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Phase amplitude coupling

Douglas McLelland, Rufin VanRullen
Several theories have been advanced to explain how cross-frequency coupling, the interaction of neuronal oscillations at different frequencies, could enable item multiplexing in neural systems. The communication-through-coherence theory proposes that phase-matching of gamma oscillations between areas enables selective processing of a single item at a time, and a later refinement of the theory includes a theta-frequency oscillation that provides a periodic reset of the system. Alternatively, the theta-gamma neural code theory proposes that a sequence of items is processed, one per gamma cycle, and that this sequence is repeated or updated across theta cycles...
October 2016: PLoS Computational Biology
Rong Yu, Andriy H Nevidomskyy
We study the symmetry and strength of the superconducting pairing in a two-orbital [Formula: see text] model for iron pnictides using the slave boson strong coupling approach. We show that the nearest-neighbor biquadratic interaction [Formula: see text] strongly affects the superconducting pairing phase diagram by promoting the [Formula: see text] B 1g and the [Formula: see text] A 1g channels. The resulting phase diagram consists of several competing pairing channels, including the isotropic [Formula: see text] A 1g channel, an anisotropic [Formula: see text] B 1g channel, and two [Formula: see text] pairing channels...
October 13, 2016: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Joohi Jimenez-Shahed, Ilknur Telkes, Ashwin Viswanathan, Nuri F Ince
Background: Deep brain stimulation (DBS) is an emerging treatment strategy for severe, medication-refractory Tourette syndrome (TS). Thalamic (Cm-Pf) and pallidal (including globus pallidus interna, GPi) targets have been the most investigated. While the neurophysiological correlates of Parkinson's disease (PD) in the GPi and subthalamic nucleus (STN) are increasingly recognized, these patterns are not well characterized in other disease states. Recent findings indicate that the cross-frequency coupling (CFC) between beta band and high frequency oscillations (HFOs) within the STN in PD patients is pathologic...
2016: Frontiers in Neuroscience
Shennan A Weiss, Iren Orosz, Noriko Salamon, Stephanie Moy, Linqing Wei, Maryse A Van't Klooster, Robert T Knight, Ronald M Harper, Anatol Bragin, Itzhak Fried, Jerome Engel, Richard J Staba
OBJECTIVE: Ripples (80-150 Hz) recorded from clinical macroelectrodes have been shown to be an accurate biomarker of epileptogenic brain tissue. We investigated coupling between epileptiform spike phase and ripple amplitude to better understand the mechanisms that generate this type of pathologic ripple (pRipple) event. METHODS: We quantified phase amplitude coupling (PAC) between epileptiform electroencephalography (EEG) spike phase and ripple amplitude recorded from intracranial depth macroelectrodes during episodes of sleep in 12 patients with mesial temporal lobe epilepsy...
October 10, 2016: Epilepsia
Maria Rubega, Roberto Fontana, Stefano Vassanelli, Giovanni Sparacino
The quantitative study of cross-frequency coupling (CFC) is a relevant issue in neuroscience. In local field potentials (LFPs), measured either in the cortex or in the hippocampus, how γ-oscillation amplitude is modulated by changes in θ-rhythms-phase is thought to be important in memory formation. Several methods were proposed to quantify CFC, but reported evidence suggests that experimental parameters affect the results. Therefore, a simulation tool to support the determination of minimal requirements for CFC estimation in order to obtain reliable results is particularly useful...
August 11, 2016: Network: Computation in Neural Systems
Ning Cheng, Qun Li, Xiaxia Xu, Tao Zhang
Neuronal information can be coded in different temporal and spatial scales. Cross-frequency coupling of neuronal oscillations, especially phase-amplitude coupling (PAC), plays a critical functional role in neuronal communication and large scale neuronal encoding. Several approaches have been developed to assess PAC intensity. It is generally agreed that the PAC intensity relates to the uneven distribution of the fast oscillation amplitude conditioned on the slow oscillation phase. However, it is still not clear what the PAC intensity exactly means...
2016: PloS One
Peter M Narins
Frogs and toads are capable of producing calls at potentially damaging levels that exceed 110 dB SPL at 50 cm. Most frog species have internally coupled ears (ICE) in which the tympanic membranes (TyMs) communicate directly via the large, permanently open Eustachian tubes, resulting in an inherently directional asymmetrical pressure-difference receiver. One active mechanism for auditory sensitivity reduction involves the pressure increase during vocalization that distends the TyM, reducing its low-frequency airborne sound sensitivity...
October 3, 2016: Biological Cybernetics
Weijia Lu, Bruno Haider
BACKGROUND AND PURPOSE: The twinkling sign in B-flow imaging (BFI-TS) has been reported in the literature to increase both specificity and sensitivity compared to the traditional gray-scale imaging. Unfortunately, there has been no conclusive study on the mechanism of this effect. METHODS: In the study presented here, a comparative test on phantoms is introduced, where the variance of a phase estimator is used to quantify the motion amplitude. The statistical inference is employed later to find the dominate factor for the twinkling sign, which is proven by computer simulation...
September 29, 2016: Journal of Medical Ultrasonics
Stavros I Dimitriadis, Yu Sun, Nitish V Thakor, Anastasios Bezerianos
Many neuroimaging studies have demonstrated the different functional contributions of spatially distinct brain areas to working memory (WM) subsystems in cognitive tasks that demand both local information processing and interregional coordination. In WM cognitive task paradigms employing electroencephalography (EEG), brain rhythms such as θ and α have been linked to specific functional roles over given brain areas, but their functional coupling has not been extensively studied. Here we analyzed an arithmetic task with five cognitive workload levels (CWLs) and demonstrated functional/effective coupling between the two WM subsystems: the central executive located over frontal (F) brain areas that oscillates on the dominant θ rhythm (Frontal(θ)/F(θ)) and the storage buffer located over parieto-occipital (PO) brain areas that operates on the α2 dominant brain rhythm (Parieto-Occipital(α2)/PO(α2))...
2016: Frontiers in Human Neuroscience
Soo-Jin Sohn, Chi-Yung Tam, Hye-In Jeong
The effects of amplitude and type of the El Niño-Southern Oscillation (ENSO) on sea surface temperature (SST) predictability on a global scale were investigated, by examining historical climate forecasts for the period 1982-2006 from air-sea coupled seasonal prediction systems. Unlike in previous studies, SST predictability was evaluated in different phases of ENSO and for episodes with various strengths. Our results reveal that the seasonal mean Niño 3.4 index is well predicted in a multi-model ensemble (MME), even for four-month lead predictions...
2016: Scientific Reports
Charmaine Demanuele, Ullrich Bartsch, Bengi Baran, Sheraz Khan, Mark G Vangel, Roy Cox, Matti Hämäläinen, Matthew W Jones, Robert Stickgold, Dara S Manoach
STUDY OBJECTIVES: Schizophrenia patients have correlated deficits in sleep spindle density and sleep-dependent memory consolidation. In addition to spindle density, memory consolidation is thought to rely on the precise temporal coordination of spindles with slow waves (SWs). We investigated whether this coordination is intact in schizophrenia and its relation to motor procedural memory consolidation. METHODS: Twenty-one chronic medicated schizophrenia patients and 17 demographically-matched healthy controls underwent two nights of polysomnography with training on the finger tapping motor sequence task (MST) on the second night and testing the following morning...
September 9, 2016: Sleep
Daniel Thengone, Khatuna Gagnidze, Donald Pfaff, Alex Proekt
The level of activity of many animals including humans rises and falls with a period of ~ 24 hours. The intrinsic biological oscillator that gives rise to this circadian oscillation is driven by a molecular feedback loop with an approximately 24 hour cycle period and is influenced by the environment, most notably the light:dark cycle. In addition to the circadian oscillations, behavior of many animals is influenced by multiple oscillations occurring at faster-ultradian-time scales. These ultradian oscillations are also thought to be driven by feedback loops...
2016: PloS One
Stanislav V Rozov, Janneke C Zant, Kestutis Gurevicius, Tarja Porkka-Heiskanen, Pertti Panula
AIM: Under natural conditions diurnal rhythms of biological processes of the organism are synchronized with each other and to the environmental changes by means of the circadian system. Disturbances of the latter affect hormonal levels, sleep-wakefulness cycle and cognitive performance. To study mechanisms of such perturbations animal models subjected to artificial photoperiods are often used. The goal of current study was to understand the effects of circadian rhythm disruption, caused by a short light-dark cycle regime, on activity of the cerebral cortex in rodents...
2016: Frontiers in Behavioral Neuroscience
K Ashoke Raman, Rajeev K Jaiman, Yi Sui, Thong-See Lee, Hong-Tong Low
The behavior of a droplet impinging onto a solid substrate can be influenced significantly by the horizontal motion of the substrate. The coupled interactions between the moving wall and the impacting droplet may result in various outcomes, which may be different from the usual normal droplet impact on a stationary wall. In this paper, we present a method to suppress drop rebound on hydrophobic surfaces via transverse wall oscillations, normal to the impact direction. The numerical investigation shows that the suppression of droplet rebound has a direct relationship with the oscillation phase, amplitude, and frequency...
August 2016: Physical Review. E
Ramesh Arumugam, Partha Sharathi Dutta, Tanmoy Banerjee
How landscape fragmentation affects ecosystems diversity and stability is an important and complex question in ecology with no simple answer, as spatially separated habitats where species live are highly dynamic rather than just static. Taking into account the species dispersal among nearby connected habitats (or patches) through a common dynamic environment, we model the consumer-resource interactions with a ring type coupled network. By characterizing the dynamics of consumer-resource interactions in a coupled ecological system with three fundamental mechanisms such as the interaction within the patch, the interaction between the patches, and the interaction through a common dynamic environment, we report the occurrence of various collective behaviors...
August 2016: Physical Review. E
Ruwani P Hewawasam, Dan Liu, Marco G Casarotto, Philip G Board, Angela F Dulhunty
The cardiac ryanodine receptor (RyR2) is an intracellular ion channel that regulates Ca2+ release from the sarcoplasmic reticulum (SR) during excitation-contraction coupling in the heart. The glutathione transferases (GSTs) are a family of phase II detoxification enzymes with additional functions including the selective inhibition of RyR2, with therapeutic implications. The C-terminal half of GSTM2 (GSTM2C) is essential for RyR2 inhibition, and mutations F157A and Y160A within GSTM2C prevent the inhibitory action...
2016: PloS One
Jiaxin Yu, Feng Liao, Fuxing Gu, Heping Zeng
The use of ultrashort pulses for fundamental studies and applications has been increasing rapidly in the past decades. Along with the development of ultrashort lasers, exploring new pulse diagnositic approaches with higher signal-to-noise ratio have attracted great scientific and technological interests. In this work, we demonstrate a simple technique of ultrashort pulses characterization with a single semiconductor nanowire. By performing a frequency-resolved optical gating method with a ZnO nanowire coupled to tapered optical microfibers, the phase and amplitude of a pulse series are extracted...
2016: Scientific Reports
Diego Lozano-Soldevilla, Niels Ter Huurne, Robert Oostenveld
Neuronal oscillations support cognitive processing. Modern views suggest that neuronal oscillations do not only reflect coordinated activity in spatially distributed networks, but also that there is interaction between the oscillations at different frequencies. For example, invasive recordings in animals and humans have found that the amplitude of fast oscillations (>40 Hz) occur non-uniformly within the phase of slower oscillations, forming the so-called cross-frequency coupling (CFC). However, the CFC patterns might be influenced by features in the signal that do not relate to underlying physiological interactions...
2016: Frontiers in Computational Neuroscience
Leonardo Rodríguez-Sosa, Gabina Calderón-Rosete, Aída Ortega-Cambranis, Francisco F De-Miguel
The biogenic amine octopamine (OA) modulates invertebrate behavior by changing neuronal responses from sensory inputs to motor outputs. However, the OA modulation of visual sensitivity and its possible coupling to diurnal cycles remains unexplored. Here we studied the diurnal variations in the OA levels in the hemolymph of the crayfish Procambarus clarkii, its release from the structures in the eyestalk and its modulation of the retinal light sensitivity. The hemolymph concentration of OA and its amino acid precursor tyrosine was measured by high-resolution liquid chromatography; OA varied along the 24-hcycle...
September 1, 2016: Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology
K Ramesh
BACKGROUND: Assessment of the fluid flow pattern in a non-pregnant uterus is important for understanding embryo transport in the uterus. Fertilization occurs in the fallopian tube and the embryo enters the uterine cavity within three days of ovulation. In the uterus, the embryo is conveyed by the uterine fluid for another three to four days to a successful implantation site at the upper part of the uterus. The movements of fluid within the uterus may be induced by several mechanisms, but they seem to be dominated by myometrial contractions...
October 2016: Computer Methods and Programs in Biomedicine
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