Coordination of the cardiac-related discharges of sympathetic nerves with different targets

1994 ◽  
Vol 267 (2) ◽  
pp. R400-R407 ◽  
Author(s):  
G. L. Gebber ◽  
S. Zhong ◽  
S. M. Barman ◽  
H. S. Orer
Keyword(s):  
Heart Rate ◽  
Coherence Function ◽  
Sympathetic Nerves ◽  
Partial Coherence ◽  
Coherence Analysis ◽  
Arterial Pulse ◽  
Nerve Activity ◽  
Multiple Routes ◽  
Rate Frequency ◽  
Decerebrate Cats

Partial coherence analysis was used to remove the influences of pulse-synchronous baroreceptor nerve activity (as reflected by the arterial pulse) on the coherence of the cardiac-related discharges of sympathetic nerve pairs in unanesthetized decerebrate cats. It can be predicted that the peak at the heart rate frequency in the ordinary coherence function relating the discharges of two nerves will be eliminated by either partialization using the arterial pulse or surgical baroreceptor denervation, if the central circuits controlling the nerves share baroreceptor inputs but are not interconnected. Contrary to this prediction, in many experiments the peak was not eliminated by partialization using the arterial pulse. Moreover, partialization often nonuniformly reduced the peaks at the heart rate frequency in the coherence functions for different nerve pairs. These results are consistent with a model of multiple routes over which baroreceptor influences are distributed to the central circuits controlling different sympathetic nerves. Specifically, we propose that the direct route from the baroreceptors to each of the central circuits is complemented by cross talk among the central circuits.

Preferential correlations of a medullary neuron's activity to different sympathetic outflows as revealed by partial coherence analysis

1995 ◽  
Vol 74 (1) ◽  
pp. 474-478 ◽  
Author(s):  
M. I. Cohen ◽  
Q. Yu ◽  
W. X. Huang
Keyword(s):  
Sympathetic Nerves ◽  
Partial Coherence ◽  
Coherence Analysis ◽  
Significant Peak ◽  
Neuron Populations ◽  
Cervical Sympathetic ◽  
Decerebrate Cats ◽  
Differential Connectivity ◽  
Coherence Spectrum ◽  
Medullary Neurons

1. In vagotomized, paralyzed, decerebrate cats, simultaneous recordings were taken from one or more sympathetic nerves [cervical sympathetic (CS), inferior cardiac (IC), splanchnic (SP)] and from medullary neurons in vasomotor-related regions. Coherence analyses were used to ascertain the presence of sympathetic rhythms (2-6 Hz or "3-Hz rhythm," 7-13 Hz or "10-Hz rhythm") that were correlated between different signals. The occurrence of a significant peak at such a frequency in a unit-nerve coherence spectrum allowed the identification of a medullary neuron as sympathetic related. 2. A serendipitous example is given of a rostral ventrolateral medullary neuron that had significant unit-nerve 10-Hz coherence peaks for three sympathetic nerves (CS, IC, SP); but, as revealed by partial coherence analysis, the unit activity's correlation with one nerve's activity could be partially or completely dependent on its correlation with other nerve activities. Thus in this case the unit-CS and unit-IC coherences at 10 Hz were completely dependent on the SP rhythm, whereas the unit-SP coherence was not significantly affected by the CS and IC rhythms. This asymmetry suggests that the neuron was preferentially connected to SP-generating medullary circuits. 3. This example indicates the strength of partial coherence analysis as a means of studying differential connectivity between medullary sympathetic-related neurons and sympathetic output neuron populations.

Coupled oscillators account for the slow rhythms in sympathetic nerve discharge and phrenic nerve activity

1997 ◽  
Vol 272 (4) ◽  
pp. R1314-R1324 ◽  
Author(s):  
S. Zhong ◽  
S. Y. Zhou ◽  
G. L. Gebber ◽  
S. M. Barman
Keyword(s):  
Phrenic Nerve ◽  
Sympathetic Nerve ◽  
Coupled Oscillators ◽  
Sympathetic Nerves ◽  
Partial Coherence ◽  
Coherence Analysis ◽  
Nerve Activity ◽  
Phrenic Nerve Activity ◽  
Slow Rhythm ◽  
Nerve Discharge

Phase-locked slow rhythms in sympathetic nerve discharge (SND) and phrenic nerve activity (PNA) are generally thought to arise from a common brain stem "cardiorespiratory" oscillator. The results obtained in vagotomized and baroreceptor-denervated cats anesthetized with pentobarbital sodium do not support this view. First, partial coherence analysis revealed that the discharges of pairs of sympathetic nerves remained correlated at the frequency of the central respiratory cycle after mathematical removal of the portion of these signals common to PNA. The residual coherence suggests that the slow rhythm in SND is dependent on central mechanisms in addition to those responsible for rhythmic PNA. Second, the rhythms in SND and PNA became coupled in a 2:1 relationship during either moderate systemic hypocapnia or hypercapnia. Third, the slow rhythm in SND was maintained when rhythmic PNA was eliminated during extreme hypocapnia. Fourth, during extreme hypercapnia, coherence of the rhythms in SND and PNA was drastically reduced. These results suggest that the slow rhythms in SND and PNA arise from separate oscillators that are normally coupled.

High-cut characteristics of the baroreflex neural arc preserve baroreflex gain against pulsatile pressure

2002 ◽  
Vol 282 (3) ◽  
pp. H1149-H1156 ◽  
Author(s):  
Toru Kawada ◽  
Can Zheng ◽  
Yusuke Yanagiya ◽  
Kazunori Uemura ◽  
Tadayoshi Miyamoto ◽  
...  
Keyword(s):  
Heart Rate ◽  
Transfer Function ◽  
Sympathetic Nerve Activity ◽  
Dynamic Range ◽  
Open Loop ◽  
Loop Gain ◽  
Frequency Range ◽  
Nerve Activity ◽  
Pulsatile Pressure ◽  
Rate Frequency

A transfer function from baroreceptor pressure input to sympathetic nerve activity (SNA) shows derivative characteristics in the frequency range below 0.8 Hz in rabbits. These derivative characteristics contribute to a quick and stable arterial pressure (AP) regulation. However, if the derivative characteristics hold up to heart rate frequency, the pulsatile pressure input will yield a markedly augmented SNA signal. Such a signal would saturate the baroreflex signal transduction, thereby disabling the baroreflex regulation of AP. We hypothesized that the transfer gain at heart rate frequency would be much smaller than that predicted from extrapolating the derivative characteristics. In anesthetized rabbits ( n = 6), we estimated the neural arc transfer function in the frequency range up to 10 Hz. The transfer gain was lost at a rate of −20 dB/decade when the input frequency exceeded 0.8 Hz. A numerical simulation indicated that the high-cut characteristics above 0.8 Hz were effective to attenuate the pulsatile signal and preserve the open-loop gain when the baroreflex dynamic range was finite.

An Experimental Analysis of Interior Noise in an Ambulance and Noise Reduction with Damping Materials

2013 ◽  
Vol 316-317 ◽  
pp. 1118-1122
Author(s):  
Song Bai ◽  
Xin Xi Xu ◽  
Meng Yang ◽  
Xiao Hui Liu ◽  
Wei Hua Su ◽  
...  
Keyword(s):  
Structural Modification ◽  
Coherence Function ◽  
Interior Noise ◽  
Partial Coherence ◽  
Coherence Analysis ◽  
Analysis Method ◽  
Vehicle Interior ◽  
Single Output ◽  
Acoustic Contribution ◽  
Damping Materials

To solve the problem of an ambulance interior noise, a multi-input and single-output linear system model is established based on the partial coherence analysis method. In this model, vibration acceleration signals of panels are treated as input, sound pressure signals is treated as output. The relevant influence among the system inputs are ruled out and the partial coherence function value is considered as an indicator to estimate the panels’ acoustic contribution to the field point. On the basis of analysis, the structural modification with damping materials is performed on the panels with greater contribution. The results show that panels’ acoustic contribution can be analyzed by partial coherence analysis method effectively and structural modification with damping materials based on the method has significant effect on reducing the vehicle interior noise and decreasing additional mass.

Identification of Soil Stabilizer Noise Source with Partial Coherence Analysis

2013 ◽  
Vol 427-429 ◽  
pp. 1785-1788
Author(s):  
Yan Bo Geng ◽  
Lei Lei Gao ◽  
Zhan Wen Zhang ◽  
Zhe Lei Wei
Keyword(s):  
Noise Source ◽  
Coherence Function ◽  
Partial Coherence ◽  
Coherence Analysis ◽  
Noise Sources ◽  
Single Output ◽  
Soil Stabilizer ◽  
Output Noise ◽  
Noise Source Identification ◽  
Identification Model

Since soil stabilizer consists of many operating components, it has lots of noise sources, and the major noise sources are relevant. So, it is appropriate to identify the noise source of the soil stabilizer using the partial coherence analysis. In this paper, a multi-input and single-output noise source identification model is firstly established, and then an algorithm is developed for the calculation of the partial coherence function. Finally, an experiment is carried out with an actual soil stabilizer. In the experiment the main noise sources are accurately identified. This work provides some guidance for further study of vibration and noise reduction of the soil stabilizer.

Partial Spectral Analysis of Cardiac-Related Sympathetic Nerve Discharge

2000 ◽  
Vol 84 (3) ◽  
pp. 1168-1179 ◽  
Author(s):  
Peter D. Larsen ◽  
Craig D. Lewis ◽  
Gerard L. Gebber ◽  
Sheng Zhong
Keyword(s):  
Sympathetic Nerve ◽  
Phase Locking ◽  
Sympathetic Nerves ◽  
Heart Beat ◽  
Partial Coherence ◽  
Coherence Analysis ◽  
Clear Peak ◽  
The Relationship ◽  
Mode Of Coordination ◽  
Nerve Discharge

We have studied the relationship between pulse synchronous baroreceptor input (represented by the arterial pulse, AP) and the cardiac-related rhythm in sympathetic nerve discharge (SND) of urethan-anesthetized cats by using partial autospectral and partial coherence analysis. Partial autospectral analysis was used to mathematically remove the portion of SND that can be directly attributed to the AP, while partial coherence analysis was used to removed the portion of the relationship between the discharges of sympathetic nerve pairs that can be attributed to linear AP-SND relationships that are common to the nerves. The ordinary autospectrum of SND (ASSND) and coherence functions relating the discharges of nerve pairs (CohSND-SND) contained a peak at the frequency of the heart beat. When the predominant mode of coordination between AP and SND was a phase walk, partialization of the autospectra of SND with AP (ASSND/AP) left considerable power in the cardiac-related band. In contrast, when the predominant mode of coordination between AP and SND was phase-locking, there was virtually no cardiac-related activity remaining in ASSND/AP. Partialization of CohSND-SND with AP reduced the peak coherence within the cardiac-related band in both modes of coordination but to a much greater extent during phase-locking. After baroreceptor denervation, CohSND-SND at the cardiac frequency remained significant, although a clear peak above background coherence was no longer apparent. These results are consistent with a model in which the central circuits controlling different sympathetic nerves share baroreceptor inputs and in addition are physically interconnected. The baroreceptor-sympathetic relationship contains both linear and nonlinear components, the former reflected by phase-locking and the latter by phase walk. The residual power in ASSND/AP during phase walk can be attributed to the nonlinear relationship, and the residual peak in partialized nerve-to-nerve coherence (CohSND-SND/AP) arises largely from nonlinearities that are common to the two nerves. During both phase walk and phase-locking, in addition to common nonlinear AP-SND relationships, coupling of the central circuits generating the nerve activities may contribute to CohSND-SND/APbecause significant CohSND-SND was still observed following baroreceptor denervation.

Cardiac- and noncardiac-related coherence between sympathetic drives to muscles of different human limbs

1999 ◽  
Vol 276 (6) ◽  
pp. R1608-R1616 ◽  
Author(s):  
Bernat Kocsis ◽  
Tomas Karlsson ◽  
B. Gunnar Wallin
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Sympathetic Activity ◽  
Partial Coherence ◽  
Coherence Analysis ◽  
Sympathetic Outflow ◽  
Related Factors ◽  
Arterial Blood ◽  
The Common ◽  
Resting Muscle

Partial coherence analysis was used to evaluate the extent to which coherence between resting muscle sympathetic activity (MSA) in different pairs of limbs in humans is explained by the common baroreceptor input and by other noncardiac-related factors. Multiunit MSA in two or three nerves, arterial blood pressure, and electrocardiogram were recorded simultaneously. Correlated MSA consisted of a sharp periodic component at the heart rate and a wideband component of relatively low power distributed between 0 and 2–2.5 Hz. Quantitative analysis revealed stronger coupling between MSAs in close limbs than in distant limbs (peak coherence leg-leg, 0.94 ± 0.03; arm-leg, 0.76 ± 0.11). Furthermore, the wideband component, unaffected by partialization with circulatory signals, was significantly stronger between leg-leg (0.67 ± 0.10) than between arm-leg pairs (0.29 ± 0.10), i.e., noncardiac-related components explained 71% of leg-leg and 38% of arm-leg coherences at the frequency of the heart. Our results indicate that nonuniform relationship exists between resting sympathetic outflow to muscles in close and distant extremities which is, however, partially masked by the effect of the common rhythmic baroreceptor input.

scholarly journals GABA in the paraventricular nucleus tonically suppresses baroreflex function: alterations during pregnancy

2011 ◽  
Vol 300 (6) ◽  
pp. R1452-R1458 ◽  
Author(s):  
Mollie C. Page ◽  
Priscila A. Cassaglia ◽  
Virginia L. Brooks
Keyword(s):  
Heart Rate ◽  
Paraventricular Nucleus ◽  
Sympathetic Nerve ◽  
Sympathetic Nerve Activity ◽  
Sympathetic Nerves ◽  
Gabaergic Inhibition ◽  
Nerve Activity ◽  
Pregnant Rats ◽  
Baroreflex Function

It is well established that GABAergic inputs to the paraventricular nucleus of the hypothalamus (PVN) tonically suppress heart rate and the activity of several sympathetic nerves. However, whether GABA similarly inhibits PVN control of baroreflex function has not been previously investigated. To test this hypothesis, it was determined whether microinjection of the GABAA antagonist, bicuculline, into the PVN enhances the baroreflex in anesthetized female virgin rats. In addition, because GABAergic inhibition of PVN preautonomic neurons is decreased during pregnancy, it was also determined whether the effects of PVN bicuculline administration on baroreflex function were less in pregnant animals. In virgin rats, PVN microinjection of bicuculline increased ( P < 0.05) baroreflex gain and maximum levels of heart rate (gain, from 1.6 ± 0.6 to 3.8 ± 1.3 bpm/mmHg; maximum, from 406 ± 18 to 475 ± 14 bpm) and of lumbar sympathetic nerve activity (gain from 2.6 ± 0.7 to 4.8 ± 1.6%/mmHg; maximum, 149 ± 32 to 273 ± 48%), indicating that PVN GABA normally suppresses baroreflex function. Pregnancy decreased heart rate baroreflex gain (pregnant, 0.9 ± 0.3 bpm/mmHg; virgin, 1.9 ± 0.2 bpm/mmHg; P < 0.05). Following PVN bicuculline administration in pregnant rats, smaller ( P < 0.01) increments in baroreflex gain (pregnant, 0.6 ± 0.1 bpm/mmHg; virgin, 2.4 ± 0.9 bpm/mmHg) and maximum (pregnant, 33 ± 7 bpm; virgin, 75 ± 12 bpm; P < 0.05) were produced. Collectively, these data suggest that the PVN normally inhibits the baroreflex via tonic GABAergic inputs and that this inhibition is less during pregnancy.

Differential relationships among the 10-Hz rhythmic discharges of sympathetic nerves with different targets

1994 ◽  
Vol 267 (2) ◽  
pp. R387-R399 ◽  
Author(s):  
G. L. Gebber ◽  
S. Zhong ◽  
S. M. Barman ◽  
Y. Paitel ◽  
H. S. Orer
Keyword(s):  
Brain Stem ◽  
Cross Talk ◽  
Sympathetic Nerve ◽  
Sympathetic Nerves ◽  
Partial Coherence ◽  
Sharp Peak ◽  
Coherence Analysis

Partial coherence analysis was used to remove the influences of the central circuits controlling a sympathetic nerve (as reflected by its discharges) on the coherence of the 10-Hz discharges of other sympathetic nerves in unanesthetized decerebrate or urethan-anesthetized cats. In many cases, partialization reduced but did not eliminate the sharp peak near 10 Hz in the coherence functions relating the discharges of sympathetic nerve pairs. This observation implies that the central sources of the 10-Hz rhythmic discharges of any nerve are not identical to those responsible for the rhythm recorded from any other nerve. Partial coherence analysis also revealed differential relationships among the 10-Hz rhythmic discharges of sympathetic nerves with different targets. Importantly, the pattern of differential relationships observed in one experiment could be the reverse of that in the next. Although the basis for the differential relationships is not yet clear, nonuniform coupling of multiple brain stem 10-Hz oscillators and/or nonuniform cross talk between spinal circuits controlling different sympathetic nerves may be involved.

The Identification of Relationship between Vibration and Noise of Universal Motor in Working Status

2006 ◽  
Vol 321-323 ◽  
pp. 1616-1619 ◽  
Author(s):  
Min Gi Kim ◽  
Won Woo Hwang ◽  
Soo Hun Lee
Keyword(s):  
System Analysis ◽  
Coherence Function ◽  
Noise Signal ◽  
Partial Coherence ◽  
Coherence Analysis ◽  
Analysis Method ◽  
Washing Machine ◽  
Analysis Methods ◽  
Working Status ◽  
The Relationship

As the home appliances are systemized, they have complicatedly assembled structure. It is reasonable to see the noise problem of home appliance in the viewpoint of system like vehicle and ship. There are various system analysis methods to resolve the noise problem [1-3]. To use system analysis methods, the system information like modal and path properties must be gathered and analyzed. But it takes many times to find out the system properties, so the simpler system analysis methods are needed. The coherence analysis method is useful as the system analysis method, since the method can identify the system property like the relationship between inputs and outputs directly and simply. In the paper, the partial coherence analysis is used for identification of the MISO system of washing machine, in which multi-input signals are vibration signals of motor bracket and an output signal is noise signal of washing machine. The relationship between the noise of washing machine and the vibration of the motor bracket in working status was identified and the parts of bracket closely correlated with noise were also proved by the relationship. And the noise of washing machine was controlled by redesigning the parts of bracket associated with the noise of washing machine based on the coherence function in octave band.

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