scholarly journals The role of the paravertebral ganglia in human sympathetic neural discharge patterns

2018 ◽  
Vol 596 (18) ◽  
pp. 4497-4510 ◽  
Author(s):  
Stephen A. Klassen ◽  
Jacqueline K. Limberg ◽  
Sarah E. Baker ◽  
Wayne T. Nicholson ◽  
Timothy B. Curry ◽  
...  
2018 ◽  
Vol 32 (S1) ◽  
Author(s):  
Stephen A. Klassen ◽  
Jacqueline K. Limberg ◽  
Sarah E. Baker ◽  
Wayne T. Nicholson ◽  
Timothy B. Curry ◽  
...  

2020 ◽  
Vol 129 (2) ◽  
pp. 230-237
Author(s):  
Tyler D. Vermeulen ◽  
Brooke M. Shafer ◽  
Anthony V. Incognito ◽  
Massimo Nardone ◽  
André L. Teixeira ◽  
...  

We characterize the occurrence of a square-wave discharge pattern of efferent muscle sympathetic nerve activity during a sinus pause in a young healthy male. This discharge pattern comprised large recruited action potential clusters undetected at baseline that continuously discharged during the sinus pause. Notably, this discharge pattern was still contained within a single cardiac cycle.


2020 ◽  
Vol 318 (5) ◽  
pp. R961-R971 ◽  
Author(s):  
Elizabeth P. Ott ◽  
Dain W. Jacob ◽  
Sarah E. Baker ◽  
Walter W. Holbein ◽  
Zachariah M. Scruggs ◽  
...  

We examined the effect of acute intermittent hypoxia (IH) on sympathetic neural firing patterns and the role of the carotid chemoreceptors. We hypothesized exposure to acute IH would increase muscle sympathetic nerve activity (MSNA) via an increase in action potential (AP) discharge rates and within-burst firing. We further hypothesized any change in discharge patterns would be attenuated during acute chemoreceptor deactivation (hyperoxia). MSNA (microneurography) was assessed in 17 healthy adults (11 male/6 female; 31 ± 1 yr) during normoxic rest before and after 30 min of experimental IH. Prior to and following IH, participants were exposed to 2 min of 100% oxygen (hyperoxia). AP patterns were studied from the filtered raw MSNA signal using wavelet-based methodology. Compared with baseline, multiunit MSNA burst incidence ( P < 0.01), AP incidence ( P = 0.01), and AP content per burst ( P = 0.01) were increased following IH. There was an increase in the probability of a particular AP cluster firing once ( P < 0.01) and more than once ( P = 0.03) per burst following IH. There was no effect of hyperoxia on multiunit MSNA at baseline or following IH ( P > 0.05); however, hyperoxia following IH attenuated the probability of particular AP clusters firing more than once per burst ( P < 0.01). Acute IH increases MSNA by increasing AP discharge rates and within-burst firing. A portion of the increase in within-burst firing following IH can be attributed to the carotid chemoreceptors. These data advance the mechanistic understanding of sympathetic activation following acute IH in humans.


2016 ◽  
Vol 311 (6) ◽  
pp. R1013-R1021 ◽  
Author(s):  
Mark B. Badrov ◽  
T. Dylan Olver ◽  
J. Kevin Shoemaker

Sympathetic outflow is modified during acute homeostatic stress through increased firing of low-threshold axons, recruitment of latent axons, and synaptic delay modifications. However, the role of central mechanisms versus peripheral reflex control over sympathetic recruitment remains unknown. Here, we examined sympathetic discharge patterns during fatiguing static handgrip (SHG) exercise and postexercise circulatory occlusion (PECO) to study the central vs. peripheral reflex elements of sympathetic neural coding. Muscle sympathetic nerve activity (MSNA; microneurography) was measured in six males (25 ± 3 yr) at baseline (3 min) and during 5 min of SHG exercise completed at 20% maximal voluntary contraction. Isolation of the peripheral metaboreflex component was achieved by PECO for 3 min. Action potential (AP) patterns were studied using wavelet-based methodology. Compared with baseline, total MSNA increased by minute 3 of SHG, remaining elevated throughout the duration of exercise and PECO (all P < 0.05). The AP content per burst increased above baseline by minute 4 of SHG (Δ4 ± 2), remaining elevated at minute 5 (Δ6 ± 4) and PECO (Δ4 ± 4; all P < 0.05). Similarly, total AP clusters increased by minute 4 of SHG (Δ5 ± 5) and remained elevated at minute 5 (Δ6 ± 3) and PECO (Δ7 ± 5; all P < 0.01), indicating recruitment of latent subpopulations. Finally, the AP cluster size-latency profile was shifted downward during minutes 4 (−32 ± 22 ms) and 5 (−49 ± 17 ms; both P < 0.05) of SHG but was not different than baseline during PECO ( P > 0.05). Our findings suggest that central perceptual factors play a specific role in the synaptic delay aspect of sympathetic discharge timing, whereas peripheral reflex mechanisms affect recruitment of latent axons.


2006 ◽  
Vol 96 (5) ◽  
pp. 2465-2478 ◽  
Author(s):  
Jisue Lee ◽  
Chun-Fang Wu

A seizure-paralysis repertoire characteristic of Drosophila “bang-sensitive” mutants can be evoked electroconvulsively in tethered flies, in which behavioral episodes are associated with synchronized spike discharges in different body parts. Flight muscle DLMs (dorsal longitudinal muscles) display a stereotypic sequence of initial and delayed bouts of discharges (ID and DD), interposed with giant fiber (GF) pathway failure and followed by a refractory period. We examined how seizure susceptibility and discharge patterns are modified in various K+ and Na+ channel mutants. Decreased numbers of Na+ channels in nap ts flies drastically reduced susceptibility to seizure induction, eliminated ID, and depressed DD spike generation. Mutations of different K+ channels led to differential modifications of the various components in the repertoire. Altered transient K+ currents in Sh 133 and Hk mutants promoted ID induction. However, only Sh 133 but not Hk mutations increased DD seizure and GF pathway failure durations. Surprisingly, modifications in sustained K+ currents in eag and Shab mutants increased thresholds for DD induction and GF pathway failure. Nevertheless, both eag and Shab, like Sh 133, increased DD spike generation and recovery time from GF pathway failure. Interactions between channel mutations with the bang-sensitive mutation bss demonstrated the role of membrane excitability in stress-induced seizure-paralysis behavior. Seizure induction and discharges were suppressed by nap ts in bss nap double mutants, whereas Sh heightened seizure susceptibility in bss Sh 133 and bss Sh M double mutants. Our results suggest that individual seizure repertoire components reflect different neural network activities that could be differentially altered by mutations of specific ion channel subunits.


1996 ◽  
Vol 76 (1) ◽  
pp. 353-370 ◽  
Author(s):  
C. A. Scudder ◽  
A. K. Moschovakis ◽  
A. B. Karabelas ◽  
S. M. Highstein

1. The discharge patterns and axonal projections of saccadic long-lead burst neurons (LLBNs) with somata in the pontine reticular formation were studied in alert squirrel monkeys with the use of the method of intraaxonal recording and horseradish peroxidase injection. 2. The largest population of stained neurons were afferents to the cerebellum. They originated in the dorsomedial nucleus reticularis tegmenti pontis (NRTP) including its dorsal cell group (N = 5), the preabducens intrafascicular nucleus (N = 5), and the raphe pontis (N = 1). Axons of all neurons coursed under NRTP and entered brachium pontis without having synapsed in the brain stem. Three axons sent collaterals to the floccular lobe, but other more distant targets of these and the other cerebellar afferents could not be determined. Movement fields of these neurons were intermediate between vectorial and directional types. 3. Four neurons had their somata in nucleus reticularis pontis oralis and terminations in the brain stem reticular formation. Each neuron was different, but all terminated in the region containing excitatory burst neurons, and most terminated in the region containing inhibitory burst neurons. Other targets include nucleus reticularis pontis oralis and caudalis, NRTP, raphe interpositus, and the spinal cord. Discharge patterns included both vectorial and directional types. 4. Two reticulospinal neurons had large multipolar somata either just rostral or ventral to the abducens nucleus. These neurons also projected to the medullary reticular formation, caudal nucleus prepositus hypoglossi, and dorsal and ventral paramedian reticular nucleus. 5. The functional implications of the connections of these LLBNs and those reported in the companion paper are extensively discussed. The fact that the efferents of the superior colliculus target the regions containing medium-lead saccadic burst neurons confirms the role of the colliculus in saccade generation. However, the finding that many other neurons project to these regions and the finding that superior colliculus efferents project more heavily to areas containing reticulospinal neurons argue for a diminished role of the superior colliculus in saccade generation but an augmented role in head movement control.


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