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The influence of respiration on brainstem and cardiovagal response to auricular vagus nerve stimulation: A multimodal ultrahigh-field (7T) fMRI study
- Source :
- Brain Stimul, Brain Stimulation, Vol 12, Iss 4, Pp 911-921 (2019)
- Publication Year :
- 2018
-
Abstract
- Background Brainstem-focused mechanisms supporting transcutaneous auricular VNS (taVNS) effects are not well understood, particularly in humans. We employed ultrahigh field (7T) fMRI and evaluated the influence of respiratory phase for optimal targeting, applying our respiratory-gated auricular vagal afferent nerve stimulation (RAVANS) technique. Hypothesis We proposed that targeting of nucleus tractus solitarii (NTS) and cardiovagal modulation in response to taVNS stimuli would be enhanced when stimulation is delivered during a more receptive state, i.e. exhalation. Methods Brainstem fMRI response to auricular taVNS (cymba conchae) was assessed for stimulation delivered during exhalation (eRAVANS) or inhalation (iRAVANS), while exhalation-gated stimulation over the greater auricular nerve (GANctrl, i.e. earlobe) was included as control. Furthermore, we evaluated cardiovagal response to stimulation by calculating instantaneous HF-HRV from cardiac data recorded during fMRI. Results Our findings demonstrated that eRAVANS evoked fMRI signal increase in ipsilateral pontomedullary junction in a cluster including purported NTS. Brainstem response to GANctrl localized a partially-overlapping cluster, more ventrolateral, consistent with spinal trigeminal nucleus. A region-of-interest analysis also found eRAVANS activation in monoaminergic source nuclei including locus coeruleus (LC, noradrenergic) and both dorsal and median raphe (serotonergic) nuclei. Response to eRAVANS was significantly greater than iRAVANS for all nuclei, and greater than GANctrl in LC and raphe nuclei. Furthermore, eRAVANS, but not iRAVANS, enhanced cardiovagal modulation, confirming enhanced eRAVANS response on both central and peripheral neurophysiological levels. Conclusion 7T fMRI localized brainstem response to taVNS, linked such response with autonomic outflow, and demonstrated that taVNS applied during exhalation enhanced NTS targeting.
- Subjects :
- Adult
Male
Vagus Nerve Stimulation
medicine.medical_treatment
Biophysics
Stimulation
Serotonergic
050105 experimental psychology
Article
lcsh:RC321-571
03 medical and health sciences
Electrocardiography
Young Adult
0302 clinical medicine
Heart Rate
Monoaminergic
medicine
otorhinolaryngologic diseases
Animals
Humans
0501 psychology and cognitive sciences
Neuroscience (all)
Neurology (clinical)
lcsh:Neurosciences. Biological psychiatry. Neuropsychiatry
business.industry
General Neuroscience
05 social sciences
Spinal trigeminal nucleus
Settore FIS/07
Vagus Nerve
Magnetic Resonance Imaging
medicine.anatomical_structure
Respiratory Mechanics
Transcutaneous Electric Nerve Stimulation
Locus coeruleus
Female
Brainstem
Raphe nuclei
business
Neuroscience
030217 neurology & neurosurgery
Vagus nerve stimulation
Brain Stem
Subjects
Details
- ISSN :
- 18764754
- Volume :
- 12
- Issue :
- 4
- Database :
- OpenAIRE
- Journal :
- Brain stimulation
- Accession number :
- edsair.doi.dedup.....f85291a21fb3b6755af6afd8014a7c68