Localization of Adductor and Abductor Motor Nerve Fibers to the Larynx

1977 ◽  
Vol 86 (6) ◽  
pp. 770-776 ◽  
Author(s):  
Richard R. Gacek ◽  
Leslie T. Malmgren ◽  
Michael J. Lyon
Keyword(s):  
Vagus Nerve ◽  
Motor Neurons ◽  
Motor Nerve ◽  
Functional Results ◽  
Nerve Fibers ◽  
Nucleus Ambiguus ◽  
Axoplasmic Flow ◽  
Anterograde Degeneration ◽  
Almost All ◽  
The Brain

Knowledge of the location of motor nerve fibers to the adductor and abductor muscles of the larynx may be useful in the diagnosis and treatment of innervation disorders in this organ. Anterograde degeneration and retrograde tracer anatomical techniques have demonstrated the central and peripheral positions of these two groups of motor nerve fibers in the cat. Traditional nerve fiber degeneration methods applied following intracranial transection of the vagus nerve rootlets indicated that: 1) Most of the fibers in the recurrent laryngeal nerve (RLN) are motor; 2) Almost all of these motor fibers leave the brain stem in the most rostral rootlet(s) of the vagus nerve; and 3) Motor fibers to the larynx form a discrete bundle within the trunk of the vagus nerve before forming the RLN. A tracer (horseradish peroxidase) of retrograde axoplasmic flow in motor neurons has been employed to demonstrate: 1) Dorsoventral division of the adductor and abductor neurons in the nucleus ambiguus; and 2) Diffuse arrangement of both adductor and abductor nerve fibers in the vagus nerve but collection of these fibers into abductor and adductor halves of the RLN prior to entering the larynx. These findings dispel theories of differential cord paralysis (Semon's law) based on a vulnerable position of abductor fibers at the periphery of the RLN. Furthermore, the diffuse arrangement of these fiber groups explains the usually mixed functional results obtained following reimplantation of the RLN into a laryngeal muscle.

scholarly journals In vivo visualization of pig vagus nerve ‘vagotopy’ using ultrasound

2020 ◽  
Author(s):  
Megan L. Settell ◽  
Maisha Kasole ◽  
Aaron C. Skubal ◽  
Bruce E. Knudsen ◽  
Evan N. Nicolai ◽  
...  
Keyword(s):  
Vagus Nerve ◽  
Motor Nerve ◽  
Nerve Fibers ◽  
Patient Specific ◽  
Neck Muscle ◽  
Therapeutic Effects ◽  
Ultrasound Images ◽  
Anatomical Landmarks ◽  
Novel Approach

AbstractBackgroundPlacement of the clinical vagus nerve stimulating cuff is a standard surgical procedure based on anatomical landmarks, with limited patient specificity in terms of fascicular organization or vagal anatomy. As such, the therapeutic effects are generally limited by unwanted side effects of neck muscle contractions, demonstrated by previous studies to result from stimulation of 1) motor fibers near the cuff in the superior laryngeal and 2) motor fibers within the cuff projecting to the recurrent laryngeal.ObjectiveThe use of patient-specific visualization of vagus nerve fascicular organization could better inform clinical cuff placement and improve clinical outcomes.MethodsThe viability of ultrasound, with the transducer in the surgical pocket, to visualize vagus nerve fascicular organization (i.e. vagotopy) was characterized in a pig model. Ultrasound images were matched to post-mortem histology to confirm the utility of ultrasound in identifying fascicular organization.ResultsHigh-resolution ultrasound accurately depicted the vagotopy of the pig vagus nerve intra-operatively, as confirmed via histology. The stereotypical pseudo-unipolar cell body aggregation at the nodose ganglion was identifiable, and these sensory afferent fascicular bundles were traced down the length of the vagus nerve. Additionally, the superior and recurrent laryngeal nerves were identified via ultrasound.ConclusionsIntraoperative visualization of vagotopy and surrounding nerves using ultrasound is a novel approach to optimize stimulating cuff placement, avoid unwanted activation of motor nerve fibers implicated in off-target effects, and seed patient-specific models of vagal fiber activation to improve patient outcomes.

Differential control over postganglionic neurons in rat cardiac ganglia by NA and DmnX neurons: anatomical evidence

2004 ◽  
Vol 286 (4) ◽  
pp. R625-R633 ◽  
Author(s):  
Zixi (Jack) Cheng ◽  
Hong Zhang ◽  
Shang Z. Guo ◽  
Robert Wurster ◽  
David Gozal
Keyword(s):  
Brain Stem ◽  
Motor Neurons ◽  
Nucleus Ambiguus ◽  
Motor Nucleus ◽  
Sprague Dawley ◽  
Tracer Injection ◽  
Cardiac Ganglia ◽  
Dorsal Motor Nucleus ◽  
Differential Control ◽  
The Brain

In previous single-labeling experiments, we showed that neurons in the nucleus ambiguus (NA) and the dorsal motor nucleus of the vagus (DmnX) project to intrinsic cardiac ganglia. Neurons in these two motor nuclei differ significantly in the size of their projection fields, axon caliber, and endings in cardiac ganglia. These differences in NA and DmnX axon cardiac projections raise the question as to whether they target the same, distinct, or overlapping populations of cardiac principal neurons. To address this issue, we examined vagal terminals in cardiac ganglia and tracer injection sites in the brain stem using two different anterograde tracers {1,1′-dioleyl-3,3,3′,3′-tetramethylindocarbocyanine methanesulfonate and 4-[4-(dihexadecylamino)-styryl]- N-methylpyridinium iodide} and confocal microscopy in male Sprague-Dawley rats. We found that 1) NA and DmnX neurons innervate the same cardiac ganglia, but these axons target separate subpopulations of principal neurons and 2) axons arising from neurons in the NA and DmnX in the contralateral sides of the brain stem enter the cardiac ganglionic plexus through separate bundles and preferentially innervate principal neurons near their entry regions, providing topographic mapping of vagal motor neurons in left and right brain stem vagal nuclei. Because the NA and DmnX project to distinct populations of cardiac principal neurons, we propose that they may play different roles in controlling cardiac function.

scholarly journals Identification of a brainstem locus that inhibits tumor necrosis factor

2020 ◽  
Vol 117 (47) ◽  
pp. 29803-29810 ◽  
Author(s):  
Adam M. Kressel ◽  
Tea Tsaava ◽  
Yaakov A. Levine ◽  
Eric H. Chang ◽  
Meghan E. Addorisio ◽  
...  
Keyword(s):  
Tumor Necrosis Factor ◽  
Vagus Nerve ◽  
Tumor Necrosis ◽  
Cholinergic Neurons ◽  
Nerve Fibers ◽  
Motor Nucleus ◽  
Dorsal Motor Nucleus ◽  
Pharmacological Blockade ◽  
The Brain ◽  
Necrosis Factor

In the brain, compact clusters of neuron cell bodies, termed nuclei, are essential for maintaining parameters of host physiology within a narrow range optimal for health. Neurons residing in the brainstem dorsal motor nucleus (DMN) project in the vagus nerve to communicate with the lungs, liver, gastrointestinal tract, and other organs. Vagus nerve-mediated reflexes also control immune system responses to infection and injury by inhibiting the production of tumor necrosis factor (TNF) and other cytokines in the spleen, although the function of DMN neurons in regulating TNF release is not known. Here, optogenetics and functional mapping reveal cholinergic neurons in the DMN, which project to the celiac-superior mesenteric ganglia, significantly increase splenic nerve activity and inhibit TNF production. Efferent vagus nerve fibers terminating in the celiac-superior mesenteric ganglia form varicose-like structures surrounding individual nerve cell bodies innervating the spleen. Selective optogenetic activation of DMN cholinergic neurons or electrical activation of the cervical vagus nerve evokes action potentials in the splenic nerve. Pharmacological blockade and surgical transection of the vagus nerve inhibit vagus nerve-evoked splenic nerve responses. These results indicate that cholinergic neurons residing in the brainstem DMN control TNF production, revealing a role for brainstem coordination of immunity.

scholarly journals Genetic identification of a hindbrain nucleus essential for innate vocalization

2017 ◽  
Vol 114 (30) ◽  
pp. 8095-8100 ◽  
Author(s):  
Luis Rodrigo Hernandez-Miranda ◽  
Pierre-Louis Ruffault ◽  
Julien C. Bouvier ◽  
Andrew J. Murray ◽  
Marie-Pierre Morin-Surun ◽  
...  
Keyword(s):  
Motor Neurons ◽  
Nucleus Tractus Solitarius ◽  
Nucleus Ambiguus ◽  
Genetic Identification ◽  
Innate Response ◽  
Newborn Mice ◽  
Brain Center ◽  
Expiratory Muscles ◽  
Biomechanical Parameters ◽  
The Brain

Vocalization in young mice is an innate response to isolation or mechanical stimulation. Neuronal circuits that control vocalization and breathing overlap and rely on motor neurons that innervate laryngeal and expiratory muscles, but the brain center that coordinates these motor neurons has not been identified. Here, we show that the hindbrain nucleus tractus solitarius (NTS) is essential for vocalization in mice. By generating genetically modified newborn mice that specifically lack excitatory NTS neurons, we show that they are both mute and unable to produce the expiratory drive required for vocalization. Furthermore, the muteness of these newborns results in maternal neglect. We also show that neurons of the NTS directly connect to and entrain the activity of spinal (L1) and nucleus ambiguus motor pools located at positions where expiratory and laryngeal motor neurons reside. These motor neurons control expiratory pressure and laryngeal tension, respectively, thereby establishing the essential biomechanical parameters used for vocalization. In summary, our work demonstrates that the NTS is an obligatory component of the neuronal circuitry that transforms breaths into calls.

scholarly journals Voltage-Gated Sodium Channels Mediating Conduction in Vagal Motor Fibers Innervating the Esophageal Striated Muscle

2021 ◽  
pp. S471-S478
Author(s):  
N PAVELKOVA ◽  
M BROZMANOVA ◽  
M JAYANTA PATIL ◽  
M KOLLARIK
Keyword(s):  
Action Potential ◽  
Vagus Nerve ◽  
Sodium Channels ◽  
Striated Muscle ◽  
Nerve Fibers ◽  
Nucleus Ambiguus ◽  
Motor Nucleus ◽  
Efferent Nerve ◽  
Voltage Gated ◽  
Voltage Gated Sodium Channels

The vagal motor fibers innervating the esophageal striated muscle are essential for esophageal motility including swallowing and vomiting. However, it is unknown which subtypes of voltage-gated sodium channels (NaV1s) regulate action potential conduction in these efferent nerve fibers. The information on the NaV1s subtypes is necessary for understanding their potential side effects on upper gut, as novel inhibitors of NaV1s are developed for treatment of pain. We used isolated superfused (35 °C) vagally-innervated mouse esophagus striated muscle preparation (mucosa removed) to measure isometric contractions of circular striated muscle evoked by electrical stimulation of the vagus nerve. NaV1 inhibitors were applied to the de-sheathed segment of the vagus nerve. Tetrodotoxin (TTX) applied to the vagus nerve completely abolished electrically evoked contractions. The selective NaV1.7 inhibitor PF-05089771 alone partially inhibited contractions and caused a >3-fold rightward shift in the TTX concentration-inhibition curve. The NaV1.1, NaV1.2 and NaV1.3 group inhibitor ICA-121431 failed to inhibit contractions, or to alter TTX concentration-inhibition curves in the absence or in the presence of PF-05089771. RT-PCR indicated lack of NaV1.4 expression in nucleus ambiguus and dorsal motor nucleus of the vagus nerve, which contain motor and preganglionic neurons projecting to the esophagus. We conclude that the action potential conduction in the vagal motor fibers to the esophageal striated muscle in the mouse is mediated by TTX-sensitive voltage gated sodium channels including NaV1.7 and most probably NaV1.6. The role of NaV1.6 is supported by ruling out other TTX-sensitive NaV1s (NaV1.1-1.4) in the NaV1.7-independent conduction.

scholarly journals Intrinsic positional memory guides target-specific axon regeneration in the zebrafish vagus nerve

Development ◽  
2021 ◽  
Vol 148 (18) ◽  
Author(s):  
Adam J. Isabella ◽  
Jason A. Stonick ◽  
Julien Dubrulle ◽  
Cecilia B. Moens
Keyword(s):  
Vagus Nerve ◽  
Motor Nerve ◽  
Target Selection ◽  
Branch Points ◽  
Developmental Guidance ◽  
Peripheral Nerve Damage ◽  
Injury Model ◽  
Mechanistic Basis ◽  
The Brain ◽  
Correct Target

ABSTRACT Regeneration after peripheral nerve damage requires that axons re-grow to the correct target tissues in a process called target-specific regeneration. Although much is known about the mechanisms that promote axon re-growth, re-growing axons often fail to reach the correct targets, resulting in impaired nerve function. We know very little about how axons achieve target-specific regeneration, particularly in branched nerves that require distinct targeting decisions at branch points. The zebrafish vagus motor nerve is a branched nerve with a well-defined topographic organization. Here, we track regeneration of individual vagus axons after whole-nerve laser severing and find a robust capacity for target-specific, functional re-growth. We then develop a new single-cell chimera injury model for precise manipulation of axon-environment interactions and find that (1) the guidance mechanism used during regeneration is distinct from the nerve's developmental guidance mechanism, (2) target selection is specified by neurons' intrinsic memory of their position within the brain, and (3) targeting to a branch requires its pre-existing innervation. This work establishes the zebrafish vagus nerve as a tractable regeneration model and reveals the mechanistic basis of target-specific regeneration.

Fiber Components of the Recurrent Laryngeal Nerve in the Cat

1976 ◽  
Vol 85 (4) ◽  
pp. 460-471 ◽  
Author(s):  
Richard R. Gacek ◽  
Michael J. Lyon
Keyword(s):  
Recurrent Laryngeal Nerve ◽  
Motor Nerve ◽  
Cranial Nerves ◽  
Superior Laryngeal Nerve ◽  
Muscle Spindles ◽  
Nerve Fibers ◽  
Laryngeal Nerve ◽  
Nucleus Ambiguus ◽  
Fiber Components ◽  
Sensory Fibers

Experimental neuroanatomical methods were employed in 21 adult cats to determine 1) the number and size of myelinated motor and sensory fibers in the recurrent laryngeal nerve (RLN), and 2) the fiber components originating in the nucleus ambiguus (NA) and retrofacial nucleus (RFN) of the brain stem. Intracranial transection of the X and XI cranial nerves and selective destruction of the NA or RFN were the experimental lesions inflicted in order to obtain the following results. About 55% (312) of the right RLN (565 fibers) is composed of myelinated motor nerve fibers which measure 4 μ − 9 μ in diameter. Nine percent come from the RFN and are smaller (4–6 μ) than the 46% which emanate from the NA and measure 6–9 μ in diameter. The remaining 45% of the RLN is made up of sensory neurons which can be divided into three groups. 1)The largest numerical group (32%) is very small in caliber (1–3 μ) and supplies extralaryngeal regions (trachea, esophagus). 2) The intermediate size fiber group (4–9 μ) comprises 11% of the RLN and probably supplies the subglottic mucosa. 3) The smallest group (2%) of sensory fibers is the largest in diameter (10–15 μ) and may represent either the innervation of muscle spindles or afferents from the superior laryngeal nerve coursing down into the chest.

scholarly journals Sources of Off-Target Effects of Vagus Nerve Stimulation Using the Helical Clinical Lead in Domestic Pigs

2020 ◽  
Author(s):  
Evan N. Nicolai ◽  
Megan L. Settell ◽  
Bruce E. Knudsen ◽  
Andrea L. McConico ◽  
Brian A. Gosink ◽  
...  
Keyword(s):  
Side Effects ◽  
Vagus Nerve ◽  
Nerve Stimulation ◽  
Vagus Nerve Stimulation ◽  
Muscle Activation ◽  
Motor Nerve ◽  
Nerve Fibers ◽  
Large Animal ◽  
C Fibers ◽  
Target Effects

AbstractClinical data suggest that efficacious vagus nerve stimulation (VNS) is limited by side effects such as cough and dyspnea that have stimulation thresholds lower than those for therapeutic outcomes. VNS side effects are putatively caused by activation of nearby muscles within the neck, via direct muscle activation or activation of nerve fibers innervating those muscles. Our goal was to determine the thresholds at which various VNS-evoked effects occur in the domestic pig—an animal model with vagus anatomy similar to human—using the bipolar helical lead deployed clinically. Intrafascicular electrodes were placed within the vagus nerve to record electroneurographic (ENG) responses, and needle electrodes were placed in the vagal-innervated neck muscles to record electromyographic (EMG) responses. Contraction of the cricoarytenoid muscle occurred at low amplitudes (∼0.3 mA) and resulted from activation of motor nerve fibers in the cervical vagus trunk within the electrode cuff which bifurcate into the recurrent laryngeal branch of the vagus. At higher amplitudes (∼1.4 mA), contraction of the cricoarytenoid and cricothyroid muscles was generated by current leakage outside the cuff to activate motor nerve fibers running within the nearby superior laryngeal branch of the vagus. Activation of these muscles generated artifacts in the ENG recordings that may be mistaken for compound action potentials representing slowly conducting Aδ-, B-, and C-fibers. Our data resolve conflicting reports of the stimulation amplitudes required for C-fiber activation in large animal studies (>10 mA) and human studies (<250 µA). After removing muscle-generated artifacts, ENG signals with post-stimulus latencies consistent with Aδ- and B-fibers occurred in only a small subset of animals, and these signals had similar thresholds to those that caused bradycardia. By identifying specific neuroanatomical pathways that cause off-target effects and characterizing the stimulation dose-response curves for on- and off-target effects, we hope to guide interpretation and optimization of clinical VNS.

Quantity and Three-Dimensional Position of the Recurrent and Superior Laryngeal Nerve Lower Motor Neurons in a Rat Model

2011 ◽  
Vol 120 (11) ◽  
pp. 761-768 ◽  
Author(s):  
Philip Weissbrod ◽  
Michael J. Pitman ◽  
Sansar Sharma ◽  
Aaron Bender ◽  
Steven D. Schaefer
Keyword(s):  
Motor Neurons ◽  
Rat Model ◽  
Three Dimensional ◽  
Superior Laryngeal Nerve ◽  
Laryngeal Nerve ◽  
Nucleus Ambiguus ◽  
Sprague Dawley ◽  
3 Dimensional ◽  
Sprague Dawley Rats ◽  
The Brain

Objectives: We sought to elucidate the 3-dimensional position and quantify the lower motor neurons (LMNs) of the recurrent laryngeal nerve (RLN) and the superior laryngeal nerve (SLN) in a rat model. Quantification and mapping of these neurons will enhance the usefulness of the rat model in the study of reinnervation following trauma to these nerves. Methods: Female Sprague-Dawley rats underwent microsurgical transection of the RLN, the SLN, or both the RLN and SLN or sham surgery. After transection, either Fluoro-Ruby (FR) or Fluoro-Gold (FG) was applied to the proximal nerve stumps. The brain stems were harvested, sectioned, and examined for fluorolabeling. The LMNs were quantified, and their 3-dimensional position within the nucleus ambiguus was mapped. Results: Labeling of the RLN was consistent regardless of the labeling agent used. A mean of 243 LMNs was documented for the RLN. The SLN labeling with FR was consistent and showed a mean of 117 LMNs; however, FG proved to be highly variable in labeling the SLN. The SLN LMNs lie rostral and ventral to those of the RLN. In the sham surgical condition, FG was noted to contaminate adjacent tissues — In particular, in the region of the SLN. Conclusions: Fluorolabeling is an effective tool to locate and quantify the LMNs of the RLN and SLN. The LMN positions and counts were consistent when FR was used in labeling of either the RLN or the SLN. Fluoro-Gold, however, because of its tendency to contaminate surrounding structures, can only be used to label the RLN. Also, as previously reported, the SLN LMNs lie rostral and ventral to those of the RLN. This information results in further clarification of a rat model of RLN injury that may be used to investigate the effects of neurotrophic factors on RLN reinnervation.

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