of-the-outcome-in-cardiac-arrest-patients-undergoing-hypothermia-using-eeg-wavelet-entropy
#5
Hana Moshirvaziri, Nima Ramezan-Arab, Shadnaz Asgari, Hana Moshirvaziri, Nima Ramezan-Arab, Shadnaz Asgari, Hana Moshirvaziri, Nima Ramezan-Arab, Shadnaz Asgari
Cardiac arrest (CA) is the leading cause of death in the United States. Induction of hypothermia has been found to improve the functional recovery of CA patients after resuscitation. However, there is no clear guideline for the clinicians yet to determine the prognosis of the CA when patients are treated with hypothermia. The present work aimed at the development of a prognostic marker for the CA patients undergoing hypothermia. A quantitative measure of the complexity of Electroencephalogram (EEG) signals, called wavelet sub-band entropy, was employed to predict the patients' outcomes...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28226975/portable-forced-oscillation-device-for-point-of-care-pulmonary-function-testing
#6
Jian Cao, Ashutosh Sabharwal, Jian Cao, Ashutosh Sabharwal, Jian Cao, Ashutosh Sabharwal
The forced oscillation technique (FOT) provides a simple and accurate approach for pulmonary function testing. However, most current devices are large and high cost, hence the test remains sparingly used. To address this problem, we verified the feasibility of a smart and portable forced oscillation device based on a small subwoofer and ultrasonic sensor that is targeted at point-of-care pulmonary function testing. In this paper, we first develop and optimize the signal processing algorithm for impedance estimation...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28226670/computational-modeling-of-high-frequency-oscillations-recorded-with-clinical-intracranial-macroelectrodes
#7
M Shamas, P Benquet, I Merlet, W El Falou, M Khalil, F Wendling, M Shamas, P Benquet, I Merlet, W El Falou, M Khalil, F Wendling, M Khalil, P Benquet, I Merlet, W El Falou, M Shamas, F Wendling
High Frequency Oscillations (HFOs) are a potential biomarker of epileptogenic regions. They have been extensively investigated in terms of automatic detection, classification and feature extraction. However, the mechanisms governing the generation of HFOs as well as the observability conditions on clinical intracranial macroelectrodes remain elusive. In this paper, we propose a novel physiologically-relevant macroscopic model for accurate simulation of HFOs as invasively recorded in epileptic patients. This model accounts for both the temporal and spatial properties of the cortical patch at the origin of epileptiform activity...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28226654/multi-channel-algorithms-for-epileptic-high-frequency-oscillation-detection
#8
Chen-Wei Chou, Chien Chen, Shang-Yeong Kwan, Shun-Chi Wu, Chen-Wei Chou, Chien Chen, Shang-Yeong Kwan, Shun-Chi Wu, Chien Chen, Chen-Wei Chou, Shun-Chi Wu, Shang-Yeong Kwan
Short-lasting rhythmic activity in intracranial electroencephalogram (iEEG) in the frequency range of 80 to 500 Hz is regarded to be a promising biomarker of epileptogenicity. This activity is referred to as high-frequency oscillation (HFO), and its detection from iEEG is considered the first step to several applications. In this study, several multi-channel algorithms for HFO detection are proposed. With the proposed multi-channel statistics and threshold determination scheme, the algorithms allow HFO detection to be performed without breaking the iEEG channel structure and the detection threshold to be determined automatically...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28225007/full-3d-modelling-of-pulse-propagation-enables-efficient-nonlinear-frequency-conversion-with-low-energy-laser-pulses-in-a-single-element-tripler
#9
Tomasz M Kardaś, Michał Nejbauer, Paweł Wnuk, Bojan Resan, Czesław Radzewicz, Piotr Wasylczyk
Although new optical materials continue to open up access to more and more wavelength bands where femtosecond laser pulses can be generated, light frequency conversion techniques are still indispensable in filling the gaps on the ultrafast spectral scale. With high repetition rate, low pulse energy laser sources (oscillators) tight focusing is necessary for a robust wave mixing and the efficiency of broadband nonlinear conversion is limited by diffraction as well as spatial and temporal walk-off. Here we demonstrate a miniature third harmonic generator (tripler) with conversion efficiency exceeding 30%, producing 246 fs UV pulses via cascaded second order processes within a single laser beam focus...
February 22, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28224158/chaotic-variations-of-electrical-conductance-in-powdered-pd-correlating-with-oscillatory-sorption-of-d2
#10
E Lalik, G Mordarski, R P Socha, A Drelinkiewicz
A microcalorimetric method has been combined with a potentiostatic method to measure simultaneously the rate of heat evolution and the electrical current in a powdered sample of palladium during thermokinetic oscillations accompanying the sorption of deuterium in the metal. Deterministic chaos has been confirmed in the temporal variations in current (of ca. 1-4 mA) on the onset of both the sorption and the desorption of deuterium from Pd. It has been found that the first derivative of the current in time, dI/dt, turns out to be correlated precisely with the periodicity of thermokinetic oscillations...
February 22, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28223240/carbachol-induced-network-oscillations-in-an-in-vitro-limbic-system-brain-slice
#11
Maxime Lévesque, Mauro Cataldi, Li-Yuan Chen, Shabnam Hamidi, Massimo Avoli
We employed simultaneous field potential recordings from CA3, subiculum and entorhinal cortex in an in vitro brain slice preparation to understand the involvement of these limbic areas in the generation of the field potential oscillations that are induced by bath application of the muscarinic receptor agonist carbachol. Regularly spaced oscillations that mainly presented at theta frequency range (5-12 Hz) occurred synchronously in all three structures in the presence of carbachol. These oscillations, which disappeared when slices were perfused with pirenzepine or with glutamatergic receptor antagonists, were categorized as short (< 4 s) and long (> 4s) with short events oscillating at higher frequencies than long events...
February 18, 2017: Neuroscience
https://www.readbyqxmd.com/read/28220079/muro-neuro-urodynamics-a-review-of-the-functional-assessment-of-mouse-lower-urinary-tract-function
#12
REVIEW
Hiroki Ito, Anthony E Pickering, Yasuhiko Igawa, Anthony J Kanai, Christopher H Fry, Marcus J Drake
Background: Mouse urodynamic tests are fundamental to understanding normal lower urinary tract (LUT) function. These experiments also contribute to our understanding of neurological dysfunction, pathophysiological processes, and potential mechanisms of therapy. Objectives: Systematic assessment of published evidence on urodynamics, advantages and limitations of different urodynamic measurements in mice, and consideration of potential implications for the clinical field. Methods: A search using specific search-terms for urodynamic studies and mice was conducted on PubMed (from inception to 1 July 2016)...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28218853/new-information-on-the-hydrophobic-interaction-revealed-by-frequency-modulation-afm
#13
Itai Schlesinger, Uri Sivan
Using an ultra-high resolution AFM operated in frequency modulation mode we extend existing measurements of the force acting between hydrophobic surfaces immersed in water in three essential ways. (1) The measurement range, which was previously limited to distances longer than 2-3 nanometers, is extended to cover all distances, down to contact. The measurements disclose that the long-range attraction observed also by conventional techniques, turns at distances shorter than 1-2 nanometers into pronounced repulsion...
February 20, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28216627/layer-specific-optogenetic-activation-of-pyramidal-neurons-causes-beta-gamma-entrainment-of-neonatal-networks
#14
Sebastian H Bitzenhofer, Joachim Ahlbeck, Amy Wolff, J Simon Wiegert, Christine E Gee, Thomas G Oertner, Ileana L Hanganu-Opatz
Coordinated activity patterns in the developing brain may contribute to the wiring of neuronal circuits underlying future behavioural requirements. However, causal evidence for this hypothesis has been difficult to obtain owing to the absence of tools for selective manipulation of oscillations during early development. We established a protocol that combines optogenetics with electrophysiological recordings from neonatal mice in vivo to elucidate the substrate of early network oscillations in the prefrontal cortex...
February 20, 2017: Nature Communications
https://www.readbyqxmd.com/read/28213446/acetylcholine-release-in-prefrontal-cortex-promotes-gamma-oscillations-and-theta-gamma-coupling-during-cue-detection
#15
W M Howe, H J Gritton, N Lusk, Erik A Roberts, Vaughn L Hetrick, Joshua D Berke, Martin Sarter
The capacity for using external cues to guide behavior ("cue detection") constitutes an essential aspect of attention and goal-directed behavior. The cortical cholinergic input system, via phasic increases in prefrontal acetylcholine release, plays an essential role in attention by mediating such cue detection. However, the relationship between cholinergic signaling during cue detection and neural activity dynamics in prefrontal networks remains unclear. Here we combined sub-second measures of cholinergic signaling, neurophysiological recordings, and cholinergic receptor blockade to delineate the cholinergic contributions to prefrontal oscillations during cue detection in rats...
February 17, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28211999/platform-to-enable-combined-measurement-of-dopamine-and-neural-activity
#16
Kate L Parent, Daniel F Hill, Lindsey M Crown, Jean-Paul Wiegand, Kathleen F Gies, Michael A Miller, Christopher W Atcherley, Michael L Heien, Stephen L Cowen
Complex behaviors depend on the coordination of the activities of ensembles of neurons and the release of neuromodulators such as dopamine. The mechanisms underlying such coordination are not well-understood due to a lack of instrumentation for combined and real-time monitoring of neuromodulator release and the activities of large ensembles of neurons. Here we describe a measurement platform that allows for the combined monitoring of electrophysiology from a high-density electrode array and dopamine dynamics from a carbon-fiber microelectrode...
February 17, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28208443/density-of-states-and-dynamical-crossover-in-a-dense-fluid-revealed-by-exponential-mode-analysis-of-the-velocity-autocorrelation-function
#17
S Bellissima, M Neumann, E Guarini, U Bafile, F Barocchi
Extending a preceding study of the velocity autocorrelation function (VAF) in a simulated Lennard-Jones fluid [Phys. Rev. E 92, 042166 (2015)PLEEE81539-375510.1103/PhysRevE.92.042166] to cover higher-density and lower-temperature states, we show that the recently demonstrated multiexponential expansion method allows for a full account and understanding of the basic dynamical processes encompassed by a fundamental quantity as the VAF. In particular, besides obtaining evidence of a persisting long-time tail, we assign specific and unambiguous physical meanings to groups of exponential modes related to the longitudinal and transverse collective dynamics, respectively...
January 2017: Physical Review. E
https://www.readbyqxmd.com/read/28208395/collective-dynamics-of-time-delay-coupled-phase-oscillators-in-a-frustrated-geometry
#18
Bhumika Thakur, Devendra Sharma, Abhijit Sen, George L Johnston
We study the effect of time delay on the dynamics of a system of repulsively coupled nonlinear oscillators that are configured as a geometrically frustrated network. In the absence of time delay, frustrated systems are known to possess a high degree of multistability among a large number of coexisting collective states except for the fully synchronized state that is normally obtained for attractively coupled systems. Time delay in the coupling is found to remove this constraint and to lead to such a synchronized ground state over a range of parameter values...
January 2017: Physical Review. E
https://www.readbyqxmd.com/read/28208317/quantum-kramers-model-corrections-to-the-linear-response-theory-for-continuous-bath-spectrum
#19
Ilya Rips
Decay of the metastable state is analyzed within the quantum Kramers model in the weak-to-intermediate dissipation regime. The decay kinetics in this regime is determined by energy exchange between the unstable mode and the stable modes of thermal bath. In our previous paper [Phys. Rev. A 42, 4427 (1990)PLRAAN1050-294710.1103/PhysRevA.42.4427], Grabert's perturbative approach to well dynamics in the case of the discrete bath [Phys. Rev. Lett. 61, 1683 (1988)PRLTAO0031-900710.1103/PhysRevLett.61.1683] has been extended to account for the second order terms in the classical equations of motion (EOM) for the stable modes...
January 2017: Physical Review. E
https://www.readbyqxmd.com/read/28207393/optimization-of-the-close-to-carrier-phase-noise-in-a-cmos-mems-oscillator-using-a-phase-tunable-sustaining-amplifier
#20
Guillermo Sobreviela, Martin Riverola, Francesc Canals, Arantxa Del Monte, Nuria Beumala
In this paper, the phase noise of a 24-MHz CMOSMEMS oscillator with zero-level vacuum package is studied. We characterize and analyze the nonlinear regime of each one of the modules that compose the oscillator (CMOS sustaining-amplifier and MEMS resonator). As we show, the presented resonator exhibits a high nonlinear behavior. Such fact is exploited as a mechanism to stabilize the oscillation amplitude, allowing to maintain the sustaining-amplifier working in the linear regime. Consequently, the nonlinear resonator becomes the main closeto- carrier phase noise source...
February 13, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
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