Completed

NCT Number: NCT06518356

Mastoid taVNS-fMRI

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.

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Key information

Conditions

Auricular Stimulation

Age range

18 year–65 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Medical University of South Carolina Institute of Psychiatry

Charleston, South Carolina, 29425, United States

About this study

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.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Age 18-65
Have the capacity and ability to provide one's own consent in English and sign the informed consent document.

Exclusion criteria

Unable to speak in English.
Contraindicated for MRI.
Any current or recent untreated medical, neurological, or psychiatric conditions
Metal implant devices in the head, heart or neck.
History of brain surgery.
History of myocardial infarction or arrhythmia, bradycardia.
Personal or family history of seizure or epilepsy or personal use of medications that substantially reduce seizure threshold (e.g., olanzapine, chlorpromazine, lithium).
Personal history of head injury, concussion, or self-report of moderate to severe traumatic brain injury.
Participant has abnormal ear anatomy, skin irritation, or ear infection present
Individuals suffering from frequent/severe headaches.
Individuals with a reported history of psychosis or mania, or individuals who are actively manic or psychotic.
Moderate to severe alcohol or substance use disorder.
Pregnancy

Treatment and study plan

Transcutaneous Auricular Neurostimulation (tAN)

Device

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).

Primary outcomes

Blood oxygen level-dependent (BOLD) signal changes during stimulation relative to sham stimulation

Time frame: 30 minutes

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.

Sponsors and collaborators

Lead sponsor

Medical University of South Carolina

Other

Registry information

Official study title

Investigating the Direct Brain Effects of Activating the Auricular Branch of the Vagus Nerve From the Cymba Concha or Mastoid Process: a Sham-controlled fMRI Study

Important dates

Study start: 2024
Primary completion: 2025
Study completion: 2025
First posted: Jul 24, 2024
Registry last updated: Jul 4, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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