Weakness of short-term synchronization among respiratory nerve activities during fictive vomiting

1992 ◽  
Vol 263 (2) ◽  
pp. R339-R347 ◽  
Author(s):  
M. I. Cohen ◽  
A. D. Miller ◽  
R. Barnhardt ◽  
C. F. Shaw
Keyword(s):  
Time Scale ◽  
High Frequency ◽  
Pattern Generator ◽  
High Frequency Oscillation ◽  
Short Time Scale ◽  
Coherence Analysis ◽  
Frequency Range ◽  
Frequency Oscillation ◽  
Short Term ◽  
Short Time

In decerebrate, paralyzed cats, phrenic (PHR) and lumbar abdominal (ABD) nerve discharges during both neural respiration and fictive vomiting (FV) were subjected to spectral and coherence analyses. During respiration, PHR discharge exhibited high-frequency oscillation (HFO), manifested as a narrow spectral peak (range 57-90 Hz) in autospectra and left-right coherence spectra. During FV, the following occurred: 1) the HFO peak disappeared and was replaced by a broad peak with higher modal frequency (range 84-120 Hz), indicating elimination of inputs from the medullary inspiratory pattern generator. 2) Left-right PHR coherence spectra had no distinct peaks, indicating that correlations between opposite PHR discharges were now not frequency specific. 3) Although ABD and PHR autospectra were similar, PHR-ABD coherences were near zero, indicating lack of common inputs on a short time scale. 4) Nonzero coherences between ABD nerves were confined to ipsilateral pairs. Thus coherence analysis indicates that the outputs of the vomiting pattern generator are temporally dispersed on a short time scale and are not necessarily common to different motoneuron populations.

Population and Unit Synchrony of Fast Rhythms in Expiratory Recurrent Laryngeal Discharges

2000 ◽  
Vol 84 (2) ◽  
pp. 1098-1102 ◽  
Author(s):  
Wu-Xin Huang ◽  
Morton I. Cohen
Keyword(s):  
High Frequency ◽  
Membrane Properties ◽  
High Frequency Oscillation ◽  
Frequency Range ◽  
Frequency Oscillation ◽  
Medium Frequency ◽  
Value Range ◽  
Neural Interactions ◽  
Unit Unit ◽  
Fast Rhythm

In a decerebrate, vagotomized, gallamine-paralyzed cat that had a prominent bilaterally coherent fast rhythm (50 Hz) in expiratory (E) recurrent laryngeal (RL) nerve discharges, recordings were taken of the firing of nine RL E fibers. This rhythm (called E high-frequency oscillation or EHFO) was seen as a sharp peak in all unit autospectra, all unit-nerve coherence spectra (value range 0.39–0.91), and all unit-unit coherence spectra (value range 0.27–0.85). In addition, 8/9 units had a sharp autospectral peak in a lower frequency range (19–35 Hz) called E medium-frequency oscillation (EMFO), but there was no coherence at this frequency between signal pairs (unit-unit, unit-nerve, nerve-nerve). The MFOs are specific for each unit and are considered to arise from asynchronous inputs and membrane properties. The HFOs are considered to arise from widespread network interactions that produce a common (correlated) rhythm in virtually all neurons of the RL E network. These phenomena suggest the use of the RL E network as a model system for analyzing rhythmic neural interactions.

scholarly journals The Mathematical Analysis On The Effect Of Strong Nonlinearity On Steady-State Self-Focusing And Filamentation Of Whistlers In A Plasma

2016 ◽  
Vol 5 (1) ◽  
pp. 18
Author(s):  
Ghanshyam Rai
Keyword(s):  
Time Scale ◽  
High Frequency ◽  
Small Scale ◽  
Nonuniform Heating ◽  
Short Time Scale ◽  
Strong Nonlinearity ◽  
Self Focusing ◽  
Long Time ◽  
Short Time ◽  
Very High

<div><p><em>A high-power Gaussian Whistler propagating in a magnatoplasma becomes self-focused because of (i) ponderomotive force and (ii) nonuniform heating nonlinearities (i) being dominant for t &lt;&lt; T and (ii) being dominant for t &gt; t<sub>E</sub>. On short time scale (t &lt;&lt; t<sub>E</sub> ) whistlers of all frequencies can be focused (the self – focusing length is very large for ω= </em><em> /2 and decreases rapidly on both sides), whereas on the long time scale (t &gt; t<sub>E</sub>) only high frequency whistlers (ω&gt; </em><em> /2) are focused. At very high powers the plasma is depleted almost completely from the axial region and self-focusing does not occur, rather, defocusing takes place. </em></p><p><em>            A plane uniform whistler of high intensity is seen to be unstable for small scale fluctuations, i.e., it must break up into filaments in course of it propagation. The growth rate increases with decreasing scale length of perturbation and is seen to be a saturating function of power density of the beam. </em></p></div>

Possible network interactions indicated by bilaterally coherent fast rhythms in expiratory recurrent laryngeal nerve discharges

1993 ◽  
Vol 70 (5) ◽  
pp. 2192-2196 ◽  
Author(s):  
W. X. Huang ◽  
C. N. Christakos ◽  
M. I. Cohen ◽  
Q. He
Keyword(s):  
High Frequency ◽  
Laryngeal Nerve ◽  
Short Time Scale ◽  
Coherence Analysis ◽  
High Frequency Oscillations ◽  
Prolonged Duration ◽  
Almost All ◽  
Short Time ◽  
Two Sides ◽  
Pulmonary Stretch Receptor

1. In a search for correlated fast rhythms in recurrent laryngeal (RL) expiratory (E) activities, we performed spectral and coherence analysis on bilateral RL nerve discharges in 54 midcollicular decerebrate, paralyzed cats. 2. Inspiratory (I) RL activities showed in almost all cases high-frequency oscillations (HFO, range 50-100 Hz) that were bilaterally coherent and also coherent to HFOs in phrenic (PHR) activities. In contrast, bilaterally coherent rhythms (range 24-54 Hz) in RLE discharges were found in only a fraction of the cats (6/54); in the other cats (48/54) such coherences were absent even though the auto-spectra showed the presence of similar fast rhythms on the two sides. The bilateral RLE coherences were associated with increased amplitude and prolonged duration of RLE activity, such as occurred following removal of phasic pulmonary stretch receptor inputs by vagotomy or by no-inflation. 3. Thus, although coherent fast rhythms are uncommon in RLE discharges, their occurrence under some conditions indicates the presence of short-time-scale interactions between neurons involved in this activity. This suggests that such rhythms are a general feature of neural networks.

scholarly journals Origin of Blazar Activity

1999 ◽  
Vol 194 ◽  
pp. 256-268
Author(s):  
M. M. Romanova
Keyword(s):  
Magnetic Field ◽  
Black Hole ◽  
Energy Spectrum ◽  
Magnetic Fields ◽  
Time Scale ◽  
High Frequency ◽  
Short Time Scale ◽  
Poynting Flux ◽  
Electron Positron ◽  
Short Time

Models of Blazars based on the propagation of finite discontinuities or fronts in the Poynting flux jet from the innermost regions of an accretion disk around a black hole are discussed. Such fronts may be responsible for short time–scale (from less than hours to days) flares in different wavebands from high frequency radioband to TeV, with delay in low radio frequencies as a result of synchrotron self-absorption. The cases of magnetic fields of one and opposite polarities across the front are investigated. We find that annihilation of magnetic field in the front leads to higher energy spectrum of leptons and possibility of strong TeV flares. Electron–positron pairs form in most cases as a result of interaction between numerous synchrotron photons and SSC photons, and constitute the majority species, compared with the ions at subparsec scales. Frequent weak outbursts may be responsible for flickering core radiation in all wavebands, while the stronger outbursts may be observed as short time–scale flares.

High-Frequency Oscillation and Chronic Lung Disease in Very Low Birth Weight Infants

PEDIATRICS ◽  
2001 ◽  
Vol 108 (1) ◽  
pp. 212-214
Author(s):  
J. P. Shenai; ◽  
P. Rimensberger; ◽  
U. Thome ◽  
F. Pohlandt; ◽  
P. Rimensberger
Keyword(s):  
Birth Weight ◽  
Low Birth Weight ◽  
Lung Disease ◽  
Chronic Lung Disease ◽  
High Frequency ◽  
Very Low Birth Weight ◽  
High Frequency Oscillation ◽  
Frequency Oscillation ◽  
Low Birth Weight Infants

An Alternative Test Using Algal Cultures for Testing Chemicals for Toxicity

1993 ◽  
Vol 21 (2) ◽  
pp. 196-201
Author(s):  
Søren Achim Nielsen ◽  
Thomas Hougaard
Keyword(s):  
Size Distribution ◽  
Mitotic Activity ◽  
Time Scale ◽  
Test System ◽  
Short Time Scale ◽  
Toxic Substances ◽  
Alternative Test ◽  
Short Time ◽  
Algal Cultures ◽  
Test Cultures

An alternative test is presented, in which algal cultures are used for testing toxic substances. This test system is based on variations in the size distribution of cells in test cultures as a measurement of growth. Thus, inhibition of mitotic activity is used as a measurement for toxic effects. The test can be performed on a short time-scale and is very sensitive to even weak toxic doses.

scholarly journals A Comprehensive Investigation on High-Frequency Oscillation in DC Microgrid

IEEE Access ◽  
2021 ◽  
pp. 1-1
Author(s):  
Mohammad Habibullah ◽  
Nadarajah Mithulananthan ◽  
Krischonme Bhumkittipich ◽  
Mohammad Amin
Keyword(s):  
High Frequency ◽  
High Frequency Oscillation ◽  
Frequency Oscillation ◽  
Comprehensive Investigation ◽  
Dc Microgrid
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