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Phase amplitude coupling

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https://www.readbyqxmd.com/read/28343333/use-of-phase-locking-value-in-sensorimotor-rhythm-based-brain-computer-interface-zero-phase-coupling-and-effects-of-spatial-filters
#1
Wenjuan Jian, Minyou Chen, Dennis J McFarland
Phase-locking value (PLV) is a potentially useful feature in sensorimotor rhythm-based brain-computer interface (BCI). However, volume conduction may cause spurious zero-phase coupling between two EEG signals and it is not clear whether PLV effects are independent of spectral amplitude. Volume conduction might be reduced by spatial filtering, but it is uncertain what impact this might have on PLV. Therefore, the goal of this study was to explore whether zero-phase PLV is meaningful and how it is affected by spatial filtering...
March 25, 2017: Medical & Biological Engineering & Computing
https://www.readbyqxmd.com/read/28327465/anomalous-rashba-spin-orbit-interaction-in-electrically-controlled-topological-insulator-based-on-inn-gan-quantum-wells
#2
S P Lepkowski, Witold Bardyszewski
We study theoretically the topological phase transition and the Rashba spin-orbit interaction in electrically biased InN/GaN quantum wells. We show that that for properly chosen widths of quantum wells and barriers, one can effectively tune the system through the topological phase transition applying an external electric field perpendicular to the QW plane. We find that in InN/GaN quantum wells with the inverted band structure, when the conduction band s-type level is below the heavy hole and light hole p-type levels, the spin splitting of the subbands decreases with increasing the amplitude of the electric field in the quantum wells, which reveals the anomalous Rashba effect...
March 22, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28316753/a-resting-eeg-study-of-neocortical-hyperexcitability-and-altered-functional-connectivity-in-fragile-x-syndrome
#3
Jun Wang, Lauren E Ethridge, Matthew W Mosconi, Stormi P White, Devin K Binder, Ernest V Pedapati, Craig A Erickson, Matthew J Byerly, John A Sweeney
BACKGROUND: Cortical hyperexcitability due to abnormal fast-spiking inhibitory interneuron function has been documented in fmr1 KO mice, a mouse model of the fragile X syndrome which is the most common single gene cause of autism and intellectual disability. METHODS: We collected resting state dense-array electroencephalography data from 21 fragile X syndrome (FXS) patients and 21 age-matched healthy participants. RESULTS: FXS patients exhibited greater gamma frequency band power, which was correlated with social and sensory processing difficulties...
2017: Journal of Neurodevelopmental Disorders
https://www.readbyqxmd.com/read/28303088/commentary-phase-amplitude-coupling-at-the-organism-level-the-amplitude-of-spontaneous-alpha-rhythm-fluctuations-varies-with-the-phase-of-the-infra-slow-gastric-basal-rhythm
#4
COMMENT
https://www.readbyqxmd.com/read/28303035/a-compact-high-power-capable-and-tunable-high-directivity-microstrip-coupler
#5
Sung-Min Sohn, Anand Gopinath, John Thomas Vaughan
A coupler is an indispensable component to sample the forward and reflected power for the real-time radio frequency (RF) power monitoring system. The directivity of a coupler is a critical factor to achieve accurate RF power measurements. This paper proposes a microstrip coupler with a tunable high directivity circuit to accurately measure the reflected RF power. The directivity tuner composed of passive components adjusts phase and amplitude of the coupled RF signal, and cancel out the leakage signal from the RF input port at the coupled reflection port...
October 2016: IEEE Transactions on Microwave Theory and Techniques
https://www.readbyqxmd.com/read/28297967/all-phononic-amplification-in-coupled-cantilever-arrays-based-on-gap-soliton-dynamics
#6
Merab Malishava
We present a mechanism of amplification of phonons by phonons on the basis of nonlinear band-gap transmission phenomenon. As a concept the idea may be applied to the various number of systems; however we introduce the specific idea of creating an amplification scenario in the chain of coupled cantilever arrays. One chain is driven at the constant frequency located in the upper band of the ladder system, thus no wave enters the system. However the frequency is specifically chosen to be very close to the maximum value of the frequency corresponding to the dispersion relation of the system...
February 2017: Physical Review. E
https://www.readbyqxmd.com/read/28295094/excess-carrier-envelope-phase-noise-generation-in-saturable-absorbers
#7
Nils Raabe, Tianli Feng, Mark Mero, Haochen Tian, Youjian Song, Wolfgang Hänsel, Ronald Holzwarth, Alexander Sell, Armin Zach, Günter Steinmeyer
Attosecond spectroscopy and precision frequency metrology depend on the stabilization of the carrier-envelope phase (CEP) of mode-locked lasers. Unfortunately, the phase of only a few types of lasers can be stabilized to jitters in the few-hundred millirad range. In a comparative experimental study, we analyze a femtosecond Ti:sapphire laser and three mode-locked fiber lasers. We numerically demodulate recorded time series of the free-running carrier-envelope beat note. Our analysis indicates a correlation between amplitude and frequency fluctuations at low Fourier frequencies for essentially all lasers investigated...
March 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/28288120/0-%C3%AF-phase-controllable-thermal-josephson-junction
#8
Antonio Fornieri, Giuliano Timossi, Pauli Virtanen, Paolo Solinas, Francesco Giazotto
Two superconductors coupled by a weak link support an equilibrium Josephson electrical current that depends on the phase difference ϕ between the superconducting condensates. Yet, when a temperature gradient is imposed across the junction, the Josephson effect manifests itself through a coherent component of the heat current that flows opposite to the thermal gradient for |ϕ| < π/2 (refs 2-4). The direction of both the Josephson charge and heat currents can be inverted by adding a π shift to ϕ...
March 13, 2017: Nature Nanotechnology
https://www.readbyqxmd.com/read/28270595/differential-responses-of-rabbit-ventricular-and-atrial-transient-outward-current-ito-to-the-ito-modulator-ns5806
#9
Hongwei Cheng, Mark B Cannell, Jules C Hancox
Transient outward potassium current (Ito) in the heart underlies phase 1 repolarization of cardiac action potentials and thereby affects excitation-contraction coupling. Small molecule activators of Ito may therefore offer novel treatments for cardiac dysfunction, including heart failure and atrial fibrillation. NS5806 has been identified as a prototypic activator of canine Ito This study investigated, for the first time, actions of NS5806 on rabbit atrial and ventricular Ito Whole cell patch-clamp recordings of Ito and action potentials were made at physiological temperature from rabbit ventricular and atrial myocytes...
March 2017: Physiological Reports
https://www.readbyqxmd.com/read/28269508/cross-frequency-coupling-during-auditory-perception-in-human-cortex
#10
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
#11
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
#12
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/28268498/phase-amplitude-coupling-analysis-for-seizure-evolvement-using-hilbert-huang-transform
#13
Hanyue Zhou, Ying Li, Yue-Loong Hsin, Wentai Liu
Recent studies show that the phase-amplitude coupling (PAC) may play a functional role in information processing and cognition. The conventional method for PAC analysis is implemented by using Fourier-based filters, which assumes the signal is stationary and linear. However, as biological signals are nonstationary and nonlinear, this method introduces inaccuracy. To solve this problem, a new method based on Hilbert Huang Transform (HHT) is proposed in this paper, and is applied to analyze intracranial signals from two epilepsy patients...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28268354/phase-to-amplitude-coupling-as-a-potential-biomarker-for-creative-ideation-an-eeg-study
#14
Mina Marmpena, Stavros I Dimitriadis, Nitish Thakor, Anastasios Bezerianos
The most consistent finding of creative ideation in the neuroscientific study of creativity is the increment of EEG α power. However, the majority of existing studies focused only on ERP experimental paradigms while only a few analyzed time-related changes of EEG α power patterns during the time unlocked creation of ideas. Here, we designed an experimental paradigm where the participants were asked to generate alternative uses of everyday objects (AU task). For the control task, we adopted an Object Characteristics (OC) task, for which participants were asked to list typical characteristics or properties of an object...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28253082/multimodal-imaging-evidence-for-a-frontocortical-modulation-of-visual-cortex-during-the-selective-processing-of-conditioned-threat
#15
Nathan M Petro, L Forest Gruss, Siyang Yin, Haiqing Huang, Vladimir Miskovic, Mingzhou Ding, Andreas Keil
Emotionally salient cues are detected more readily, remembered better, and evoke greater visual cortical responses compared with neutral stimuli. The current study used concurrent EEG-fMRI recordings to identify large-scale network interactions involved in the amplification of visual cortical activity when viewing aversively conditioned cues. To generate a continuous neural signal from pericalcarine visual cortex, we presented rhythmic (10/sec) phase-reversing gratings, the orientation of which predicted the presence (CS+) or absence (CS-) of a cutaneous electric shock (i...
March 2, 2017: Journal of Cognitive Neuroscience
https://www.readbyqxmd.com/read/28253078/binding-by-random-bursts-a-computational-model-of-cognitive-control
#16
Tom Verguts
A neural synchrony model of cognitive control is proposed. It construes cognitive control as a higher-level action to synchronize lower-level brain areas. Here, a controller prefrontal area (medial frontal cortex) can synchronize two cortical processing areas. The synchrony is achieved by a random theta frequency-locked neural burst sent to both areas. The choice of areas that receive this burst is determined by lateral frontal cortex. As a result of this synchrony, communication between the two areas becomes more efficient...
March 2, 2017: Journal of Cognitive Neuroscience
https://www.readbyqxmd.com/read/28244747/rapid-iron-reduction-rates-are-stimulated-by-high-amplitude-redox-fluctuations-in-a-tropical-forest-soil
#17
Brian Ginn, Christof Meile, Jared Wilmoth, Yuanzhi Tang, Aaron Thompson
Iron oxides are important structural and biogeochemical components of soils that can be strongly altered by redox-driven processes. This study examined the influence of temporal oxygen variations on Fe speciation in soils from the Luquillo Critical Zone Observatory (Puerto Rico). We incubated soils under cycles of oxic-anoxic conditions (τoxic:τanoxic = 1:6) at three frequencies with and without phosphate addition. Fe(II) production, P availability, and Fe mineral composition were monitored using batch analytical and spectroscopic techniques...
February 28, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28241592/cavity-based-linear-to-circular-polarization-converter
#18
Jiang Wang, Wen Wu
This paper presents a polarization converter to convert a linearly polarized (LP) incident wave into an outgoing circularly polarized (CP) wave. It is constructed by a 2D array of thin cavities, with each cavity etched with three slots. The front slot is used to couple the LP wave into the cavity, while the backside orthogonal slots are utilized to couple the field out of the cavity with the same amplitude and 90° out-of-phase; subsequently, a CP wave is formed at the other side of the converter. As a proof-of-concept, a sample of the proposed converter is fabricated and measured in the microwave regime...
February 20, 2017: Optics Express
https://www.readbyqxmd.com/read/28227760/cross-frequency-coupling-during-auditory-perception-in-human-cortex
#19
Urszula Malinowska, Dana Boatman-Reich, Urszula Malinowska, Dana Boatman-Reich, 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/28227759/mining-cross-frequency-coupling-microstates-cfc%C3%AE-states-from-eeg-recordings-during-resting-state-and-mental-arithmetic-tasks
#20
Stavros I Dimitriadis, Yu Sun, Nitish Thakor, Anastasios Bezerianos, Stavros I Dimitriadis, Yu Sun, Nitish Thakor, Anastasios Bezerianos, 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
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