The purpose of this study is to explore whether stimulating different outer parts of the ear using a non-invasive form of ear stimulation called transcutaneous auricular vagus nerve stimulation (taVNS) will create different brain activation images. Investigators will recruit 24 healthy participants. The ear stimulation will be delivered while taking brain images using a magnetic resonance imaging (MRI) machine.
Transcutaneous auricular vagus nerve stimulation (taVNS) is a non-invasive neuromodulation technique that delivers electric stimulation to the auricular branch of the vagus nerve (ABVN). This technique has been demonstrated effective in the treatment of depression and addiction in previous studies. Most previous applications of taVNS targeted the ABVN via the cymba conchae or tragus sites. The mastoid process (mastoid site) is an important dermatome innervated by the ABVN, but there is currently a lack of knowledge on how taVNS on the mastoid site affects brain activity and whether it differs from the effect of stimulating the cymba site. In this proposed study, the investigators plan to explore whether delivering taVNS to the mastoid site and the cymba site can induce different patterns of brain activity. Ultimately, if successful, this project will not only deepen our knowledge in basic neuroscience but also have great value in clinical applications since the mastoid site is a much more accessible ABVN target compared to other sites.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
24
The intervention the investigators are studying is called transcutaneous auricular neurostimulation (tAN). tAN is simply electrical nerve stimulation administered at the ear which targets the auricular branch of the vagus nerve (ABVN) at the cymba conchae and mastoid process, and to a sham site (earlobe).
Medical University of South Carolina Institute of Psychiatry
Charleston, South Carolina, United States
Blood oxygen level-dependent (BOLD) signal changes during stimulation relative to sham stimulation
taVNS will be administered to participants within the bore of the MRI scanner while the investigators acquire high-resolution functional neuroimaging. Both a general linear model and SNM approach will be used to examine BOLD signal changes during stimulation relative to rest blocks, comparing each of the 3 stimulation targets within- and between- subjects to identify any differences in brain activity during stimulation of the mastoid site compared to the cymba site and sham site.
Time frame: 30 minutes
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