Transcutaneous auricular vagus nerve stimulation can modulate fronto-parietal brain networks

Author: Sang-Yoon Han1, Leeseul Shim2,3, Hyo-Jeong Lee#2,3,4, Moo Kyun Park#5,6
Affiliation: <sup>1</sup> Department of Otolaryngology-Head and Neck Surgery, College of Medicine, Hanyang University, Seoul, Republic of Korea. <sup>2</sup> Laboratory of Brain and Cognitive Sciences for Convergence Medicine, Hallym University College of Medicine, Anyang-si, Republic of Korea. <sup>3</sup> Ear and Interaction Center, Doheun Institute for Digital Innovation in Medicine, Hallym University Medical Center, Anyang-si, Republic of Korea. <sup>4</sup> Department of Otorhinolaryngology-Head and Neck Surgery, Hallym University College of Medicine, Chuncheon-si, Republic of Korea. <sup>5</sup> Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Hospital, Seoul, Republic of Korea. <sup>6</sup> Sensory Organ Research Institute, Seoul National University, Medical Research Center, Seoul, Republic of Korea.
Conference/Journal: Front Neurosci
Date published: 2024 Jul 18
Other: Volume ID: 18 , Pages: 1368754 , Special Notes: doi: 10.3389/fnins.2024.1368754. , Word Count: 260


Objective:
Recent studies have shown that transcutaneous vagal nerve stimulation (tVNS) holds promise as a treatment for neurological or psychiatric disease through the ability to modulate neural activity in some brain regions without an invasive procedure. The objective of this study was to identify the neural correlates underlying the effects of tVNS.

Methods:
Twenty right-handed healthy subjects with normal hearing participated in this study. An auricle-applied tVNS device (Soricle, Neurive Co., Ltd., Gyeongsangnam-do, Republic of Korea) was used to administer tVNS stimulation. A session consisted of 14 blocks, including 7 blocks of tVNS stimulation or sham stimulation and 7 blocks of rest, and lasted approximately 7 min (1 block = 30 s). Functional magnetic resonance imaging (fMRI) was performed during the stimulation.

Results:
No activated regions were observed in the fMRI scans following both sham stimulation and tVNS after the first session. After the second session, tVNS activated two clusters of brain regions in the right frontal gyrus. A comparison of the activated regions after the second session of each stimulation revealed that the fMRI following tVNS exhibited four surviving clusters. Additionally, four clusters were activated in the overall stimulated area during both the first and second sessions. When comparing the fMRI results after each type of stimulation, the fMRI following tVNS showed four surviving clusters compared to the fMRI after sham stimulation.

Conclusion:
tVNS could stimulate some brain regions, including the fronto-parietal network. Stimulating these regions for treating neurological or psychiatric disease might require applying tVNS for at least 3.5 min.

Keywords: brain mapping; fronto-parietal network; neuromodulation; neurostimulation; transcutaneous vagal nerve stimulation.

PMID: 39091347 PMCID: PMC11292796 DOI: 10.3389/fnins.2024.1368754