scholarly journals Event-related transcutaneous vagus nerve stimulation modulates behaviour and pupillary responses during an auditory oddball task

2021 ◽  
Author(s):  
Ruben Azevedo ◽  
Gianluca Finotti ◽  
Daniele Di Lernia ◽  
Valerio Villani ◽  
Manos Tsakiris
Keyword(s):  
Vagus Nerve ◽  
Cognitive Processes ◽  
Nerve Stimulation ◽  
Vagus Nerve Stimulation ◽  
Temporal Dynamics ◽  
Pupil Dilation ◽  
Oddball Paradigm ◽  
Auditory Oddball ◽  
Transcutaneous Vagus Nerve Stimulation ◽  
Pupillary Responses

Transcutaneous auricular vagus nerve stimulation (taVNS) is a neuromodulatory technique that is thought to activate the Locus Coeruleus-Noradrenaline (LC-NA) system. Standard taVNS protocols consist of the administration of intermittent or continuous stimulation over long periods. However, there is currently limited understanding of temporal dynamics of taVNS modulation of cognitive processes, as well as its mechanisms of action. We argue that novel stimulation approaches, informed by established theories of the LC-NA system, are needed to further our understanding of the neurocognitive underpinnings of taVNS. In this pre-registered study, we tested whether an “event-related” taVNS protocol can modulate the LC-NA system. In a within-subject design (single session) we delivered brief trains of taVNS (3 seconds) during an auditory oddball paradigm. The taVNS was time-locked to the target stimuli and randomly interleaved with sham stimulation. Response times (RT) and stimuli-driven pupillary diameter (PD) were used as indices of LC-NA activity. Results revealed that active taVNS increased RT to targets, as compared to sham trials. Notably, in line with current theories of LC-NA functioning, taVNS modulation of target-related pupil dilation depended on pre-stimulation PD, an index of tonic LC-NA activity. In particular, active (vs. sham) taVNS was associated with smaller pupil dilation in trials where the baseline PD was small. These results demonstrate, for the first time, the effectiveness of brief event-related taVNS in the modulation of cognitive processes and highlight the importance of using pupil size as an index of tonic and phasic LC-NA activity.

scholarly journals Transcutaneous vagus nerve stimulation in humans induces pupil dilation and attenuates alpha oscillations

2020 ◽  
Author(s):  
Omer Sharon ◽  
Firas Fahoum ◽  
Yuval Nir
Keyword(s):  
Electrical Stimulation ◽  
Vagus Nerve ◽  
Nerve Stimulation ◽  
Vagus Nerve Stimulation ◽  
Pupil Dilation ◽  
Somatosensory Stimulation ◽  
Alpha Oscillations ◽  
Sham Stimulation ◽  
Non Invasive ◽  
Transcutaneous Vagus Nerve Stimulation

AbstractVagus nerve stimulation (VNS) is widely used to treat drug-resistant epilepsy and depression. While the precise mechanisms mediating its long-term therapeutic effects are not fully resolved, they likely involve locus coeruleus (LC) stimulation via the nucleus of the solitary tract (NTS), which receives afferent vagal inputs. In rats, VNS elevates LC firing and forebrain noradrenaline levels, whereas LC lesions suppress VNS therapeutic efficacy. Non-invasive transcutaneous VNS (tVNS) employs electrical stimulation that targets the auricular branch of the vagus nerve at the cymba conchae of the ear. However, the extent that tVNS mimics VNS remains unclear. Here, we investigated the short-term effects of tVNS in healthy human male volunteers (n=24), using high-density EEG and pupillometry during visual fixation at rest. We compared short (3.4s) trials of tVNS to sham electrical stimulation at the earlobe (far from the vagus nerve branch) to control for somatosensory stimulation. Although tVNS and sham stimulation did not differ in subjective intensity ratings, tVNS led to robust pupil dilation (peaking 4-5s after trial onset) that was significantly higher than following sham stimulation. We further quantified, using parallel factor analysis, how tVNS modulates idle occipital alpha (8-13Hz) activity identified in each participant. We found greater attenuation of alpha oscillations by tVNS than by sham stimulation. This demonstrates that tVNS reliably induces pupillary and EEG markers of arousal beyond the effects of somatosensory stimulation, thus supporting the hypothesis that tVNS elevates noradrenaline and other arousal-promoting neuromodulatory signaling, and mimics invasive VNS.Significance statementCurrent non-invasive brain stimulation techniques are mostly confined to modulating cortical activity, as is typical with transcranial magnetic or transcranial direct/alternating-current electrical stimulation. Transcutaneous vagus nerve stimulation (tVNS) has been proposed to stimulate subcortical arousal-promoting nuclei, though previous studies yielded inconsistent results. Here we show that short (3.4s) tVNS pulses in naïve healthy male volunteers induced transient pupil dilation and attenuation of occipital alpha oscillations. These markers of brain arousal are in line with the established effects of invasive VNS on locus coeruleus-noradrenaline signaling, and support the notion that tVNS mimics VNS. Therefore, tVNS can be used as a tool for studying the means by which endogenous subcortical neuromodulatory signaling affects human cognition, including perception, attention, memory, and decision-making; and also for developing novel clinical applications.

Effect of Transcutaneous Vagus Nerve Stimulation in Dysphagia After Lateral Medullary Infarction: A Case Report

2019 ◽  
Vol 28 (4) ◽  
pp. 1381-1387
Author(s):  
Ying Yuan ◽  
Jie Wang ◽  
Dongyu Wu ◽  
Dahua Zhang ◽  
Weiqun Song
Keyword(s):  
Vagus Nerve ◽  
Nerve Stimulation ◽  
Vagus Nerve Stimulation ◽  
Rating Scale ◽  
Tube Feeding ◽  
Nasogastric Feeding ◽  
Lateral Medullary Infarction ◽  
Severe Dysphagia ◽  
Transcutaneous Vagus Nerve Stimulation ◽  
Medullary Infarction

Purpose Severe dysphagia with weak pharyngeal peristalsis after dorsal lateral medullary infarction (LMI) requires long-term tube feeding. However, no study is currently available on therapeutic effectiveness in severe dysphagia caused by nuclear damage of vagus nerve after dorsal LMI. The purpose of the present investigation was to explore the potential of transcutaneous vagus nerve stimulation (tVNS) to improve severe dysphagia with weak pharyngeal peristalsis after dorsal LMI. Method We assessed the efficacy of 6-week tVNS in a 28-year-old woman presented with persisting severe dysphagia after dorsal LMI who had been on nasogastric feeding for 6 months. tVNS was applied for 20 min twice a day, 5 days a week, for 6 weeks. The outcome measures included saliva spitted, Swallow Function Scoring System, Functional Oral Intake Scale, Clinical Assessment of Dysphagia With Wallenberg Syndrome, Yale Pharyngeal Residue Severity Rating Scale, and upper esophagus X-ray examination. Results After tVNS, the patient was advanced to a full oral diet without head rotation or spitting. No saliva residue was found in the valleculae and pyriform sinuses. Contrast medium freely passed through the upper esophageal sphincter. Conclusion Our findings suggest that tVNS might provide a useful means for recovery of severe dysphagia with weak pharyngeal peristalsis after dorsal LMI. Supplemental Material https://doi.org/10.23641/asha.9755438

scholarly journals Transcutaneous Vagus Nerve Stimulation is Associated with Lower Mechanical Ventilation and Mortality in COVID-19 Patients

2021 ◽  
Vol 6 (2) ◽  
Author(s):  
Nemechek P ◽  
Antonelli G ◽  
Braida A
Keyword(s):  
Mechanical Ventilation ◽  
Respiratory Failure ◽  
Vagus Nerve ◽  
Nerve Stimulation ◽  
Vagus Nerve Stimulation ◽  
Safety And Efficacy ◽  
Transcutaneous Vagus Nerve Stimulation

Objective: Evaluate the safety and efficacy of transcutaneous vagus nerve stimulation in preventing respiratory failure and improving survival in hospitalized COVID-19 patients.

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