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Phase amplitude coupling

Bakul Gohel, Sanghyun Lim, Min-Young Kim, Kyung-Min An, Ji-Eun Kim, Hyukchan Kwon, Kiwoong Kim
Phase-amplitude coupling (PAC) plays an important role in neural communication and computation. Interestingly, recent studies have indicated the presence of ubiquitous PAC phenomenon even during the resting state. Despite the importance of PAC phenomenon, estimation of significant physiological PAC is challenging because of the lack of appropriate surrogate measures to control false positives caused by non-physiological PAC. Therefore, in the present study, we evaluated PAC phenomenon during resting-state magnetoencephalography (MEG) signal and considered various surrogate measures and computational approaches widely used in the literature in addition to proposing new ones...
2016: Frontiers in Computational Neuroscience
Robson Scheffer-Teixeira, Adriano Bl Tort
Phase-amplitude coupling between theta and multiple gamma sub-bands is a hallmark of hippocampal activity and believed to take part in information routing. More recently, theta and gamma oscillations were also reported to exhibit phase-phase coupling, or n:m phase-locking, suggesting an important mechanism of neuronal coding that has long received theoretical support. However, by analyzing simulated and actual LFPs, here we question the existence of theta-gamma phase-phase coupling in the rat hippocampus. We show that the quasi-linear phase shifts introduced by filtering lead to spurious coupling levels in both white noise and hippocampal LFPs, which highly depend on epoch length, and that significant coupling may be falsely detected when employing improper surrogate methods...
December 7, 2016: ELife
Etienne Combrisson, Marcela Perrone-Bertolotti, Juan Lp Soto, Golnoush Alamian, Philippe Kahane, Jean-Philippe Lachaux, Aymeric Guillot, Karim Jerbi
Goal-directed motor behavior is associated with changes in patterns of rhythmic neuronal activity across widely distributed brain areas. In particular, movement initiation and execution are mediated by patterns of synchronization and desynchronization that occur concurrently across distinct frequency bands and across multiple motor cortical areas. To date, motor-related local oscillatory modulations have been predominantly examined by quantifying increases or suppressions in spectral power. However, beyond signal power, spectral properties such as phase and phase-amplitude coupling (PAC) have also been shown to carry information with regards to the oscillatory dynamics underlying motor processes...
November 30, 2016: NeuroImage
R Ochoukov, V Bobkov, H Faugel, H Fünfgelder, J Jacquot, J-M Noterdaeme, G Suárez López
A new array of B-dot probes was installed on ASDEX Upgrade. The purpose of the new diagnostic is to study Ion Cyclotron Range-off Frequencies (ICRF) wave field distributions in the evanescent scrape-off layer (SOL) plasma region on the low field side of ASDEX Upgrade. The vacuum measurements (no gas, BT = 0 T) reveal ICRF wave field measurements consistent with the profiles expected from the newly installed 3-strap ICRF antennas outside the antenna box: the shape of the toroidal distribution of both the amplitude and the phase is the same for the case of only the central straps being active, as for the case of only the side straps being active...
November 2016: Review of Scientific Instruments
S Chakraborty, M Dandapathak, B C Sarkar
We explored analytically the oscillation quenching phenomena (amplitude death and parameter dependent inhomogeneous steady state) in a coupled third order phase locked loop (PLL) both in periodic and chaotic mode. The phase locked loops were coupled through mean field diffusive coupling. The lower and upper limits of the quenched state were identified in the parameter space of the coupled PLL using the Routh-Hurwitz technique. We further observed that the ability of convergence to the quenched state of coupled PLLs depends on the design parameters...
November 2016: Chaos
Jonathan Daume, Thomas Gruber, Andreas K Engel, Uwe Friese
: It has been suggested that cross-frequency phase-amplitude coupling (PAC) particularly in temporal brain structures serves as a neural mechanism for coordinated working memory storage. In this magnetoencephalography study, we show that during visual working memory maintenance, temporal cortex regions, which exhibit enhanced PAC, interact with prefrontal cortex via enhanced low-frequency phase synchronization. Healthy human participants were engaged in a visual delayed-matching-to-sample task with pictures of natural objects...
November 30, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Takefumi Ohki, Atsuko Gunji, Yuichi Takei, Hidetoshi Takahashi, Yuu Kaneko, Yosuke Kita, Naruhito Hironaga, Shozo Tobimatsu, Yoko Kamio, Takashi Hanakawa, Masumi Inagaki, Kazuo Hiraki
Though recent studies have elucidated the earliest mechanisms of processing in multisensory integration, our understanding of how multisensory integration of more sustained and complicated stimuli is implemented in higher-level association cortices is lacking. In this study, we used magnetoencephalography (MEG) to determine how neural oscillations alter local and global connectivity during multisensory integration processing. We acquired MEG data from 15 healthy volunteers performing an audio-visual speech matching task...
November 29, 2016: Scientific Reports
Roberto Fontana, Mario Agostini, Emanuele Murana, Mufti Mahmud, Elena Scremin, Maria Rubega, Giovanni Sparacino, Stefano Vassanelli, Cristina Fasolato
Alterations of brain network activity are observable in Alzheimer's disease (AD) together with the occurrence of mild cognitive impairment, before overt pathology. However, in humans as well in AD mouse models, identification of early biomarkers of network dysfunction is still at its beginning. We performed in vivo recordings of local field potential activity in the dentate gyrus of PS2APP mice expressing the human amyloid precursor protein (APP) Swedish mutation and the presenilin-2 (PS2) N141I. From a frequency-domain analysis, we uncovered network hyper-synchronicity as early as 3 months, when intracellular accumulation of amyloid beta was also observable...
November 5, 2016: Neurobiology of Aging
Lauren A Shreve, Anca Velisar, Mahsa Malekmohammadi, Mandy Miller Koop, Megan Trager, Emma J Quinn, Bruce C Hill, Zack Blumenfeld, Camilla Kilbane, Alessandra Mantovani, Jaimie M Henderson, Helen Brontë-Stewart
OBJECTIVE: Determine the incidence of resting state oscillations in alpha/beta, high frequency (HFO) bands, and their phase amplitude coupling (PAC) in a large cohort in Parkinson's disease (PD). METHODS: Intra-operative local field potentials (LFPs) from subthalamic nucleus (STN) were recorded from 100 PD subjects, data from 74 subjects were included in the analysis. RESULTS: Alpha/beta oscillations were evident in >99%, HFO in 87% and PAC in 98% of cases...
November 10, 2016: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
Chunsheng Li, Daniel Jacobs, Trevor Hilton, Martin Del Campo, Yotin Chinvarun, Peter L Carlen, Berj L Bardakjian
OBJECTIVE: The epileptogenic zone (EZ) is a brain region containing the sources of seizure genesis. Removal of the EZ is associated with cessation of seizures after resective surgical procedures, as measured by Engel Class I score. This study describes a novel EEG (electroencephalography) source imaging (ESI) method which uses cross-frequency coupled potential signals (SCFC) derived from scalp EEG. METHODS: Scalp EEG were recorded from ten patients (20 seizures) suffering from epilepsy...
December 2016: IEEE Transactions on Bio-medical Engineering
Chia-Yen Yang, Ching-Po Lin
Our previous study estimated the bias from the match attributes of the auditory and visual modalities related to a peaceful mood in the male brain. However, the interactions among the four main frequency bands of neural activity remain unknown. Therefore, this study uses magnetoencephalography to explore gender differences in the perceptions of auditory and visual modalities related to peaceful and fearful moods. Instead of analyzing single frequencies, this study analyzes interactions between low-frequency phase and high-frequency amplitude to reflect neural communication...
January 2, 2017: Journal of Neuroscience Research
Yves Bidaux, Alfredo Bismuto, Pietro Patimisco, Angelo Sampaolo, Tobias Gresch, Gregory Strubi, Stéphane Blaser, Frank K Tittel, Vincenzo Spagnolo, Antoine Muller, Jérôme Faist
We present a single mode multi-section quantum cascade laser source composed of three different sections: master oscillator, gain and phase section. Non-uniform pumping of the QCL's gain reveals that the various laser sections are strongly coupled. Simulations of the electronic and optical properties of the laser (based on the density matrix and scattering matrix formalisms, respectively) were performed and a good agreement with measurements is obtained. In particular, a pure modulation of the laser output power can be achieved...
November 14, 2016: Optics Express
Jing Wang, Jing Wang, Guo-Gang Xing, Xiaoli Li, You Wan
It has been reported that oscillatory gamma activity participates in brief acute pain and tonic ongoing pain. It is of great interest to determine whether the gamma activity is involved in chronic pain since chronic pain is a more severe pathological condition characterized by pain persistency. To investigate the oscillatory gamma activity in chronic pain, in the present study, we recorded spontaneous electrocorticogram (ECoG) signals during chronic pain development in rats with chronic inflammatory pain induced by monoarthritis...
2016: Frontiers in Neuroscience
Sophie N Koroloff, Alexander A Nevzorov
Spectroscopic assignment of NMR spectra for oriented uniformly labeled membrane proteins embedded in their native-like bilayer environment is essential for their structure determination. However, sequence-specific assignment in oriented-sample (OS) NMR is often complicated by insufficient resolution and spectral crowding. Therefore, the assignment process is usually done by a laborious and expensive "shotgun" method involving multiple selective labeling of amino acid residues. Presented here is a strategy to overcome poor spectral resolution in crowded regions of 2D spectra by selecting resolved "seed" residues via soft Gaussian pulses inserted into spin-exchange separated local-field experiments...
October 24, 2016: Journal of Magnetic Resonance
Ken-Ichi Inoue, Kazuya Watanabe, Toshiki Sugimoto, Yoshiyasu Matsumoto, Tomokazu Yasuike
Hot carriers at metal surfaces can drive nonthermal reactions of adsorbates. Characterizing nonequilibrium statistics among various degrees of freedom in an ultrafast time scale is crucial to understand and develop hot carrier-driven chemistry. Here we demonstrate multidimensional vibrational dynamics of carbon monoxide (CO) on Cu(100) along hot-carrier induced desorption studied by using time-resolved vibrational sum-frequency generation with phase-sensitive detection. Instantaneous frequency and amplitude of the CO internal stretching mode are tracked with a subpicosecond time resolution that is shorter than the vibrational dephasing time...
October 28, 2016: Physical Review Letters
Ross E F Harper, Peter Dayan, Joerg T Albert, Ralf Stanewsky
Periodic changes in light and temperature synchronize the Drosophila circadian clock, but the question of how the fly brain integrates these two input pathways to set circadian time remains unanswered. We explore multisensory cue combination by testing the resilience of the circadian network to conflicting environmental inputs. We show that misaligned light and temperature cycles can lead to dramatic changes in the daily locomotor activities of wild-type flies during and after exposure to sensory conflict...
November 8, 2016: Cell Reports
Naohiro Sugita, Toshihiko Sugiura
We investigated a bifurcation structure of coupled nonlinear oscillation of two spherical gas bubbles subject to a stationary sound field by means of nonlinear modal analysis. The goal of this paper is to describe an energy localization phenomenon of coupled two-bubble oscillators, resulting from symmetry-breaking bifurcation of the steady-state oscillation. Approximate asymptotic solutions of nonlinear normal modes (NNMs) and steady state oscillation are obtained based on the method of multiple scales. It is found that localized oscillation arises in a neighborhood of the localized normal modes...
February 2017: Ultrasonics
Yang Chen, Robert Halir, Íñigo Molina-Fernández, Pavel Cheben, Jian-Jun He
Chip-fiber grating couplers have been widely used in silicon-on-insulator platforms. In silicon nitride waveguides, the lower index contrast yields gratings with a weaker radiation strength and poor directionality, thereby limiting the coupling efficiency. Here we propose and design an apodized self-imaging grating coupler in silicon nitride that images an in-plane waveguide input to an output optical fiber placed at a specific distance above the chip. Both amplitude and phase apodizations are employed to engineer the transfer function of the self-imaging grating to produce an image field matching the fiber mode profile...
November 1, 2016: Optics Letters
Paolo Ranzi, Jan A Freund, Christiane M Thiel, Christoph S Herrmann
We present an encephalography (EEG) connectivity study where 30 healthy male nonsmokers were randomly allocated either to a nicotine group (14 subjects, 7 mg of transdermal nicotine) or to a placebo group. EEG activity was recorded in an eyes-open (EO) and eyes-closed (EC) condition before and after drug administration. This is a reanalysis of a previous dataset. Through a source reconstruction procedure, we extracted 13 time series representing 13 sources belonging to a resting-state network. Here, we conducted connectivity analysis (renormalized partial directed coherence; rPDC) on sources, focusing on the frequency range of 8...
November 2, 2016: Neuropsychobiology
Roberto C Sotero
Phase-amplitude coupling (PAC), a type of cross-frequency coupling (CFC) where the phase of a low-frequency rhythm modulates the amplitude of a higher frequency, is becoming an important indicator of information transmission in the brain. However, the neurobiological mechanisms underlying its generation remain undetermined. A realistic, yet tractable computational model of the phenomenon is thus needed. Here we analyze a neural mass model of a cortical column, comprising fourteen neuronal populations distributed across four layers (L2/3, L4, L5 and L6)...
November 2016: PLoS Computational Biology
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