Men Show Reduced Cardiac Baroreceptor Sensitivity during Modestly Painful Electrical Stimulation of the Forearm: Exploratory Results from a Sham-Controlled Crossover Vagus Nerve Stimulation Study

International Journal of Environmental Research and Public Health, Journal Year: 2021, Volume and Issue: 18(21), P. 11193 - 11193

Published: Oct. 25, 2021

This paper presents data from a transcutaneous vagus nerve stimulation experiment that point towards blunted cardiac baroreceptor sensitivity (cBRS) in young males compared to females during electrical of the forearm and rhythmic breathing task. Continuous electrocardiography, impedance cardiography continuous blood-pressure recordings were assessed sex-matched cohort twenty healthy subjects. Electrical median was conducted by using threshold-tracking method combined with two tasks (0.1 0.2 Hz) before, after active or sham stimulation. Autonomic hemodynamic parameters calculated, differences analyzed linear mixed models post hoc F-tests. None autonomic differed between conditions. However, females, male participants had an overall lower total cBRS independent condition (females: 14.96 ± 5.67 ms/mmHg, males: 11.89 3.24 p = 0.031) at Hz 21.49 8.47 15.12 5.70 0.004). Whereas left inner tragus did not affect efferent vagal control heart, we found similar patterns activation over period both sexes, which, however, significantly their magnitude, showing higher cBRS.

Language: Английский

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Tonic and phasic transcutaneous auricular vagus nerve stimulation both evoke rapid and transient pupil dilation

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2023, Volume and Issue: unknown

Published: Sept. 22, 2023

Abstract Background Transcutaneous auricular vagus nerve stimulation (tVNS or taVNS) is a non-invasive method of electrical the afferent pathway nerve, suggested to drive changes in putative physiological markers noradrenergic activity, including pupil dilation. Objective However, it unknown whether different taVNS modes can map onto phasic and tonic activity. The effects on dilation humans are inconsistent, largely due differences protocols. Here, we attempted address these issues. Methods We investigated under (1 s) (30 taVNS, pre-registered, single-blind, sham-controlled, within-subject cross-over design, absence behavioural task. Results Phasic induced rapid increase size over baseline, significantly greater than sham stimulation, which rapidly declined after offset. Tonic similarly (and larger sham) returning baseline within 5 s, despite ongoing stimulation. Thus, both active closely resembled effect. There were no size, sustained size. Conclusions These results suggest that phasic- tonic-like standard parameters may modulate primarily mode as indexed by evoked dilation, above somatosensory effects. This result sheds light temporal profile with implications for their applicability further research.

Language: Английский

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Can transcutaneous auricular vagus nerve stimulation mitigate vigilance loss? Examining the effects of stimulation at individualized vs. constant current intensity

Authorea (Authorea), Journal Year: 2024, Volume and Issue: unknown

Published: May 27, 2024

According to the arousal model of vigilance, locus coeruleus-norepinephrine (LC-NE) system modulates sustained attention over long periods by regulating physiological arousal. Recent research has proposed that transcutaneous auricular vagus nerve stimulation (taVNS) indirect markers LC-NE activity, although its effects on vigilance have not yet been examined. Aiming develop a safe and non-invasive procedure prevent failures in prolonged tasks, present study examined possibility mitigate loss stimulating via taVNS. Following pre-registered protocol (https://osf.io/tu2xy/), 50 participants completed three repeated-sessions randomized order which either active taVNS at individualized intensity set participant, 0.5 mA for all participants, or sham taVNS, was delivered while performing an attentional task (i.e., ANTI-Vea). Changes salivary alpha-amylase cortisol concentrations were measured as activity. Self-reports feelings associated with guessing rate active/sham conditions supported efficacy single-blind procedure. Contrary our predictions, observed decrement modulated Pairwise comparisons showed mitigation reduction across time. Interestingly, Spearman’s correlational analyses some inter-individual LC-NE, evidenced positive associations between changes but We highlight relevance replicating extending outcomes, investigating further parameters other

Language: Английский

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The effects of transcutaneous auricular vagus nerve stimulation (taVNS) on cholinergic neural networks in humans: A neurophysiological study

Clinical Neurophysiology, Journal Year: 2024, Volume and Issue: 169, P. 47 - 52

Published: Nov. 27, 2024

Language: Английский

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The effects of fasting and dehydration on pupillary light reflex as detected by pupillometry

Clinical Physiology and Functional Imaging, Journal Year: 2024, Volume and Issue: 45(1)

Published: Dec. 23, 2024

Abstract The pupillary light reflex could serve as a valuable method for measuring dynamic responses in the autonomic nervous system (ANS). However, it remains unclear whether physiological conditions such fasting and dehydration affect reflexes. In this study, we investigated effects of on using pupillometry. Measurements were taken after at least 12 h Ramadan (RF) under normal dietary pattern (NDP). Forty‐nine volunteers, who had no complaints related to ANS, participated study. initial pupil diameter (IPD), amplitude contraction, contraction velocity, latency, dilatation duration, dilation velocity recorded. IPD was 5.91 ± 0.65 mm RF condition 5.72 NDP ( p < 0.001). Both (CA) (DV) higher = 0.010 0.022, respectively). Females exhibited greater 0.023). Differences between genders observed CA 0.002), duration 0.016) latency 0.041). These findings indicate that influence IPD, DV. Therefore, is informative consider status when evaluating pupillometry results.

Language: Английский

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