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High frequency oscillations

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https://www.readbyqxmd.com/read/28213446/acetylcholine-release-in-prefrontal-cortex-promotes-gamma-oscillations-and-theta-gamma-coupling-during-cue-detection
#1
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
#2
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
#3
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
#4
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
#5
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
#6
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
https://www.readbyqxmd.com/read/28194984/signal-enhancement-with-stacked-magnets-for-high-resolution-radio-frequency-glow-discharge-mass-spectrometry
#7
Juan Wei, Jiangli Dong, Shangjun Zhuo, Rong Qian, Yuanxing Fang, Qiao Chen, Ekbal Patel
A method for signal enhancement utilizing stacked magnets was introduced into high-resolution radio frequency glow discharge-mass spectrometry (rf-GD-MS) for significantly improved analysis of inorganic materials. Compared to the block magnet, the stacked magnets method was able to achieve 50-59% signal enhancement for typical elements in Y2O3, BSO, and BTN samples. The results indicated that signal was enhanced as the increase of discharge pressure from 1.3 to 8.0 mPa, the increase of rf-power from 10 to 50 W with a frequency of 13...
January 17, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28194485/detection-of-hydrodynamic-stimuli-by-the-postcranial-body-of-florida-manatees-trichechus-manatus-latirostris
#8
Joseph C Gaspard, Gordon B Bauer, David A Mann, Katharine Boerner, Laura Denum, Candice Frances, Roger L Reep
Manatees live in shallow, frequently turbid waters. The sensory means by which they navigate in these conditions are unknown. Poor visual acuity, lack of echolocation, and modest chemosensation suggest that other modalities play an important role. Rich innervation of sensory hairs that cover the entire body and enlarged somatosensory areas of the brain suggest that tactile senses are good candidates. Previous tests of detection of underwater vibratory stimuli indicated that they use passive movement of the hairs to detect particle displacements in the vicinity of a micron or less for frequencies from 10 to 150 Hz...
February 13, 2017: Journal of Comparative Physiology. A, Neuroethology, Sensory, Neural, and Behavioral Physiology
https://www.readbyqxmd.com/read/28194133/current-and-emerging-potential-of-magnetoencephalography-in-the-detection-and-localization-of-high-frequency-oscillations-in-epilepsy
#9
REVIEW
Eleonora Tamilia, Joseph R Madsen, Patricia Ellen Grant, Phillip L Pearl, Christos Papadelis
Up to one-third of patients with epilepsy are medically intractable and need resective surgery. To be successful, epilepsy surgery requires a comprehensive preoperative evaluation to define the epileptogenic zone (EZ), the brain area that should be resected to achieve seizure freedom. Due to lack of tools and methods that measure the EZ directly, this area is defined indirectly based on concordant data from a multitude of presurgical non-invasive tests and intracranial recordings. However, the results of these tests are often insufficiently concordant or inconclusive...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28193862/differential-modulation-of-global-and-local-neural-oscillations-in-rem-sleep-by-homeostatic-sleep-regulation
#10
Bowon Kim, Bernat Kocsis, Eunjin Hwang, Youngsoo Kim, Robert E Strecker, Robert W McCarley, Jee Hyun Choi
Homeostatic rebound in rapid eye movement (REM) sleep normally occurs after acute sleep deprivation, but REM sleep rebound settles on a persistently elevated level despite continued accumulation of REM sleep debt during chronic sleep restriction (CSR). Using high-density EEG in mice, we studied how this pattern of global regulation is implemented in cortical regions with different functions and network architectures. We found that across all areas, slow oscillations repeated the behavioral pattern of persistent enhancement during CSR, whereas high-frequency oscillations showed progressive increases...
February 13, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28192762/neural-mass-models-describing-possible-origin-of-the-excessive-beta-oscillations-correlated-with-parkinsonian-state
#11
Chen Liu, Yulin Zhu, Fei Liu, Jiang Wang, Huiyan Li, Bin Deng, Chris Fietkiewicz, Kenneth A Loparo
In Parkinson's disease, the enhanced beta rhythm is closely associated with akinesia/bradykinesia and rigidity. An increase in beta oscillations (12-35 Hz) within the basal ganglia (BG) nuclei does not proliferate throughout the cortico-basal ganglia loop in uniform fashion; rather it can be subdivided into two distinct frequency bands, i.e. the lower beta (12-20 Hz) and upper beta (21-35 Hz). A computational model of the excitatory and inhibitory neural network that focuses on the population properties is proposed to explore the mechanism underlying the pathological beta oscillations...
January 30, 2017: Neural Networks: the Official Journal of the International Neural Network Society
https://www.readbyqxmd.com/read/28192459/differential-effects-of-ongoing-eeg-beta-and-theta-power-on-memory-formation
#12
Sebastian Scholz, Signe Luisa Schneider, Michael Rose
Recently, elevated ongoing pre-stimulus beta power (13-17 Hz) at encoding has been associated with subsequent memory formation for visual stimulus material. It is unclear whether this activity is merely specific to visual processing or whether it reflects a state facilitating general memory formation, independent of stimulus modality. To answer that question, the present study investigated the relationship between neural pre-stimulus oscillations and verbal memory formation in different sensory modalities. For that purpose, a within-subject design was employed to explore differences between successful and failed memory formation in the visual and auditory modality...
2017: PloS One
https://www.readbyqxmd.com/read/28192457/time-varying-spectral-power-of-resting-state-fmri-networks-reveal-cross-frequency-dependence-in-dynamic-connectivity
#13
Maziar Yaesoubi, Robyn L Miller, Vince D Calhoun
Brain oscillations and synchronicity among brain regions (brain connectivity) have been studied in resting-state (RS) and task-induced settings. RS-connectivity which captures brain functional integration during an unconstrained state is shown to vary with the frequency of oscillations. Indeed, high temporal resolution modalities have demonstrated both between and cross-frequency connectivity spanning across frequency bands such as theta and gamma. Despite high spatial resolution, functional magnetic resonance imaging (fMRI) suffers from low temporal resolution due to modulation with slow-varying hemodynamic response function (HRF) and also relatively low sampling rate...
2017: PloS One
https://www.readbyqxmd.com/read/28188912/characterization-of-neural-entrainment-to-speech-with-and-without-slow-spectral-energy-fluctuations-in-laminar-recordings-in-monkey-a1
#14
Benedikt Zoefel, Jordi Costa-Faidella, Peter Lakatos, Charles E Schroeder, Rufin VanRullen
Neural entrainment, the alignment between neural oscillations and rhythmic stimulation, is omnipresent in current theories of speech processing - nevertheless, the underlying neural mechanisms are still largely unknown. Here, we hypothesized that laminar recordings in non-human primates provide us with important insight into these mechanisms, in particular with respect to processing in cortical layers. We presented one monkey with human everyday speech sounds and recorded neural (as current-source density, CSD) oscillations in primary auditory cortex (A1)...
February 7, 2017: NeuroImage
https://www.readbyqxmd.com/read/28188217/hebbian-spike-timing-dependent-plasticity-at-the-cerebellar-input-stage
#15
M Sgritta, F Locatelli, T Soda, F Prestori, E D'Angelo
Spike-timing dependent plasticity (STDP) is a form of long-term synaptic plasticity exploiting the time relationship between postsynaptic action potentials (AP) and EPSPs. Surprisingly enough, very little was known about STDP in the cerebellum, although it is thought to play a critical role for learning appropriate timing of actions. We speculated that low-frequency oscillations observed in the granular layer may provide a reference for repetitive EPSP/AP phase coupling. Here we show that EPSP-spike pairing at 6Hz can optimally induce STDP at the mossy fiber - granule cell synapse in rats...
February 10, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28184188/stimulus-phase-locking-of-cortical-oscillations-for-rhythmic-tone-sequences-in-rats
#16
Takahiro Noda, Tomoki Amemiya, Tomoyo I Shiramatsu, Hirokazu Takahashi
Humans can rapidly detect regular patterns (i.e., within few cycles) without any special attention to the acoustic environment. This suggests that human sensory systems are equipped with a powerful mechanism for automatically predicting forthcoming stimuli to detect regularity. It has recently been hypothesized that the neural basis of sensory predictions exists for not only what happens (predictive coding) but also when a particular stimulus occurs (predictive timing). Here, we hypothesize that the phases of neural oscillations are critical in predictive timing, and these oscillations are modulated in a band-specific manner when acoustic patterns become predictable, i...
2017: Frontiers in Neural Circuits
https://www.readbyqxmd.com/read/28177924/adapted-wavelet-transform-improves-time-frequency-representations-a-study-of-auditory-elicited-p300-like-event-related-potentials-in-rats
#17
Nelly Richard, Bettina Laursen, Morten Grupe, Asbjørn M Drewes, Carina Graversen, Helge B D Sørensen, Jesper F Bastlund
OBJECTIVE: Active auditory oddball paradigms are simple tone discrimination tasks used to study the P300 deflection of event-related potentials (ERPs). These ERPs may be quantified by time-frequency analysis. As auditory stimuli cause early high frequency and late low frequency ERP oscillations, the continuous wavelet transform (CWT) is often chosen for decomposition due to its multi-resolution properties. However, as the conventional CWT traditionally applies only one mother wavelet to represent the entire spectrum, the time-frequency resolution is not optimal across all scales...
February 8, 2017: Journal of Neural Engineering
https://www.readbyqxmd.com/read/28176756/amygdala-hippocampal-dynamics-during-salient-information-processing
#18
Jie Zheng, Kristopher L Anderson, Stephanie L Leal, Avgusta Shestyuk, Gultekin Gulsen, Lilit Mnatsakanyan, Sumeet Vadera, Frank P K Hsu, Michael A Yassa, Robert T Knight, Jack J Lin
Recognizing motivationally salient information is critical to guiding behaviour. The amygdala and hippocampus are thought to support this operation, but the circuit-level mechanism of this interaction is unclear. We used direct recordings in the amygdala and hippocampus from human epilepsy patients to examine oscillatory activity during processing of fearful faces compared with neutral landscapes. We report high gamma (70-180 Hz) activation for fearful faces with earlier stimulus evoked onset in the amygdala compared with the hippocampus...
February 8, 2017: Nature Communications
https://www.readbyqxmd.com/read/28170348/thermal-conductivity-calculation-of-nano-suspensions-using-green-kubo-relations-with-reduced-artificial-correlations
#19
Murali Gopal Muraleedharan, Dilip Sundaram, Asegun Henry, Vigor Yang
The presence of artificial correlations associated with Green-Kubo (GK) thermal conductivity calculations is investigated. The thermal conductivity of nano-suspensions is calculated by equilibrium molecular dynamics (EMD) simulations using GK relations. Calculations are first performed for a single alumina (Al2O3) nanoparticle dispersed in a water medium. For a particle size of 1 nm and volume fraction of 9%, results show enhancements as high as 235%, which is much higher than the Maxwell model predictions...
February 7, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28166228/rapid-turnover-of-dnaa-at-replication-origin-regions-contributes-to-initiation-control-of-dna-replication
#20
Katrin Schenk, Ana B Hervás, Thomas C Rösch, Marc Eisemann, Bernhard A Schmitt, Stephan Dahlke, Luise Kleine-Borgmann, Seán M Murray, Peter L Graumann
DnaA is a conserved key regulator of replication initiation in bacteria, and is homologous to ORC proteins in archaea and in eukaryotic cells. The ATPase binds to several high affinity binding sites at the origin region and upon an unknown molecular trigger, spreads to several adjacent sites, inducing the formation of a helical super structure leading to initiation of replication. Using FRAP analysis of a functional YFP-DnaA allele in Bacillus subtilis, we show that DnaA is bound to oriC with a half-time of 2...
February 6, 2017: PLoS Genetics
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