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Cross-frequency coupling

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https://www.readbyqxmd.com/read/28427024/knowledge-attitude-and-practice-about-epilepsy-among-teachers-at-ethio-national-school-addis-ababa-ethiopia
#1
Tesfaye Berhe, Bethlehem Yihun, Emebet Abebe, Hailu Abera
BACKGROUND: Epilepsy is one of the most common serious chronic brain disorders and is poorly understood by the public and has been associated with numerous misconceptions and beliefs. This, coupled with its dramatic clinical manifestations, has resulted in a strong social stigma. Since teachers have a key role in society as educators, the purpose of this study was to find out the knowledge, attitude, and practice towards epilepsy among school teachers. METHODS: A cross-sectional study design was used to assess the knowledge, attitude, and practice of 135 teachers about epilepsy using a semi-structured, self-administered questionnaire...
April 17, 2017: Epilepsy & Behavior: E&B
https://www.readbyqxmd.com/read/28424606/bifurcation-analysis-on-phase-amplitude-cross-frequency-coupling-in-neural-networks-with-dynamic-synapses
#2
Takumi Sase, Yuichi Katori, Motomasa Komuro, Kazuyuki Aihara
We investigate a discrete-time network model composed of excitatory and inhibitory neurons and dynamic synapses with the aim at revealing dynamical properties behind oscillatory phenomena possibly related to brain functions. We use a stochastic neural network model to derive the corresponding macroscopic mean field dynamics, and subsequently analyze the dynamical properties of the network. In addition to slow and fast oscillations arising from excitatory and inhibitory networks, respectively, we show that the interaction between these two networks generates phase-amplitude cross-frequency coupling (CFC), in which multiple different frequency components coexist and the amplitude of the fast oscillation is modulated by the phase of the slow oscillation...
2017: Frontiers in Computational Neuroscience
https://www.readbyqxmd.com/read/28424297/magnitude-and-behavior-of-cross-talk-effects-in-multi-channel-electrophysiology-experiments
#3
Matthew John Nelson, Silvana Valtcheva, Laurent Venance
Modern neurophysiological experiments frequently involve multiple channels separated by very small distances. A unique methodological concern for multiple electrode experiments is that of capacitive coupling (cross-talk) between channels. Yet the nature of the cross-talk recording circuit is not well known in the field and the extent to which it practically affects neurophysiology experiments has never been fully investigated. Here we describe a simple electrical circuit model of simultaneous recording and stimulation with two or more channels and experimentally verify the model using ex vivo brain slice and in vivo whole-brain preparations...
April 19, 2017: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28400257/phase-amplitude-coupled-persistent-theta-and-gamma-oscillations-in-rat-primary-motor-cortex-in%C3%A2-vitro
#4
Nicholas W Johnson, Mazhar Özkan, Adrian P Burgess, Emma J Prokic, Keith A Wafford, Michael J O'Neill, Stuart D Greenhill, Ian M Stanford, Gavin L Woodhall
In vivo, theta (4-7 Hz) and gamma (30-80 Hz) neuronal network oscillations are known to coexist and display phase-amplitude coupling (PAC). However, in vitro, these oscillations have for many years been studied in isolation. Using an improved brain slice preparation technique we have, using co-application of carbachol (10 μM) and kainic acid (150 nM), elicited simultaneous theta (6.6 ± 0.1 Hz) and gamma (36.6 ± 0.4 Hz) oscillations in rodent primary motor cortex (M1). Each oscillation showed greatest power in layer V...
April 8, 2017: Neuropharmacology
https://www.readbyqxmd.com/read/28396638/physiological-mechanisms-mediating-the-coupling-between-heart-period-and-arterial-pressure-in-response-to-postural-changes-in-humans
#5
Alessandro Silvani, Giovanna Calandra-Buonaura, Blair D Johnson, Noud van Helmond, Giorgio Barletta, Anna G Cecere, Michael J Joyner, Pietro Cortelli
The upright posture strengthens the coupling between heart period (HP) and systolic arterial pressure (SAP) consistently with a greater contribution of the arterial baroreflex to cardiac control, while paradoxically decreasing cardiac baroreflex sensitivity (cBRS). To investigate the physiological mechanisms that mediate the coupling between HP and SAP in response to different postures, we analyzed the cross-correlation functions between low-frequency HP and SAP fluctuations and estimated cBRS with the sequence technique in healthy male subjects during passive head-up tilt test (HUTT, n = 58), during supine wakefulness, supine slow-wave sleep (SWS), and in the seated and active standing positions (n = 8), and during progressive loss of 1 L blood (n = 8) to decrease central venous pressure in the supine position...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28380064/a-neural-mass-model-of-cross-frequency-coupling
#6
Mojtaba Chehelcheraghi, Cees van Leeuwen, Erik Steur, Chie Nakatani
Electrophysiological signals of cortical activity show a range of possible frequency and amplitude modulations, both within and across regions, collectively known as cross-frequency coupling. To investigate whether these modulations could be considered as manifestations of the same underlying mechanism, we developed a neural mass model. The model provides five out of the theoretically proposed six different coupling types. Within model components, slow and fast activity engage in phase-frequency coupling in conditions of low ambient noise level and with high noise level engage in phase-amplitude coupling...
2017: PloS One
https://www.readbyqxmd.com/read/28364980/sexual-quality-of-life-and-needs-for-sexology-care-of-cancer-patients-admitted-for-radiotherapy-a-3-month-cross-sectional-study-in-a-regional-comprehensive-reference-cancer-center
#7
Thierry Almont, Martine Delannes, Anne Ducassou, André Corman, Pierre Bondil, Elizabeth Moyal, Leslie Schover, Eric Huyghe
BACKGROUND: Providing early and better care in onco-sexuality and a better understanding of the sexual health care needs of patients before they start treatment is required. OBJECTIVE: To assess sexual quality of life and need for sexology care of patients when they are starting radiotherapy. DESIGN: We performed a cross-sectional study of adult patients with cancer admitted for radiotherapy treatment in a regional comprehensive cancer center...
April 2017: Journal of Sexual Medicine
https://www.readbyqxmd.com/read/28358482/surface-enhanced-infrared-spectroscopy-using-resonant-nanoantennas
#8
Frank Neubrech, Christian Huck, Ksenia Weber, Annemarie Pucci, Harald Giessen
Infrared spectroscopy is a powerful tool widely used in research and industry for a label-free and unambiguous identification of molecular species. Inconveniently, its application to spectroscopic analysis of minute amounts of materials, for example, in sensing applications, is hampered by the low infrared absorption cross-sections. Surface-enhanced infrared spectroscopy using resonant metal nanoantennas, or short "resonant SEIRA", overcomes this limitation. Resonantly excited, such metal nanostructures feature collective oscillations of electrons (plasmons), providing huge electromagnetic fields on the nanometer scale...
March 30, 2017: Chemical Reviews
https://www.readbyqxmd.com/read/28302093/determination-of-the-predictive-factors-of-long-lasting-insecticide-treated-net-ownership-and-utilisation-in-the-bamenda-health-district-of-cameroon
#9
Eric B Fokam, Germaine F Kindzeka, Leonard Ngimuh, Kevin T J Dzi, Samuel Wanji
BACKGROUND: Malaria is a serious health concern in Africa. In Cameroon, an endemic country where malaria remains a major public health problem, several control measures have been put in place among which the use of insecticide-treated bednets (LLINs/ITNs) is considered one of the core vector control strategies. However, the greatest challenges include ownership and utilisation by individuals and households. Factors such as age, marital status, gender, education and occupation of the household head, household size, knowledge of bednets, socioeconomic status, and environmental factors have been suggested to have an impact on bednet ownership and utilisation in different settings...
March 16, 2017: BMC Public Health
https://www.readbyqxmd.com/read/28298111/-1-h-2-h-cross-polarization-nmr-in-fast-spinning-solids-by-adiabatic-sweeps
#10
Sungsool Wi, Robert Schurko, Lucio Frydman
Cross-polarization (CP) experiments employing frequency-swept radiofrequency (rf) pulses have been successfully used in static spin systems for obtaining broadband signal enhancements. These experiments have been recently extended to heteronuclear I, S = spin-1/2 nuclides under magic-angle spinning (MAS), by applying adiabatic inversion pulses along the S (low-γ) channel while simultaneously applying a conventional spin-locking pulse on the I-channel ((1)H). This study explores an extension of this adiabatic frequency sweep concept to quadrupolar nuclei, focusing on CP from (1)H (I = 1/2) to (2)H spins (S = 1) undergoing fast MAS (νr = 60 kHz)...
March 14, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28297889/time-varying-coupling-functions-dynamical-inference-and-cause-of-synchronization-transitions
#11
Tomislav Stankovski
Interactions in nature can be described by their coupling strength, direction of coupling, and coupling function. The coupling strength and directionality are relatively well understood and studied, at least for two interacting systems; however, there can be a complexity in the interactions uniquely dependent on the coupling functions. Such a special case is studied here: synchronization transition occurs only due to the time variability of the coupling functions, while the net coupling strength is constant throughout the observation time...
February 2017: Physical Review. E
https://www.readbyqxmd.com/read/28291363/-13-c-decoupled-j-coupling-spectroscopy-using-two-dimensional-nuclear-magnetic-resonance-at-zero-field
#12
Tobias F Sjolander, Michael C D Tayler, Arne Kentner, Dmitry Budker, Alexander Pines
We present a two-dimensional method for obtaining (13)C-decoupled, (1)H-coupled nuclear magnetic resonance (NMR) spectra in zero magnetic field using coherent spin-decoupling. The result is a spectrum determined only by the proton-proton J-coupling network. Detection of NMR signals in zero magnetic field requires at least two different nuclear spin species, but the proton J-spectrum is independent of isotopomer, thus potentially simplifying spectra and thereby improving the analytical capabilities of zero-field NMR...
March 21, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/28288311/screening-of-biocides-metals-and-antibiotics-in-swedish-sewage-sludge-and-wastewater
#13
Marcus Östman, Richard H Lindberg, Jerker Fick, Erik Björn, Mats Tysklind
Incoming sewage water, treated effluent and digested sludge were collected from 11 Swedish sewage treatment plants (STPs) on 3 different days. Analytical protocols were established for a large number of compounds (47) with antimicrobial properties and the collected samples were then screened for the presence of these selected substances. Liquid chromatography tandem mass spectrometry (LC-MS/MS) and inductively coupled plasma mass spectrometry (ICP-MS) were used to analyse the samples. Thirty organic compounds and 10 metals were detected above their respective detection limit...
March 6, 2017: Water Research
https://www.readbyqxmd.com/read/28280880/differences-in-postural-tremor-dynamics-with-age-and-neurological-disease
#14
Steven Morrison, Karl M Newell, Justin J Kavanagh
The overlap of dominant tremor frequencies and similarly amplified tremor observed for Parkinson's disease (PD) and essential tremor (ET) means differentiating between these pathologies is often difficult. As tremor exhibits non-linear properties, employing both linear and non-linear analyses may help distinguish between the tremor dynamics of aging, PD and ET. This study was designed to examine postural tremor in healthy older adults, PD and ET using standard linear and non-linear metrics. Hand and finger postural tremor was recorded in 15 healthy older adults (64 ± 6 years), 15 older individuals with PD (63 ± 6 years), and 10 persons with ET (68 ± 7 years)...
March 9, 2017: Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale
https://www.readbyqxmd.com/read/28272522/frequency-phase-analysis-of-resting-state-functional-mri
#15
Gadi Goelman, Rotem Dan, Filip Růžička, Ondrej Bezdicek, Evžen Růžička, Jan Roth, Josef Vymazal, Robert Jech
We describe an analysis method that characterizes the correlation between coupled time-series functions by their frequencies and phases. It provides a unified framework for simultaneous assessment of frequency and latency of a coupled time-series. The analysis is demonstrated on resting-state functional MRI data of 34 healthy subjects. Interactions between fMRI time-series are represented by cross-correlation (with time-lag) functions. A general linear model is used on the cross-correlation functions to obtain the frequencies and phase-differences of the original time-series...
March 8, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28269508/cross-frequency-coupling-during-auditory-perception-in-human-cortex
#16
Urszula Malinowska, Dana Boatman-Reich
Cross-frequency coupling plays an important role in coordinating neuronal computations underlying human perception, learning and memory. Here we compared four methods for measuring phase/amplitude coupling (PAC) of theta (4-7 Hz) and high-gamma (70-150 Hz) in intracranial electrocorticographic (ECoG) recordings. Time-frequency spectral and time-domain evoked responses were derived for comparison. All four methods showed significant increases in theta/high-gamma PAC in auditory cortex at sites where significant event-related increases in high-gamma power were also observed...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28269507/mining-cross-frequency-coupling-microstates-cfc%C3%AE-states-from-eeg-recordings-during-resting-state-and-mental-arithmetic-tasks
#17
Stavros I Dimitriadis, Yu Sun, Nitish Thakor, Anastasios Bezerianos
The functional brain connectivity has been studied by analyzing synchronization between dynamic oscillations of identical frequency or between different frequencies of distinct brain areas. It has been hypothesized that cross-frequency coupling (CFC) between different frequency bands is the carrier mechanism for the coordination of global and local neural processes and hence supports the distributed information processing in the brain. In the present study, we attempt to study the dynamic evolution of CFC at resting-state and during a mental task...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28269506/mining-cross-frequency-coupling-microstates-from-resting-state-meg-an-application-to-mild-traumatic-brain-injury
#18
Marios Antonakakis, Stavros I Dimitriadis, Michalis Zervakis, Andrew C Papanicolaou, George Zouridakis
Recent studies have investigated the possible role of dynamic functional connectivity and the role of cross-frequency coupling (CFC) to provide the substrate for reliable biomarkers of brain disorders. In this study, we analyzed time-varying CFC profiles from resting state Magnetoencephal-ographic recordings of 30 mild Traumatic Brain Injury (mTBI) patients and 50 normal controls. Interactions among sensors at specific pairs of frequency bands were computed via estimation of phase-to-amplitude couplings. We then computed time-varying functional connectivity graphs that were described in terms of segregation (local efficiency, LE) and integration (global efficiency, GE) and mapped those graphs to time series of GE/LE estimates...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28269505/feasibility-study-for-the-assessment-of-cardio-respiratory-coupling-in-newborn-infants
#19
Maristella Lucchini, William P Fifer, Manuela Ferrario, Maria G Signorini
Cardio Respiratory Coupling (CRC) plays a key role during infant development. Nonetheless, mechanisms underlying it are still mostly unexplained and tools to assess it are often inadequate to understand its functioning. This study aims to evaluate the feasibility of CRC activity detection and quantification analyzing ECG and respiration of newborn healthy subjects. Cross-spectral analysis (coherence) and a novel application of a nonlinear method (Bivariate Phase Rectified Signal Averaging) were applied on 10 minutes recording from 4 subjects...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28268981/application-of-independent-component-analysis-to-remove-linear-dependencies-in-eeg-recorded-in-hippocampus
#20
J Harry Blaise, Taikang Ning
Linear cross-spectral and nonlinear cross-bispectral analysis techniques were applied to EEG data recorded simultaneously in two subfields (CA1 and dentate gyrus) of the hippocampus in freely behaving neonatal rats during REM sleep. Linear dependencies between the two sites were specifically removed using independent component analysis (ICA). The cross-spectrum and the cross-bispectrum computed prior to ICA processing were compared with those after ICA processing to determine its effects. Our results indicate that ICA almost completely extracts the linear relationship in the theta frequency band between CA1 and the dentate gyrus...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
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