Optimization of Transcutaneous Vagus Nerve Stimulation Using Functional MRI.
Citations
180 citations
Cites background or methods from "Optimization of Transcutaneous Vagu..."
...The earlobe has been widely used as a sham as it is thought to be relatively free of vagal afferents (Peuker & Filler, 2002; Yakunina et al. 2017) and innervated by the greater auricular nerve – a branch of the superficial cervical plexus....
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...On the other hand, the same study showed that stimulation at the inner wall of the tragus and cymba concha successfully activated the vagal afferent pathway, with the greatest activation seen at the cymba concha, suggesting that this is the most promising site for auricular tVNS (Yakunina et al. 2017)....
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...2018b) and cymba concha (Frangos et al. 2015; Yakunina et al. 2017; Wang et al. 2018) as active sites for vagal modulation, as supported by the cadaveric study conducted by Peuker & Filler (2002)....
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...In one tVNS study, several regions of the limbic system were deactivated by both sham stimulation (applied at the earlobe) and tVNS (applied at the inner surface of the tragus, inferoposterior wall of the external acoustic meatus and cymba concha): namely, the hippocampus, the posterior cingulate gyrus, parahippocampal gyrus and amygdala (Yakunina et al. 2017)....
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...Secondly, researchers should appreciate that stimulation of the earlobe is not physiologically inert and can produce very similar fMRI patterns to ABVN stimulation, although there is no substantial published evidence to date that the locus coeruleus and nucleus of the solitary tract (central vagal relay centres) are activated by electrical stimulation of the earlobe (Frangos et al. 2015; Yakunina et al. 2017)....
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170 citations
157 citations
Cites background from "Optimization of Transcutaneous Vagu..."
...Only the cymba concha was found so far to be solely innervated by aVN (Peuker and Filler, 2002) with the associated maximum activation of vagal projections in NTS during stimulation, as compared to tragus, cavum concha, or earlobe stimulation (Yakunina et al., 2016)....
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...However, current imaging studies in humans are usually focused on VNactivated brain stem nuclei and their projections (Yakunina et al., 2016)....
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..., 2007), whereas a significantly stronger activation of the NTS was proven when the cymba concha region was electrically stimulated in humans compared to sham stimulation and other auricular regions (Yakunina et al., 2016)....
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...Auricular vagus nerve stimulation is typically performed at the tragus or (cavum, cymba) concha (Yakunina et al., 2016)....
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128 citations
118 citations
References
578 citations
"Optimization of Transcutaneous Vagu..." refers background in this paper
...Recently, a rat model was used to demonstrate that VNS paired with tones reverses tinnitus-related plasticity of the auditory cortex (11)....
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568 citations
503 citations
"Optimization of Transcutaneous Vagu..." refers background in this paper
...The earlobe is primarily innervated by the great auricular nerve that originates from the cervical nerve (C2); thus, CES does not stimulate the ABVN (21)....
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...On the other hand, the cymba conchae was innervated by the ABVN in 100% of cases, which makes it a more attractive candidate and may have contributed to the fact that the cymba conchae performed better than the inner tragus in terms of stimulating the ABVN in the present study....
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...To minimize these negative aspects, transcutaneous stimulation of the afferent auricular branch of the vagus nerve (ABVN) at the external ear has been considered as an alternative treatment option (15)....
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...Three locations were selected for stimulation based on existing knowledge regarding the anatomical distribution of the ABVN (21–24), previous tVNS fMRI studies (16–19), and the stimulation locations for commercially available tVNS devices: the inner surface of the tragus, the inferoposterior wall of the external acoustic meatus (ear canal), and the cymba conchae....
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...Although the cough reflex (Arnold’s reflex), which is induced by the mechanical stimulation of the ABVN, is consistently evoked by touching the inferoposterior wall of the ear canal, the ABVN location inside of the ear canal appears quite variable among subjects (21–23)....
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499 citations
"Optimization of Transcutaneous Vagu..." refers background in this paper
...The NTS projects to numerous areas in forebrain, limbic, and brainstem structures (17,19,20) including the LC, which is the major noradrenergic nucleus in the brain and plays a key role in the mechanisms of action underlying VNS (27,28,37,38)....
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434 citations
"Optimization of Transcutaneous Vagu..." refers background or methods in this paper
...Only two of these studies reported activity in the NTS, which is the primary brain region receiving projections from the vagus nerve (17,19,20)....
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...The NTS projects to numerous areas in forebrain, limbic, and brainstem structures (17,19,20) including the LC, which is the major noradrenergic nucleus in the brain and plays a key role in the mechanisms of action underlying VNS (27,28,37,38)....
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...Only two studies have previously succeeded in demonstrating this type of activation (17,19), whereas another study reported only ipsilateral LC activation (18)....
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...Four previous studies have investigated the effects of tVNS using fMRI, but several different areas of the ear were stimulated; namely, the inner wall of the tragus (16–18), the posterior side of the ear canal (17), and the cymba conchae (19)....
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...First, the control location for the sham stimulation (earlobe) was chosen for the present study because a majority of previous tVNS studies (16,17,19) also used this location due to its proximity to other studied vagus-innervated locations and because it is known to be anatomically free of vagal innervation....
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