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https://www.readbyqxmd.com/read/29161621/human-subthalamic-oscillatory-dynamics-following-somatosensory-stimulation
#1
Saskia Elben, Carlos Trenado, Jan Vesper, Alfons Schnitzler, Lars Wojtecki
OBJECTIVE: Electrical median nerve somatosensory stimulation leads to a distinct modulation of cortical oscillations. Initial high frequency and gamma augmentation, as well as modulation of beta and alpha oscillations have been reported. We aimed at investigating the involvement of the subthalamic nucleus in somatosensory processing by means of local field potential recordings, since recordings during passive movements and peripheral somatosensory stimulation have suggested a prominent role...
October 28, 2017: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
https://www.readbyqxmd.com/read/29151607/zeeman-effect-in-sulfur-monoxide-a-tool-to-probe-magnetic-fields-in-star-forming-regions
#2
Gabriele Cazzoli, Valerio Lattanzi, Sonia Coriani, Jürgen Gauss, Claudio Codella, Andrés Asensio Ramos, José Cernicharo, Cristina Puzzarini
Context: Magnetic fields play a fundamental role in star formation processes and the best method to evaluate their intensity is to measure the Zeeman effect of atomic and molecular lines. However, a direct measurement of the Zeeman spectral pattern from interstellar molecular species is challenging due to the high sensitivity and high spectral resolution required. So far, the Zeeman effect has been detected unambiguously in star forming regions for very few non-masing species, such as OH and CN...
September 2017: Astronomy and Astrophysics
https://www.readbyqxmd.com/read/29147146/relationships-between-short-and-fast-brain-timescales
#3
Eva Déli, Arturo Tozzi, James F Peters
Brain electric activity exhibits two important features: oscillations with different timescales, characterized by diverse functional and psychological outcomes, and a temporal power law distribution. In order to further investigate the relationships between low- and high- frequency spikes in the brain, we used a variant of the Borsuk-Ulam theorem which states that, when we assess the nervous activity as embedded in a sphere equipped with a fractal dimension, we achieve two antipodal points with similar features (the slow and fast, scale-free oscillations)...
December 2017: Cognitive Neurodynamics
https://www.readbyqxmd.com/read/29145567/influence-of-airflow-rate-and-stimulus-concentration-on-olfactory-event-related-potentials-oerp-in-humans
#4
Pengfei Han, Valentin A Schriever, Per Peters, Heidi Olze, Florian C Uecker, Thomas Hummel
Although the association between odor concentration and olfactory event-related potential (OERP) has been studied, less is known about the influence of airflow on OERP. The aim of this study was to investigate the influence of airflow rate and stimulus concentration on OERP in humans. EEG data were collected from young healthy volunteers (n=17) in separate sessions where 2-phenylethanol (PEA) was delivered in the following conditions: 8L/min 50%v/v, 8L/min 30%v/v, 4L/min 100%v/v and 4L/min 60%v/v. Odor concentrations are referred to the %v/v achieved with air dilution and was not measured in the nose...
November 14, 2017: Chemical Senses
https://www.readbyqxmd.com/read/29140973/a-coupled-oscillator-model-of-olfactory-bulb-gamma-oscillations
#5
Guoshi Li, Thomas A Cleland
The olfactory bulb transforms not only the information content of the primary sensory representation, but also its underlying coding metric. High-variance, slow-timescale primary odor representations are transformed by bulbar circuitry into secondary representations based on principal neuron spike patterns that are tightly regulated in time. This emergent fast timescale for signaling is reflected in gamma-band local field potentials, presumably serving to efficiently integrate olfactory sensory information into the temporally regulated information networks of the central nervous system...
November 15, 2017: PLoS Computational Biology
https://www.readbyqxmd.com/read/29131954/ultrafast-wiggling-and-jiggling-ir2-1-8-diisocyanomenthane-4-2
#6
Martin Pizl, Bryan M Hunter, Gregory M Greetham, Michael Towrie, Stanislav Zalis, Harry B Gray, Antonin Vlcek
Binuclear complexes of d8 metals (PtII, IrI, RhI, ) exhibit diverse photonic behavior including dual emission from relatively long-lived singlet and triplet excited states, as well as photochemical energy-, electron-, and atom transfer. Time-resolved optical spectroscopic and X-ray studies have revealed the behavior of the dimetallic core, confirming that M-M bonding is strengthened upon d*p excitation. We report the bridging ligand dynamics of Ir2(1,8-diisocyanomenthane)42+ (Ir(dimen)), investigated by fs-ns time-resolved IR spectroscopy (TRIR) in the region of CN stretching vibrations, (CN), 2000-2300 cm-1...
November 13, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/29131193/frequency-and-timing-stability-of-an-airborne-injection-seeded-nd-yag-laser-system-for-direct-detection-wind-lidar
#7
Christian Lemmerz, Oliver Lux, Oliver Reitebuch, Benjamin Witschas, Christian Wührer
We report on the design and performance of the laser deployed in the airborne demonstrator Doppler wind lidar for the Aeolus mission of the European Space Agency (ESA). The all-solid-state, diode-pumped and frequency-tripled Nd:YAG laser is realized as a master oscillator power amplifier (MOPA) system, generating 60 mJ of single-frequency pulses at 355 nm wavelength, 50 Hz repetition rate and 20 ns pulse duration. For the measurement of the Doppler frequency shift over several accumulated laser shots, the frequency stability of the laser is of crucial importance...
November 10, 2017: Applied Optics
https://www.readbyqxmd.com/read/29125416/gamma-oscillations-in-the-somatosensory-thalamus-of-a-patient-with-a-phantom-limb-case-report
#8
Diellor Basha, Jonathan O Dostrovsky, Suneil K Kalia, Mojgan Hodaie, Andres M Lozano, William D Hutchison
The amputation of an extremity is commonly followed by phantom sensations that are perceived to originate from the missing limb. The mechanism underlying the generation of these sensations is still not clear although the development of abnormal oscillatory bursting in thalamic neurons may be involved. The theory of thalamocortical dysrhythmia implicates gamma oscillations in phantom pathophysiology although this rhythm has not been previously observed in the phantom limb thalamus. In this study, the authors report the novel observation of widespread 38-Hz gamma oscillatory activity in spike and local field potential recordings obtained from the ventral caudal somatosensory nucleus of the thalamus (Vc) of a phantom limb patient undergoing deep brain stimulation (DBS) surgery...
November 10, 2017: Journal of Neurosurgery
https://www.readbyqxmd.com/read/29122515/xer1-independent-mechanisms-of-vpma-phase-variation-in-mycoplasma-agalactiae-are-triggered-by-vpma-specific-antibodies
#9
Stefan Czurda, Shivanand Manjunath Hegde, Renate Rosengarten, Rohini Chopra-Dewasthaly
Despite their small genomes mycoplasmas maintain large multigene families devoted to surface antigenic variation. Although implicated as important factors for mycoplasma pathogenicity and persistence, the role of these antigenic switches in host immune evasion has never been unequivocally proven in these minimalist microbes. Mycoplasma agalactiae exhibits antigenic variation due to Xer1-mediated site-specific DNA inversions of vpma genes encoding abundant multiple surface lipoproteins. To evaluate the biological significance of Vpma oscillations the xer1 recombinase gene has been disrupted in earlier studies to abolish Vpma switching and to generate stable phase-locked mutants (PLMs) steadily expressing a single Vpma product...
November 6, 2017: International Journal of Medical Microbiology: IJMM
https://www.readbyqxmd.com/read/29122445/a-method-for-the-topographical-identification-and-quantification-of-high-frequency-oscillations-in-intracranial-electroencephalography-recordings
#10
Zachary J Waldman, Shoichi Shimamoto, Inkyung Song, Iren Orosz, Anatol Bragin, Itzhak Fried, Jerome Engel, Richard Staba, Michael R Sperling, Shennan A Weiss
OBJECTIVE: To develop a reliable software method using a topographic analysis of time-frequency plots to distinguish ripple (80-200 Hz) oscillations that are often associated with EEG sharp waves or spikes (RonS) from sinusoid-like waveforms that appear as ripples but correspond with digital filtering of sharp transients contained in the wide bandwidth EEG. METHODS: A custom algorithm distinguished true from false ripples in one second intracranial EEG (iEEG) recordings using wavelet convolution, identifying contours of isopower, and categorizing these contours into sets of open or closed loop groups...
October 21, 2017: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
https://www.readbyqxmd.com/read/29118193/duration-analysis-using-matching-pursuit-algorithm-reveals-longer-bouts-of-gamma-rhythm
#11
Subhash Chandran Ks, Chandra Sekhar Seelamantula, Supratim Ray
The gamma rhythm (30 to 80 Hz), often associated with high-level cortical functions, is believed to provide a temporal reference frame for spiking activity, for which it should have a stable center frequency and linear phase for an extended duration. However, recent studies that have estimated the power and phase of gamma as a function of time suggest that gamma occurs in short bursts and lacks the temporal structure required to act as a reference frame. Here we show that the bursty appearance of gamma arises from the variability in the spectral estimator used in these studies...
November 8, 2017: Journal of Neurophysiology
https://www.readbyqxmd.com/read/29115282/fast-and-slow-thermal-processes-in-harmonic-scalar-lattices
#12
Vitaly A Kuzkin, Anton M Krivtsov
An approach for analytical description of thermal processes in harmonic lattices is presented. We cover longitudinal and transverse vibrations of chains and out-of-plane vibrations of two-dimensional lattices with interactions of an arbitrary number of neighbors. Motion of each particle is governed by a single scalar equation and therefore the notion ``scalar lattice'' is used. Evolution of initial temperature field in an infinite lattice is investigated. An exact equation describing the evolution is derived...
November 8, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/29113719/utilization-of-independent-component-analysis-for-accurate-pathological-ripple-detection-in-intracranial-eeg-recordings-recorded-extra-and-intra-operatively
#13
Shoichi Shimamoto, Zachary J Waldman, Iren Orosz, Inkyung Song, Anatol Bragin, Itzhak Fried, Jerome Engel, Richard Staba, Ashwini Sharan, Chengyuan Wu, Michael R Sperling, Shennan A Weiss
OBJECTIVE: To develop and validate a detector that identifies ripple (80-200 Hz) events in intracranial EEG (iEEG) recordings in a referential montage and utilizes independent component analysis (ICA) to eliminate or reduce high-frequency artifact contamination. Also, investigate the correspondence of detected ripples and the seizure onset zone (SOZ). METHODS: iEEG recordings from 16 patients were first band-pass filtered (80-600 Hz) and Infomax ICA was next applied to derive the first independent component (IC1)...
October 25, 2017: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
https://www.readbyqxmd.com/read/29112634/baroreflex-sensitivity-and-blood-pressure-variability-can-help-in-understanding-the-different-response-to-therapy-during-acute-phase-of-septic-shock
#14
Marta Carrara, Bernardo Bollen Pinto, Giuseppe Baselli, Karim Bendjelid, Manuela Ferrario
BACKGROUND: Mean values of hemodynamic variables are poorly effective in evaluating an actual recovery of the short-term autonomic mechanisms for blood pressure (BP) and heart rate (HR) regulation. The aim of this work is to analyze the responses to therapy in the early phase of septic shock in order to verify possible associations between BP recovery and BP autonomic control. METHODS: This is an ancillary study from the multicenter prospective observational trial Shockomics (NCT02141607)...
November 6, 2017: Shock
https://www.readbyqxmd.com/read/29111591/magnetoencephalographic-imaging-of-ictal-high-frequency-oscillations-80-200%C3%A2-hz-in-pharmacologically-resistant-focal-epilepsy
#15
Jayabal Velmurugan, Srikantan S Nagarajan, Narayanan Mariyappa, Shankar G Ravi, Kandavel Thennarasu, Ravindranadh C Mundlamuri, Kenchaiah Raghavendra, Rose Dawn Bharath, Jitender Saini, Arimappamagan Arivazhagan, Jamuna Rajan, Anita Mahadevan, Malla B Rao, Parthasarathy Satishchandra, Sanjib Sinha
OBJECTIVE: Specificity of ictal high-frequency oscillations (HFOs) in identifying epileptogenic abnormality is significant, compared to the spikes and interictal HFOs. The objectives of the study were to detect and to localize ictal HFOs by magnetoencephalography (MEG) for identifying the seizure onset zone (SOZ), evaluate the cortical excitability from preictal to ictal transition, and establish HFO concordance rates with other modalities and postsurgical resection. METHODS: Sixty-seven patients with drug-resistant epilepsy had at least 1 spontaneous seizure each during MEG acquisition, and analysis was carried out on 20 seizures from 20 patients...
November 7, 2017: Epilepsia
https://www.readbyqxmd.com/read/29107088/intrinsic-frequency-specific-brain-networks-for-identification-of-mci-individuals-using-resting-state-fmri
#16
Long Qian, Li Zheng, Yuqing Shang, Yaoyu Zhang, Yi Zhang
Numerous brain oscillations are well organized into several brain rhythms to support complex brain activities within distinct frequency bands. These rhythms temporally coexist in the same or different brain areas and may interact with each other with specific properties and physiological functions. However, the identification and evaluation of these various brain rhythms derived from BOLD-fMRI signals are obscure. To address this issue, we introduced a data-driven method named Complementary Ensemble Empirical Mode Decomposition (CEEMD) to automatically decompose the BOLD oscillations into several brain rhythms within distinct frequency bands...
October 26, 2017: Neuroscience Letters
https://www.readbyqxmd.com/read/29106374/the-rate-of-transient-beta-frequency-events-predicts-behavior-across-tasks-and-species
#17
Hyeyoung Shin, Robert Law, Shawn Tsutsui, Christopher I Moore, Stephanie R Jones
Beta oscillations (15-29Hz) are among the most prominent signatures of brain activity. Beta power is predictive of healthy and abnormal behaviors, including perception, attention and motor action. In non-averaged signals, beta can emerge as transient high-power 'events'. As such, functionally relevant differences in averaged power across time and trials can reflect changes in event number, power, duration, and/or frequency span. We show that functionally relevant differences in averaged beta power in primary somatosensory neocortex reflect a difference in the number of high-power beta events per trial, i...
November 6, 2017: ELife
https://www.readbyqxmd.com/read/29104149/spatial-attention-modulates-visual-gamma-oscillations-across-the-human-ventral-stream
#18
Lorenzo Magazzini, Krish D Singh
Oscillatory synchronization in the gamma frequency range has been proposed as a neuronal mechanism to prioritize processing of relevant stimuli over competing ones. Recent studies in animals found that selective spatial attention enhanced gamma-band synchronization in high-order visual areas (V4) and increased the gamma peak frequency in V1. The existence of such mechanisms in the human visual system is yet to be fully demonstrated. In this study, we used MEG, in combination with an optimised stimulus design, to record visual gamma oscillations from human early visual cortex, while participants performed a visuospatial attention cueing task...
November 2, 2017: NeuroImage
https://www.readbyqxmd.com/read/29103999/improving-the-quality-of-combined-eeg-tms-neural-recordings-introducing-the-coil-spacer
#19
K L Ruddy, D G Woolley, D Mantini, J H Balsters, N Enz, N Wenderoth
BACKGROUND: In the last decade, interest in combined transcranial magnetic stimulation (TMS) and electroencephalography (EEG) approaches has grown substantially. Aside from the obvious artifacts induced by the magnetic pulses themselves, separate and more sinister signal disturbances arise as a result of contact between the TMS coil and EEG electrodes. NEW METHOD: Here we profile the characteristics of these artifacts and introduce a simple device - the coil spacer - to provide a platform allowing physical separation between the coil and electrodes during stimulation...
November 6, 2017: Journal of Neuroscience Methods
https://www.readbyqxmd.com/read/29101860/correlation-between-extreme-fear-and-focal-cortical-dysplasia-in-anterior-cingulate-gyrus-evidence-from-a-surgical-case-of-refractory-epilepsy
#20
Liang Qiao, Tao Yu, Duanyu Ni, Xueyuan Wang, Cuiping Xu, Chang Liu, Guojun Zhang, Yongjie Li
Localizing the semiology of ictal fear and seizure onset in epilepsy patients is commonly challenging due to limited value of routine electroencephalography (EEG) and very few surgical attempts. Here we reported a case of refractory epilepsy characterized by aura of extreme fear and hypermotor seizures, in which the left (dominant hemisphere) anterior cingulate gyrus (ACG) was determined to be the epileptogenic zone (EZ) through multiple modalities of presurgical evaluation including analysis of high frequency oscillation on intracranial EEG...
October 31, 2017: Clinical Neurology and Neurosurgery
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