Differentiating the Transcutaneous and Transcranial Mechanisms of Direct Current Trigeminal Nerve Stimulation on Brainstem and Autonomic Function: A Randomized, Sham-Controlled, Crossover fMRI Study With Local Anesthesia
试验速览
- 阶段
- 不适用
- 状态
- 招募中
- 入组人数
- 25
- 试验地点
- 1
研究概览
简要总结
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.
详细描述
This is an exploratory, randomized, sham-controlled, crossover functional neuroimaging study designed to isolate and differentiate the transcutaneous (peripheral nerve mediated) versus transcranial (direct electrical penetration) mechanisms of direct current Trigeminal Nerve Stimulation (DC-eTNS).
Healthy participants will undergo two separate study sessions in a randomized order:
Anesthesia Condition: Local anesthesia (Lidocaine) will be applied to the skin area corresponding to the supraorbital branch of the trigeminal nerve to temporarily block somatosensory afferent pathways.
No-Anesthesia Condition: The participant will undergo the same procedures without the application of local anesthesia.
During each session, participants will be scanned in a 3T MRI scanner. The imaging protocol will consist of a high-resolution structural T1-weighted scan, followed by two functional Blood Oxygenation Level-Dependent (BOLD) sequences: one for active DC-eTNS and one for Sham stimulation. Each functional BOLD sequence will last for 7 minutes and 30 seconds. The active DC-eTNS stimulation paradigm includes a 15-second current ramp-up phase at the beginning and a 15-second current ramp-down phase at the end to ensure participant comfort and safety.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Crossover
- 主要目的
- Basic Science
- 盲法
- Single (Outcomes Assessor)
入排标准
- 年龄范围
- 18 Years 至 35 Years（Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Healthy volunteers, aged 18 to 40 years old.
- •Right-handed.
- •Generally healthy with no history of neurological, psychiatric, or severe cardiovascular diseases.
- •Normal physical and neurological examinations.
- •Capable of understanding the study procedures and voluntarily signing the written informed consent form.
排除标准
- •Known allergy, hypersensitivity, or adverse reactions to Lidocaine or other amide-type local anesthetics. (Crucial for this specific study design)
- •Contraindications to MRI scanning (e.g., claustrophobia, cardiac pacemakers, artificial cochlea, metallic braces, or any other ferromagnetic implants).
- •Female participants who are pregnant, lactating, or suspect they might be pregnant.
- •Contraindications to transcranial or transcutaneous electrical stimulation (e.g., personal or family history of epilepsy/seizures, implanted brain stimulators).
- •Any active skin disease, inflammation, lesions, cuts, or abrasions on the forehead (specifically over the supraorbital area), which could alter electrical impedance or anesthetic absorption.
- •History of trigeminal neuralgia, facial nerve palsy, or chronic facial pain. Current or recent (within the past month) use of any medications known to affect the central nervous system, autonomic nervous system, or pain perception (e.g., analgesics, antidepressants, beta-blockers, or sedatives).
- •History of substance abuse, heavy smoking, or excessive daily consumption of alcohol or caffeine.
- •Irregular sleep patterns, shift work, or severe sleep deprivation within 24 hours prior to the scanning sessions.