Convergence of afferents from the SLN and GPN in cat medullary swallowing neurons

Ootani, Shinji; Umezaki, Toshiro; Shin, Takemoto; Murata, Yuzo

doi:10.1016/0361-9230(95)00018-6

Cited by 71 publications

(52 citation statements)

References 21 publications

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“…The greater facilitatory effect of bilateral stimulation, relative to unilateral stimulation, may reflect the importance of spatial summation of oropharyngeal afferent inputs in swallowing elicitation. This possibility is consistent with the evidence that swallow-related neurons in the medulla can be influenced by spatial summation [44][45][46][47][48]. A related possibility is that sensory inputs from both sides of the oropharynx preferentially evoke swallowing.…”

Section: Bilateral Vs Unilateral Oropharyngeal Stimulationsupporting

confidence: 79%

Effects of Oropharyngeal Air-Pulse Stimulation on Swallowing in Healthy Older Adults

et al. 2009

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While previous research has shown that air-pulse stimulation of the oropharynx facilitates saliva swallowing in young adults, the effects of air pulses in older adults have not been examined. Responses to air-pulse stimulation may differ in young and older adults given age-related changes in sensation, swallowing physiology, and swallow-related brain activation. Therefore, this study sought to determine the effects of oropharyngeal air-pulse stimulation on saliva swallowing rates in 18 healthy older adults. Saliva swallowing rates were monitored across six conditions: baseline without mouthpiece, baseline with mouthpiece in situ, unilateral right oropharyngeal stimulation, unilateral left oropharyngeal stimulation, bilateral oropharyngeal stimulation, and sham stimulation. Results indicated that bilateral oropharyngeal air-pulse stimulation was associated with a statistically significant increase in mean saliva swallowing rate compared to baseline without mouthpiece, baseline with mouthpiece in situ, and sham stimulation. In previous studies, young adults reported an irrepressible urge to swallow in response to oropharyngeal air-pulse delivery, but the older adults in the current study did not perceive the air-pulse stimulation as being associated with swallowing or other behaviors. These findings indicate that oropharyngeal air-pulse stimulation facilitates the elicitation of saliva swallowing in older adults.

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Section: Bilateral Vs Unilateral Oropharyngeal Stimulationsupporting

confidence: 79%

Effects of Oropharyngeal Air-Pulse Stimulation on Swallowing in Healthy Older Adults

et al. 2009

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“…The NTS neurons receive many laryngeal sensory inputs via the superior laryngeal nerve in the intermediate and interstitial subnuclei, and via the recurrent laryngeal nerve in the medial subnucleus of the NTS (Kalia and Sullivan 1982;Altschuler et al 1989;Mrini and Jean 1995;Ootani et al 1995;Brining and Smith 1996;Aicher et al 1999). The neurons in the intermediate and interstitial subnuclei of the NTS receive excitatory inputs by the terminals containing glutamate from the nodose ganglion (Sykes et al 1997), and send fibers to the CT motoneurons (Barrett et al 1994).…”

Section: Discussionmentioning

confidence: 98%

Monosynaptic inputs from the nucleus tractus solitarii to the laryngeal motoneurons in the nucleus ambiguus of the rat

Hayakawa

Takanaga

Maeda

et al. 2000

Anatomy and Embryology

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The cricothyroid (CT) and the posterior cricoarytenoid (PCA) muscles in the larynx are activated by the laryngeal motoneurons located within the nucleus ambiguus; these motoneurons receive the laryngeal sensory information from the nucleus tractus solitarii (NTS) during respiration and swallowing. We investigated whether the neurons in the NTS projected directly to the laryngeal motoneurons, and what is the synaptic organization of their nerve terminals on the laryngeal motoneurons using the electron microscope. When wheat germ agglutinin-conjugated horseradish peroxidase (WGA-HRP) was injected into the NTS after cholera toxin subunit B-conjugated HRP (CT-HRP) was injected into the CT muscle or the PCA muscle, the anterogradely WGA-HRP-labeled terminals from the NTS were found to directly contact the retrogradely CT-HRP-labeled dendrites and soma of both the CT and the PCA motoneurons. The labeled NTS terminals comprised about 4% of the axosomatic terminals in a section through the CT motoneurons, and about 9% on both the small (PCA-A) and the large (PCA-B) PCA motoneurons. The number of labeled axosomatic terminals containing round vesicles and making asymmetric synaptic contacts (Gray's type I) was almost equal to that of the labeled terminals containing pleomorphic vesicles and making symmetric synaptic contacts (Gray's type II) on the CT motoneurons. The labeled axosomatic terminals were mostly Gray's type II on the PCA-A motoneurons, while the majority of them were Gray's type I on the PCA-B motoneurons. These results indicate that the laryngeal CT and PCA motoneurons receive a few direct excitatory and inhibitory inputs from the neurons in the NTS.

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“…Indeed, stimulation of multiple, whole nerve trunks in vivo supports the presence of multiple afferents converging on some individual NTS neurons (Donoghue et al 1985;Mifflin 1996). On close examination, however, such studies commonly suggest that multiafferent convergence is relatively rare, ranging from as high as 10 to 15% of NTS neurons, for example in cat NTS (43/292 neurons) (Donoghue et al 1985), in rabbit (7/45) (Bonham and Hasser 1993) or in other cat studies (3/28 neurons) (Ootani et al 1995) down to as low as 1-2% in some cat studies (1/56 neurons) (Mifflin 1996). More commonly, the cross-nerve convergent inputs (e.g., carotid sinus and superior laryngeal nerves) met polysynaptic criteria in cells that received a monosynaptic input from one of the nerves (Mifflin 1996): a finding quite consistent with our results.…”

Section: Visceral Afferent Convergence-slice Responses Resemble Intacmentioning

confidence: 99%

Organization and Properties of GABAergic Neurons in Solitary Tract Nucleus (NTS)

Bailey

Appleyard

Jin

et al. 2008

Journal of Neurophysiology

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. Cranial visceral afferents enter the brain at the solitary tract nucleus (NTS). GABAergic neurons are scattered throughout the NTS, but their relation to solitary tract (ST) afferent pathways is imprecisely known. We hypothesized that most GABAergic NTS neurons would be connected only indirectly to the ST. We identified GABAergic neurons in brain stem horizontal slices using transgenic mice in which enhanced green fluorescent protein (EGFP) expression was linked to glutamic acid decarboxylase expression (GAD ϩ ). Finely graded electrical shocks to ST recruit STsynchronized synaptic events with all-or-none thresholds and individual waveforms did not change with greater suprathreshold intensities-evidence consistent with initiation by single afferent axons. Most (ϳ70%) GAD ϩ neurons received ST-evoked excitatory postsynaptic currents (EPSCs) that had minimally variant latencies (jitter, SD of latency Ͻ200 s) and waveforms consistent with single, direct ST connections (i.e., monosynaptic). Increasing stimulus intensity evoked additional ST-synchronized synaptic responses with jitters Ͼ200 s including inhibitory postsynaptic currents (IPSCs), indicating indirect connections (polysynaptic). Shocks of suprathreshold intensity delivered adjacent (50 -300 m) to the ST failed to excite non-ST inputs to second-order neurons, suggesting a paucity of axons passing near to ST that connected to these neurons. Despite expectations, we found similar ST synaptic patterns in GAD ϩ and unlabeled neurons. Generally, ST information that arrived indirectly had small amplitudes (EPSCs and IPSCs) and frequency-dependent failures that reached Ͼ50% for IPSCs to bursts of stimuli. This ST afferent pathway organization is strongly use-dependent-a property that may tune signal propagation within and beyond NTS.

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Convergence of afferents from the SLN and GPN in cat medullary swallowing neurons

Cited by 71 publications

References 21 publications

Effects of Oropharyngeal Air-Pulse Stimulation on Swallowing in Healthy Older Adults

Effects of Oropharyngeal Air-Pulse Stimulation on Swallowing in Healthy Older Adults

Monosynaptic inputs from the nucleus tractus solitarii to the laryngeal motoneurons in the nucleus ambiguus of the rat

Organization and Properties of GABAergic Neurons in Solitary Tract Nucleus (NTS)

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