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Investigating the Transcutaneous vs. Transcranial Mechanisms of Trigeminal Nerve Stimulation (eTNS) Using fMRI

NCT07657260 · Status: RECRUITING · Phase: NA · Type: INTERVENTIONAL · Enrollment: 25

Last updated 2026-06-18

No results posted yet for this study

Summary

Transcutaneous Trigeminal Nerve Stimulation (eTNS) is a non-invasive technique that modulates brain activity by applying electrical currents to the forehead. However, it remains unclear whether its effects are primarily driven by activating peripheral nerves in the skin (the transcutaneous pathway) or by the electrical current passing directly through the skull into the brain (the transcranial pathway).

This study aims to differentiate these two mechanisms in healthy volunteers. Participants will complete two separate MRI scanning sessions. In one session, a local anesthetic (lidocaine) will be applied to numb the skin over the forehead (specifically the supraorbital nerve branch) to temporarily block the peripheral nerve signals. In the other session, no anesthesia will be used. During both sessions, participants will receive active direct current eTNS (DC-eTNS) and a sham (inactive) stimulation while inside a 3T MRI scanner.

Researchers will simultaneously measure brain activity (fMRI) and physiological signals (breathing and heart rate). By comparing the brain and bodily responses between the anesthetized and non-anesthetized conditions, the study seeks to determine exactly how eTNS signals travel to and affect the brainstem, cortex, and autonomic nervous system.

Conditions

  • Healthy Volunteers
  • Neurophysiology
  • fMRI Research

Interventions

DRUG

Topical Lidocaine

Application of a local anesthetic over the forehead targeting the supraorbital nerve branch prior to the MRI scan, intended to block peripheral transcutaneous nerve conduction.

DEVICE

Direct Current eTNS (DC-eTNS)

Active direct current electrical stimulation applied via electrodes on the forehead. The stimulation is synchronized with a 7-minute and 30-second BOLD fMRI sequence, which includes a 15-second current ramp-up phase at the beginning and a 15-second current ramp-down phase at the end.

DEVICE

Sham DC-eTNS

An inactive or sensory-matched sham stimulation administered during a 7-minute and 30-second BOLD fMRI sequence to serve as a baseline comparator.

Sponsors & Collaborators

  • Xidian University

    lead OTHER

Study Design

Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
SINGLE
Model
CROSSOVER

Eligibility

Min Age
18 Years
Max Age
35 Years
Sex
ALL
Healthy Volunteers
Yes

Timeline & Regulatory

Start
2026-06-21
Primary Completion
2026-07-05
Completion
2026-07-05

Countries

  • China

Study Locations

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Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT07657260 on ClinicalTrials.gov