Brain stem neuronal types with activity patterns related to sympathetic nerve discharge

1981 ◽  
Vol 240 (5) ◽  
pp. R335-R347 ◽  
Author(s):  
S. M. Barman ◽  
G. L. Gebber
Keyword(s):  
Brain Stem ◽  
Sympathetic Nerve ◽  
Activity Patterns ◽  
Sympathetic Nerves ◽  
Eeg Activity ◽  
Spike Triggered Averaging ◽  
Neuronal Types ◽  
Discharge Patterns ◽  
Electroencephalogram Eeg ◽  
Nerve Discharge

The relationships among the spontaneous activity of single neurons in the cat medulla and inferior cardiac sympathetic nerve discharge (SND), electroencephalogram (EEG) activity, phrenic nerve activity, and the R wave of the electrocardiogram were studied with the methods of spike-triggered averaging and postevent interval analysis. Three categories of neurons (SR, SE, and S) with activity patterns related to SND wee identified. The activity of SR units was related in time to SND and the R wave but not to EEG activity. SE unit discharges were related to SND and EEG activity but not to the R wave. S unit activity was related only to SND. Each of the three categories of neurons could be subdivided into two groups depending on whether their discharges were followed by an increase or a decrease in SND. All unit types exhibited respiratory-related discharge patterns. These data are discussed with regard to the problems associated with the identification of neurons in brain stem networks that govern the discharges of sympathetic nerves.

Hypothalamic neurons with activity patterns related to sympathetic nerve discharge

1982 ◽  
Vol 242 (1) ◽  
pp. R34-R43 ◽  
Author(s):  
S. M. Barman ◽  
G. L. Gebber
Keyword(s):  
Sympathetic Nerve ◽  
Activity Patterns ◽  
Cardiac Sympathetic Nerve ◽  
Hypothalamic Neurons ◽  
Eeg Activity ◽  
Spike Triggered Averaging ◽  
Neuronal Types ◽  
Electroencephalogram Eeg ◽  
Neuronal Type ◽  
Nerve Discharge

Spike-triggered averaging was used to identify hypothalamic neurons with activity patterns related to inferior cardiac sympathetic nerve discharge (SND). Three neuronal types were identified in baroreceptor-innervated cats. The discharges of SR units were temporally related to SND and the R wave of the electrocardiogram. The discharges of SER units were in addition related to electroencephalogram (EEG) activity. SE unit discharges were related to SND and EEG activity but not to the R wave. Two neuronal types were identified in baroreceptor-denervated cats. The discharges of S units were temporally related to SND but not to EEG activity. The second neuronal type exhibited activity patterns similar to those for SE neurons in the baroreceptor-innervated cat. With the exception of SER neurons, all unit types could be subdivided into two groups depending on whether their discharges were followed by an increase or a decrease in SND. The discharges of SER units were followed by a decrease in SND. These data are discussed with regard to the role played by the hypothalamus in generating the basal discharges of sympathetic nerves.xs

Sympathetic-related activity of brain stem neurons in baroreceptor-denervated cats

1981 ◽  
Vol 240 (5) ◽  
pp. R348-R355 ◽  
Author(s):  
G. L. Gebber ◽  
S. M. Barman
Keyword(s):  
Brain Stem ◽  
Sympathetic Nerve ◽  
Activity Patterns ◽  
Cardiac Sympathetic Nerve ◽  
Related Activity ◽  
Eeg Activity ◽  
Cortical Rhythms ◽  
Anatomic Distribution ◽  
Electroencephalogram Eeg ◽  
Nerve Discharge

A search was initiated in baroreceptor-denervated cats for brain stem neurons with activity patterns related to inferior cardiac sympathetic nerve discharge (SND). Neurons whose spontaneous discharges were followed by increases or decreases in SND fell into two categories. S unit discharges were related to SND but not electroencephalogram (EEG) activity. The activity of SE units was related to SND and EEG activity. The anatomic distribution of S and SE units was similar to that previously reported [Barman and Gebber, Am J. Physiol. 240 (Regulatory Integrative Comp. Physiol. 9): R335-R347, 1981] for units with activity patterns related to SND in baroreceptor-innervated cats. Autocorrelograms of S unit discharges and SND contained the same rhythm (2-6 cycles/s). This rhythm was different from that contained in SE unit discharges and EEG activity in experiments in which SND and cortical activity were not related. In other experiments, sympathetic nerve and cortical rhythms were locked to each other. SE units but no S neurons were located in these cats, and the rhythm contained within the autocorrelograms of their discharges was the same as that observed in SND and EEG activity. A model of brain stem networks, which govern the discharges of sympathetic nerve, is presented on the basis of these data.

Coherence of medullary unit activity and sympathetic nerve discharge

1990 ◽  
Vol 259 (3) ◽  
pp. R561-R571 ◽  
Author(s):  
G. L. Gebber ◽  
S. M. Barman ◽  
B. Kocsis
Keyword(s):  
Brain Stem ◽  
Unit Activity ◽  
Sympathetic Nerve ◽  
Sympathetic Nerves ◽  
Frequency Domain Analysis ◽  
Ventrolateral Medulla ◽  
Spike Triggered Averaging ◽  
Time Domains ◽  
The Relationship ◽  
Nerve Discharge

Analyses in the frequency and time domains were used to study the relationships between the discharges of single brain stem neurons and postganglionic sympathetic nerves in baroreceptor-innervated and -denervated cats anesthetized with 5,5-diallylbarbiturate-urethan. Spike-triggered averaging was used initially to identify single neurons with sympathetic nerve-related activity in the medullary lateral tegmental field, rostral ventrolateral medulla, and medullary raphe. The discharges of such neurons were correlated to the 2- to 6-Hz rhythm in sympathetic nerve discharge (SND). Frequency-domain analysis revealed that the relationship between medullary unit activity and the sympathetic nerve rhythm was not fixed from cycle to cycle. First, the coherence values relating the activity of these neurons to SND were closer to zero than to unity in most cases. Second, whereas most of the power in the autospectra of SND was contained between 2 and 6 Hz, that in the autospectra of medullary unit activity was more evenly distributed over a much wider frequency band. These and other observations indicate that the 2- to 6-Hz rhythm is an emergent property of a network of brain stem neurons whose discharges are probabilistically rather than strictly related to the phases of the population rhythm.

Central oscillators responsible for sympathetic nerve discharge

1980 ◽  
Vol 239 (2) ◽  
pp. H143-H155 ◽  
Author(s):  
G. L. Gebber
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Sympathetic Nerve ◽  
Sympathetic Neurons ◽  
Sympathetic Nerves ◽  
Oscillatory Activity ◽  
Periodic Input ◽  
Neuronal Types ◽  
The Central Nervous System ◽  
Nerve Discharge

The current state of knowledge concerning central mechanisms responsible for the generation of background discharges in sympathetic nerves is examined. It is apparent from recent investigations that the classic concept of a randomly discharging and diffusely organized central network onto which rhythms (cardiac- and respiratory-related) are imposed by extrinsic inputs has not passed the test of time. Rather, brain stem as well as spinal networks that govern the discharges of sympathetic nerves are inherently capable of rhythm generation. Sympathetic nerve rhythms inherent to the central nervous system imply the existence of neuronal circuits that are capable of oscillatory activity. Central oscillators provide a mechanism for synchronization of the activity of populations of sympathetic neurons in the absence of periodic input from sources extrinsic to the central nervous system. Indeed, the thesis is developed that, rather than creating rhythms in sympathetic nerve discharge, the function of periodic input from extrinsic sources such as the baroreceptors is to entrain rhythms of central origin. Finally, the problems associated with the identification of neuronal types that comprise central oscillators which govern the discharges of sympathetic nerves are discussed.

Effects of brain stem lesions on 10-Hz and 2- to 6-Hz rhythms in sympathetic nerve discharge

1992 ◽  
Vol 262 (6) ◽  
pp. R1015-R1024 ◽  
Author(s):  
S. Zhong ◽  
S. M. Barman ◽  
G. L. Gebber
Keyword(s):  
Brain Stem ◽  
Sympathetic Nerve ◽  
Sympathetic Nerves ◽  
Ventrolateral Medulla ◽  
Total Power ◽  
Field Potentials ◽  
Brain Stem Lesions ◽  
Stem Lesions ◽  
Nerve Discharge

We studied the effects of brain stem lesions or transection on the 10-Hz and 2- to 6-Hz rhythms in sympathetic nerve discharge (SND) in baroreceptor-denervated unanesthetized decerebrate cats. The results indicate that these two rhythms depend in part on different brain stem regions. The 10-Hz rhythm was eliminated by ablation of the rostral ventrolateral medulla (RVLM), medullary raphe complex, or pontine parabrachial and Kolliker-Fuse complex (PB/KF) or by pontomedullary border transection. Except for RVLM lesions, these procedures did not disrupt the 2- to 6-Hz rhythm in SND. In fact the power in SND at frequencies less than 6 Hz was increased by raphe or PB/KF lesions. Total power in SND was not significantly affected by raphe or PB/KF lesions, but mean arterial pressure was significantly reduced. Field potentials recorded from the RVLM (11 of 26 sites) and raphe (10 of 20 sites) were correlated to the 10-Hz rhythm in SND, further supporting a role of these areas in either generating or relaying this rhythm to sympathetic nerves. In contrast, field potentials recorded from the PB/KF were not correlated to the 10-Hz rhythm in SND. Thus this region may provide a tonic drive to the 10-Hz generator located elsewhere in the brain stem.

Lateral tegmental field neurons play a permissive role in governing the 10-Hz rhythm in sympathetic nerve discharge

1993 ◽  
Vol 265 (5) ◽  
pp. R1006-R1013 ◽  
Author(s):  
S. M. Barman ◽  
G. L. Gebber
Keyword(s):  
Sympathetic Nerve ◽  
Sympathetic Nerves ◽  
Peak Frequency ◽  
Chemical Inactivation ◽  
Rhythm Generator ◽  
Spike Triggered Averaging ◽  
Series Of Experiments ◽  
Decerebrate Cats ◽  
Permissive Role ◽  
Nerve Discharge

Recordings from sympathetic nerves in decerebrate cats show a variable mixture of 10-Hz and 2- to 6-Hz discharges. Although medullary lateral tegmental field (LTF) neurons are considered to be a source of the 2- to 6-Hz oscillation in sympathetic nerve discharge (SND), their role in the control of the 10-Hz rhythm has not been critically evaluated. This issue served as the focus of the current study. In the first series of experiments, spike-triggered averaging of inferior cardiac SND was used in an attempt to identify LTF neurons with activity correlated to the 10-Hz rhythm in SND. The discharges of only one of the 120 LTF neurons studied were correlated to this component of SND. In contrast, 17 of 79 neurons had activity correlated to the 2- to 6-Hz oscillation in experiments in which this component of SND was prominent. These data indicate that LTF neurons neither receive input from nor are components of the 10-Hz rhythm generator. In a second series of experiments, muscimol was microinjected into the LTF bilaterally. Chemical inactivation of the LTF either eliminated the 10-Hz rhythm or reduced the power and peak frequency in this band of SND. These data support the view that LTF neurons have a permissive role in governing the 10-Hz rhythm in SND, probably by acting on elements of the rhythm generator located elsewhere. As expected, muscimol microinjections reduced the power in the 2- to 6-Hz band in SND in some experiments.

Differential control of sympathetic nerve discharge by the brain stem

1984 ◽  
Vol 247 (3) ◽  
pp. R513-R519 ◽  
Author(s):  
S. M. Barman ◽  
G. L. Gebber ◽  
F. R. Calaresu
Keyword(s):  
Brain Stem ◽  
Sympathetic Nerve ◽  
Sympathetic Nerves ◽  
Frequency Component ◽  
External Carotid ◽  
Medullary Raphe ◽  
Reticular Neurons ◽  
Differential Control ◽  
The Brain ◽  
Raphe Neurons

This investigation was designed to test the hypothesis that the brain stem differentially controls the basal discharges of postganglionic sympathetic nerves distributed to different organs. Previous studies have shown that the 2- to 6-Hz activity pattern in sympathetic nerves of the baroreceptor-denervated cat originates in the brain stem. In the current study, autocorrelation and power spectral analyses were used to compare the 2- to 6-Hz frequency components of the simultaneously recorded discharges of postganglionic sympathetic nerve pairs (inferior cardiac and renal; external carotid and renal) in baroreceptor-denervated cats anesthetized with sodium diallylbarbiturate and urethan (Dialurethane). In addition, spike-triggered averaging was used to compare the relative strengths of coupling of the basal discharges of single ventrolateral medullary reticular or medullary raphe neurons to activity in postganglionic sympathetic nerve pairs. The major findings of the study are as follows: 1) the predominant 2- to 6-Hz frequency component in the basal discharges of one sympathetic nerve often was different from that in the discharges of a second nerve, and 2) the activity of approximately one-third of ventrolateral medullary reticular neurons and one-half of medullary raphe neurons (with sympathetic-related activity) was differentially related to the discharges of postganglionic nerve pairs. These results support the view that the brain stem reticular formation and raphe complex exert their influences on different sympathetic nerves in a nonuniform fashion.

Relationships between activity of sympathetic nerve pairs: phase and coherence

1990 ◽  
Vol 259 (3) ◽  
pp. R549-R560 ◽  
Author(s):  
B. Kocsis ◽  
G. L. Gebber ◽  
S. M. Barman ◽  
M. J. Kenney
Keyword(s):  
Frequency Band ◽  
Sympathetic Nerve ◽  
Coherence Function ◽  
Sympathetic Nerves ◽  
Phase Spectrum ◽  
Central System ◽  
Functional States ◽  
Alpha Chloralose ◽  
Constant Interval ◽  
Nerve Discharge

The coherence function and phase spectrum were used to study the relationships between the discharges of sets of two postganglionic or preganglionic sympathetic nerves in baroreceptor-denervated cats anesthetized with either 5,5-diallylbarbiturate-urethan or alpha-chloralose. Most of the power in sympathetic nerve discharge was contained between 2 and 6 Hz. The coherence values relating the activity of two nerves were significantly different from zero within this frequency band. The phase spectrum was either linear or complex (i.e., showed changes in slope) within the coherent frequency band. We observed three patterns of relationship. The first pattern was characterized by a constant interval between activity in different sympathetic nerves within the coherent frequency band. The second pattern was characterized by a frequency-dependent interval. The third pattern was characterized by uncoupling of the 2- to 6-Hz rhythms in the discharges of different nerves. Switching between these patterns was observed. We suggest that the three patterns reflect different functional states of the central system responsible for the 2- to 6-Hz rhythm. Two models of this system are entertained. The first model is one of a system of coupled oscillators while filtering circuits that receive common inputs are the elements of the second model.

Role of the brain stem in generating the 2- to 6-Hz oscillation in sympathetic nerve discharge

1993 ◽  
Vol 265 (5) ◽  
pp. R1026-R1035 ◽  
Author(s):  
S. Zhong ◽  
Z. S. Huang ◽  
G. L. Gebber ◽  
S. M. Barman
Keyword(s):  
Brain Stem ◽  
Sympathetic Nerve ◽  
Cervical Spinal Cord ◽  
Ventrolateral Medulla ◽  
Population Activity ◽  
A Value ◽  
Decerebrate Cats ◽  
The Brain ◽  
Nerve Discharge

We tested the hypothesis that brain stem circuits normally generate a 2- to 6-Hz oscillation in sympathetic nerve discharge (SND). Experiments were performed on baroreceptor-denervated decerebrate cats and urethan-anesthetized rats in which renal or splanchnic SND was recorded along with field potentials (population activity) from sites in the rostral ventrolateral medulla, medullary raphe, or medullary lateral tegmental field. Our major findings were as follows. 1) Population activity recorded from the three medullary regions contained a 2- to 6-Hz oscillation. 2) The 2- to 6-Hz oscillation in population activity recorded from some medullary sites was correlated to that in SND. Peak coherence in the 2- to 6-Hz band approached a value of 1 in some cases. 3) Whereas cervical spinal cord transection abolished or markedly reduced SND, the 2- to 6-Hz oscillation in medullary activity was essentially unchanged. These results support the view that the 2- to 6-Hz oscillation in SND can be generated in the brain stem of cats and rats.

scholarly journals Aging alters regulation of visceral sympathetic nerve responses to acute hypothermia

2006 ◽  
Vol 291 (3) ◽  
pp. R573-R579 ◽  
Author(s):  
Bryan G. Helwig ◽  
Sujatha Parimi ◽  
Chanran K. Ganta ◽  
Richard Cober ◽  
Richard J. Fels ◽  
...  
Keyword(s):  
Sympathetic Nerve ◽  
Sympathetic Nerves ◽  
Middle Aged ◽  
Fischer 344 ◽  
Skin Cooling ◽  
Young Subjects ◽  
Colonic Temperature ◽  
Induced Changes ◽  
F344 Rats ◽  
Nerve Discharge

Hypothermia produced by acute cooling prominently alters sympathetic nerve outflow. Skin sympathoexcitatory responses to skin cooling are attenuated in aged compared with young subjects, suggesting that advancing age influences sympathetic nerve responsiveness to hypothermia. However, regulation of skin sympathetic nerve discharge (SND) is only one component of the complex sympathetic nerve response profile to hypothermia. Whether aging alters the responsiveness of sympathetic nerves innervating other targets during acute cooling is not known. In the present study, using multifiber recordings of splenic, renal, and adrenal sympathetic nerve activity, we tested the hypothesis that hypothermia-induced changes in visceral SND would be attenuated in middle-aged and aged compared with young Fischer 344 (F344) rats. Colonic temperature (Tc) was progressively reduced from 38°C to 31°C in young (3 to 6 mo), middle-aged (12 mo), and aged (24 mo) baroreceptor-innervated and sinoaortic-denervated (SAD), urethane-chloralose anesthetized, F344 rats. The following observations were made. 1) Progressive hypothermia significantly ( P < 0.05) reduced splenic, renal, and adrenal SND in young baroreceptor-innervated F344 rats. 2) Reductions in splenic, renal, and adrenal SND to progressive hypothermia were less consistently observed and, when observed, were generally attenuated in baroreceptor-innervated middle-aged and aged compared with young F344 rats. 3) Differences in splenic, renal, and adrenal SND responses to reduced Tc were observed in SAD young, middle-aged, and aged F344 rats, suggesting that age-associated attenuations in SND responses to acute cooling are not the result of age-dependent modifications in arterial baroreflex regulation of SND. These findings demonstrate that advancing chronological age alters the regulation of visceral SND responses to progressive hypothermia, modifications that may contribute to the inability of aged individuals to adequately respond to acute bouts of hypothermia.

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