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https://www.readbyqxmd.com/read/28069165/on-the-quantification-and-visualization-of-transient-periodic-instabilities-in-pulsatile-flows
#1
Muhammad Owais Khan, Christophe Chnafa, Diego Gallo, Filippo Molinari, Umberto Morbiducci, David A Steinman, Kristian Valen-Sendstad
Turbulent-like flows without cycle-to-cycle variations are more frequently being reported in studies of cardiovascular flows. The associated stimuli might be of mechanobiological relevance, but how to quantify them objectively is not obvious. Classical Reynolds decomposition, where the flow is separated into mean and fluctuating velocity components, is not applicable as the phase-average is zero. We therefore expanded on established techniques and present the idea, analogous to Reynolds decomposition, to decompose a flow with transient instabilities into low- versus high frequency components, respectively, to discriminate flow instabilities from the underlying cardiac pulsatility...
December 31, 2016: Journal of Biomechanics
https://www.readbyqxmd.com/read/28053151/optimized-temporal-pattern-of-brain-stimulation-designed-by-computational-evolution
#2
David T Brocker, Brandon D Swan, Rosa Q So, Dennis A Turner, Robert E Gross, Warren M Grill
Brain stimulation is a promising therapy for several neurological disorders, including Parkinson's disease. Stimulation parameters are selected empirically and are limited to the frequency and intensity of stimulation. We varied the temporal pattern of deep brain stimulation to ameliorate symptoms in a parkinsonian animal model and in humans with Parkinson's disease. We used model-based computational evolution to optimize the stimulation pattern. The optimized pattern produced symptom relief comparable to that from standard high-frequency stimulation (a constant rate of 130 or 185 Hz) and outperformed frequency-matched standard stimulation in a parkinsonian rat model and in patients...
January 4, 2017: Science Translational Medicine
https://www.readbyqxmd.com/read/28041911/disinhibition-of-the-intergeniculate-leaflet-network-in-the-wag-rij-rat-model-of-absence-epilepsy
#3
Lukasz Chrobok, Katarzyna Palus, Jagoda Stanislawa Jeczmien-Lazur, Anna Chrzanowska, Mariusz Kepczynski, Marian Henryk Lewandowski
The intergeniculate leaflet (IGL) of the thalamus is a retinorecipient structure implicated in orchestrating circadian rhythmicity. The IGL network is highly GABAergic and consists mainly of neuropeptide Y-synthesising and enkephalinergic neurons. A high density of GFAP-immunoreactive astrocytes has been observed in the IGL, with a probable function in guarding neuronal inhibition. Interestingly, putatively enkephalinergic IGL neurons generate action potentials with an infra-slow oscillatory (ISO) pattern in vivo in urethane anesthetised Wistar rats, under light-on conditions only...
December 30, 2016: Experimental Neurology
https://www.readbyqxmd.com/read/28040004/oscillatory-fluid-flow-in-deformable-tubes-implications-for-pore-scale-hydromechanics-from-comparing-experimental-observations-with-theoretical-predictions
#4
Patrick Kurzeja, Holger Steeb, Marc A Strutz, Jörg Renner
Oscillatory flow of four fluids (air, water, two aqueous sodium-tungstate solutions) was excited at frequencies up to 250 Hz in tubes of two materials (steel, silicone) covering a wide range in length, diameter, and thickness. The hydrodynamical response was characterized by phase shift and amplitude ratio between pressures in an upstream (pressure excitation) and a downstream reservoir connected by the tubes. The resulting standing flow waves reflect viscosity-controlled diffusive behavior and inertia-controlled wave behavior for oscillation frequencies relatively low and high compared to Biot's critical frequency, respectively...
December 2016: Journal of the Acoustical Society of America
https://www.readbyqxmd.com/read/28031220/pathological-ponto-cerebello-thalamo-cortical-activations-in-primary-orthostatic-tremor-during-lying-and-stance
#5
Florian Schöberl, Katharina Feil, Guoming Xiong, Peter Bartenstein, Christian la Fougére, Klaus Jahn, Thomas Brandt, Michael Strupp, Marianne Dieterich, Andreas Zwergal
Primary orthostatic tremor is a rare neurological disease characterized mainly by a high frequency tremor of the legs while standing. The aim of this study was to identify the common core structures of the oscillatory circuit in orthostatic tremor and how it is modulated by changes of body position. Ten patients with orthostatic tremor and 10 healthy age-matched control subjects underwent a standardized neurological and neuro-ophthalmological examination including electromyographic and posturographic recordings...
January 2017: Brain: a Journal of Neurology
https://www.readbyqxmd.com/read/28003411/dorsal-versus-ventral-differences-in-fast-up-state-associated-oscillations-in-the-medial-prefrontal-cortex-mpfc-of-the-urethane-anaesthetised-rat
#6
Sabine Gretenkord, Adrian Rees, Miles A Whittington, Sarah E Gartside, Fiona E N LeBeau
Cortical slow oscillations (0.1 - 1 Hz), which may play a role in memory consolidation, are a hallmark of non-rapid eye movement (NREM) sleep and also occur under anaesthesia. During slow oscillations the neuronal network generates faster oscillations on the active Up-states and these nested oscillations are particularly prominent in the PFC. In rodents the mPFC consists of several subregions: anterior cingulate cortex (ACC), prelimbic (PrL), infralimbic (IL) and dorsal peduncular cortices (DP). Although each region has a distinct anatomy and function, it is not known whether slow or fast network oscillations differ between subregions in vivo...
December 21, 2016: Journal of Neurophysiology
https://www.readbyqxmd.com/read/27998287/the-thalamic-mglur1-plc%C3%AE-4-pathway-is-critical-in-sleep-architecture
#7
Joohyeon Hong, Jungryun Lee, Kiyeong Song, Go Eun Ha, Yong Ryoul Yang, Ji Su Ma, Masahiro Yamamoto, Hee-Sup Shin, Pann-Ghill Suh, Eunji Cheong
The transition from wakefulness to a nonrapid eye movement (NREM) sleep state at the onset of sleep involves a transition from low-voltage, high-frequency irregular electroencephalography (EEG) waveforms to large-amplitude, low-frequency EEG waveforms accompanying synchronized oscillatory activity in the thalamocortical circuit. The thalamocortical circuit consists of reciprocal connections between the thalamus and cortex. The cortex sends strong excitatory feedback to the thalamus, however the function of which is unclear...
December 21, 2016: Molecular Brain
https://www.readbyqxmd.com/read/27965146/movement-related-beta-oscillations-show-high-intra-individual-reliability
#8
Svenja Espenhahn, Archy O de Berker, Bernadette C M van Wijk, Holly E Rossiter, Nick S Ward
Oscillatory activity in the beta frequency range (15-30Hz) recorded from human sensorimotor cortex is of increasing interest as a putative biomarker of motor system function and dysfunction. Despite its increasing use in basic and clinical research, surprisingly little is known about the test-retest reliability of spectral power and peak frequency measures of beta oscillatory signals from sensorimotor cortex. Establishing that these beta measures are stable over time in healthy populations is a necessary precursor to their use in the clinic...
December 10, 2016: NeuroImage
https://www.readbyqxmd.com/read/27940307/comparison-of-oscillatory-activity-in-subthalamic-nucleus-in-parkinson-s-disease-and-dystonia
#9
Xinyi Geng, Jianguo Zhang, Yin Jiang, Keyoumars Ashkan, Thomas Foltynie, Patricia Limousin, Ludvic Zrinzo, Alexander Green, Tipu Aziz, Peter Brown, Shouyan Wang
OBJECTIVES: Deep brain stimulation (DBS) of the subthalamic nucleus (STN) has been successfully used to treat both Parkinson's disease (PD) and dystonia. Local field potentials (LFPs) recorded from the STN of PD patients demonstrate prominent beta frequency band activity. It is unclear whether such activity occurs in the STN in dystonia, and, if not, whether dystonia has another distinctive neural population activity in the STN. METHODS: Twelve patients with PD, and eight patients with dystonia underwent DBS electrode implantation targeting the STN...
February 2017: Neurobiology of Disease
https://www.readbyqxmd.com/read/27939691/frequency-dependent-transient-effects-of-subthalamic-nucleus-deep-brain-stimulation-on-methamphetamine-induced-circling-and-neuronal-activity-in-the-hemiparkinsonian-rat
#10
Rosa Q So, George C McConnell, Warren M Grill
Methamphetamine-induced circling is used to quantify the behavioral effects of subthalamic nucleus (STN) deep brain stimulation (DBS) in hemiparkinsonian rats. We observed a frequency-dependent transient effect of DBS on circling, and quantified this effect to determine its neuronal basis. High frequency STN DBS (75-260Hz) resulted in transient circling contralateral to the lesion at the onset of stimulation, which was not sustained after the first several seconds of stimulation. Following the transient behavioral change, DBS resulted in a frequency-dependent steady-state reduction in pathological ipsilateral circling, but no change in overall movement...
December 6, 2016: Behavioural Brain Research
https://www.readbyqxmd.com/read/27927806/sleep-neurophysiological-dynamics-through-the-lens-of-multitaper-spectral-analysis
#11
REVIEW
Michael J Prerau, Ritchie E Brown, Matt T Bianchi, Jeffrey M Ellenbogen, Patrick L Purdon
During sleep, cortical and subcortical structures within the brain engage in highly structured oscillatory dynamics that can be observed in the electroencephalogram (EEG). The ability to accurately describe changes in sleep state from these oscillations has thus been a major goal of sleep medicine. While numerous studies over the past 50 years have shown sleep to be a continuous, multifocal, dynamic process, long-standing clinical practice categorizes sleep EEG into discrete stages through visual inspection of 30-s epochs...
January 2017: Physiology
https://www.readbyqxmd.com/read/27923944/membrane-oxygenator-use-with-biventricular-assist-device-facilitation-of-support-and-lung-recovery
#12
Kristen Nelson-McMillan, William J Ravekes, William R Thompson, Kristen M Brown, Larry Wolff, Rajeev S Wadia, LeAnn M McNamara, Donald H Shaffner, Ivor D Berkowitz, Marshall L Jacobs, Luca A Vricella
We present the use of a low-resistance membrane oxygenator (Quadrox D, Maquet) in series with a pulsatile right ventricular assist device (Berlin Heart EXCOR, Berlin Heart) in a patient with biventricular support who required high-frequency oscillatory ventilation (HFOV), due to refractory acute respiratory distress syndrome associated with Cytomegalovirus pneumonia. The high mean airway pressure associated with the use of HFOV resulted in a significant negative impact on left ventricular assist device (LVAD) filling that led to a combined respiratory and metabolic acidosis and the need for vasopressor support...
December 6, 2016: World Journal for Pediatric & Congenital Heart Surgery
https://www.readbyqxmd.com/read/27915117/from-intentions-to-actions-neural-oscillations-encode-motor-processes-through-phase-amplitude-and-phase-amplitude-coupling
#13
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
https://www.readbyqxmd.com/read/27910862/methylphenidate-enhances-early-stage-sensory-processing-and-rodent-performance-of-a-visual-signal-detection-task
#14
Rachel L Navarra, Brian D Clark, Andrew T Gargiulo, Barry D Waterhouse
Methylphenidate (MPH) is used clinically to treat attention-deficit/hyperactivity disorder (ADHD) and off-label as a performance enhancing agent in healthy individuals. MPH enhances catecholamine transmission via blockade of norepinephrine (NE) and dopamine (DA) reuptake transporters. However, it is not clear how this action impacts neural circuits performing cognitive and sensorimotor functions driving performance enhancement. The dorsal lateral geniculate nucleus (dLGN) is the primary thalamic relay for visual information from the retina to the cortex and is densely innervated by NE-containing fibers from the locus coeruleus (LC), a pathway known to modulate state-dependent sensory processing...
December 2, 2016: Neuropsychopharmacology: Official Publication of the American College of Neuropsychopharmacology
https://www.readbyqxmd.com/read/27903720/oscillatory-dynamics-underlying-perceptual-narrowing-of-native-phoneme-mapping-from-6-to-12-months-of-age
#15
Silvia Ortiz-Mantilla, Jarmo A Hämäläinen, Teresa Realpe-Bonilla, April A Benasich
: During the first months of life, human infants process phonemic elements from all languages similarly. However, by 12 months of age, as language-specific phonemic maps are established, infants respond preferentially to their native language. This process, known as perceptual narrowing, supports neural representation and thus efficient processing of the distinctive phonemes within the sound environment. Although oscillatory mechanisms underlying processing of native and non-native phonemic contrasts were recently delineated in 6-month-old infants, the maturational trajectory of these mechanisms remained unclear...
November 30, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/27900823/high-frequency-mechanostimulation-of-cell-adhesion
#16
Laith F Kadem, K Grace Suana, Michelle Holz, Wei Wang, Hannes Westerhaus, Rainer Herges, Christine Selhuber-Unkel
Cell adhesion is regulated by molecularly defined protein interactions and by mechanical forces, which can activate a dynamic restructuring of adhesion sites. Previous attempts to explore the response of cell adhesion to forces have been limited to applying mechanical stimuli that involve the cytoskeleton. In contrast, we here apply a new, oscillatory type of stimulus through push-pull azobenzenes. Push-pull azobenzenes perform a high-frequency, molecular oscillation upon irradiation with visible light that has frequently been applied in polymer surface relief grating...
January 2, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/27898438/rescue-therapies-for-acute-respiratory-distress-syndrome-what-to-try-first
#17
Onnen Moerer, Tommaso Tonetti, Michael Quintel
PURPOSE OF REVIEW: Severe respiratory failure due to the acute respiratory distress syndrome (ARDS) might require rescue therapy measures beyond even extended standard care to ensure adequate oxygenation and survival. This review provides a summary and assessment of treatment options that can be beneficial when the standard approach fails. RECENT FINDINGS: 'Life-threatening' conditions or refractory hypoxemia during mechanical ventilation are more a matter of personal rating than an objective diagnosis based on defined and/or unanimously agreed thresholds that would mandate the use of rescue therapies...
February 2017: Current Opinion in Critical Care
https://www.readbyqxmd.com/read/27882025/no-inhalation-in-combination-with-high-frequency-ventilation-treatment-in-the-treatment-of-neonatal-severe-respiratory-failure
#18
Xiaohui Guo, Yanfeng Sun, Jing Miao, Min Cui, Jiangbo Wang, Shuzhen Han
OBJECTIVE: To discuss over NO inhalation (iNO) in combination with high frequency ventilation treatment in relieving clinical symptoms and respiratory state of patients with neonatal severe respiratory failure. METHODS: Ninety newborns with severe respiratory failure who received treatment in our hospital were selected for this study. They were divided into research group and control group according to visiting time. Patients in the control group were given conventional treatment in combination with high-frequency oscillatory ventilation, while patients in the research group were given iNO for treatment additionally besides the treatment the same as the control group...
September 2016: Pakistan Journal of Medical Sciences Quarterly
https://www.readbyqxmd.com/read/27874934/effect-of-nitric-oxide-inhalation-for-the-treatment-of-neonatal-pulmonary-hypertension
#19
H-W Wu, Z-G Li, G Liu, G-Z Lu, H-Y Liang
OBJECTIVE: To investigate the effect of nitric oxide (NO) inhalation for the treatment of neonatal pulmonary hypertension. PATIENTS AND METHODS: Eighty-six patients with neonatal pulmonary hypertension who were treated for the first time Xuzhou Children's Hospital from January 2013 to January 2016 were selected and randomly divided into the observation group and control group, with 43 cases each. Patients in the control group were treated with high-frequency oscillatory ventilation, while those in the observation group were treated with high-frequency oscillatory ventilation combined with inhalational NO therapy...
November 2016: European Review for Medical and Pharmacological Sciences
https://www.readbyqxmd.com/read/27862666/filling-the-void-enriching-the-feature-space-of-successful-stopping
#20
René J Huster, Signe Schneider, Christina F Lavallee, Stefanie Enriquez-Geppert, Christoph S Herrmann
The ability to inhibit behavior is crucial for adaptation in a fast changing environment and is commonly studied with the stop signal task. Current EEG research mainly focuses on the N200 and P300 ERPs and corresponding activity in the theta and delta frequency range, thereby leaving us with a limited understanding of the mechanisms of response inhibition. Here, 15 functional networks were estimated from time-frequency transformed EEG recorded during processing of a visual stop signal task. Cortical sources underlying these functional networks were reconstructed, and a total of 45 features, each representing spectrally and temporally coherent activity, were extracted to train a classifier to differentiate between go and stop trials...
November 11, 2016: Human Brain Mapping
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