NCT06016686 · University of Minnesota
Microelectrode Recordings From the Vagus Nerve in Awake Humans
What this study is about
This Anchillary project uses a refined technique of ultrasound-guided microneurography of the human cervical vagus nerve, an approach developed by Professor Vaughan Macefield and used safely to-date in 44 prior study participants.
View original scientific description
This Anchillary project uses a refined technique of ultrasound-guided microneurography of the human cervical vagus nerve, an approach developed by Professor Vaughan Macefield and used safely to-date in 44 prior study participants. The overall goal of this project is to build upon prior data obtained using this approach by undertaking a detailed neurophysiological investigation of the human vagus nerve and to identify the nerve fibers activated during vagal nerve stimulation (VNS) in participants with implanted VNS devices in response to different stimulation parameters. In addition to providing data in unprecedented detail into the physiology of the human vagus nerve, this project will investigate different stimulus intensities, durations and frequencies that differentially excite myelinated and unmyelinated nerve fibers. These results will inform the CSP and guide future development of novel neural interfaces for VNS for various clinical applications.
Interventions
OTHER
VNS stimulation and intraneural recordings
A minimum of three stimulation frequencies (1, 10 and 30 Hz), each up to 60s in duration, will be delivered via the VNS device. Intraneural recordings proximal or distal to the VNS electrodes during delivery of VNS will be performed. Approximately two to five fascicles will be explored in each nerve.
OTHER
Record multi-unit activity from intraneural sites
Perform a more detailed vagal nerve mapping study by recording from single nerve fibers, including those fibers supplying the heart, lungs, airways and other end-organs. The investigators shall perform functional mapping of the left and right vagus nerves, such as those with cardiac-related and/or respiratory-related neural activity. The research team will also record activity from other nearby fibers to map the differences in neurological behavior in fascicles that control the heart, lungs, airways and other systems.
Primary outcome measures
identify action potential morphology of specific fibers activated by vagal nerve stimulation (VNS)
Time frame: 4 hours
assessing vagal nerve activity in epilepsy participants during and in the absence of stimulation. Labchart; spike histogram module
identify ratio of myelinated fibers in specific fibers activated by vagal nerve stimulation (VNS)
Time frame: 4 hours
assessing vagal nerve activity in epilepsy participants during and in the absence of stimulation. Labchart; spike histogram module. Whether a nerve fiber is (un)myelinated can be determined by visual inspection. Myelinated fibers typically produce "a positive-going narrow spike profile.
physiological identification of the specific fibers activated by vagal nerve stimulation (VNS)
Time frame: 4 hours
assessing vagal nerve activity in epilepsy participants during and in the absence of stimulation. Labchart; spike histogram module. use of tracing and nerve recordings analysis to identify the types of nerves
identify firing rates of the specific fibers activated by vagal nerve stimulation (VNS)
Time frame: 4 hours
assessing vagal nerve activity in epilepsy participants during and in the absence of stimulation. Labchart; spike histogram module. in Hertz
identify stimulus current required to activate specific fibers activated by vagal nerve stimulation (VNS)
Time frame: 4 hours
assessing vagal nerve activity in epilepsy participants during and in the absence of stimulation. Labchart; spike histogram module. in milli-amps
differences in firing rates of cardiac parasympathetic vagal activity
Time frame: 4 hours
compare any changes in parasympathetic vagal activity with participants who have not been implanted with a vagal nerve stimulator (Non-VNS Participants). Labchart; spike histogram module. Unit: Hz.
Discharge variability of cardiac parasympathetic nerve fibers
Time frame: 4 hours
Vagal nerve stimulator device. Coefficient of variation, %
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- The participant is greater than or equal to (≥)18 years and is less than or equal to (≤) 40 years of age
- English speaking
- Medicare covered or equivalent health insurance from a partner country
Exclusion criteria
- Smokes and is unwilling to abstain from smoking on the day of the experiment.
- Inability or unwillingness to provide written informed consent.
- Individuals with difficulty standing unassisted for 5 minutes during the tilt-table testing
- Individuals found to have a significant carotid artery plaque or intima-media thickness \> 1 mm as assessed by ultrasonography during the ultrasound-screening steps of the study visit
- Vagus nerve not visible on ultrasound
- VNS electrodes are not in a suitable location to allow for microelectrode insertion
- Any other clinical reasons deemed by the investigators
Where
- Minneapolis, Minnesota
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Apr 20, 2026 · Source of record for eligibility and locations