Temporal Interference Methods for Non-invasive Deep Brain Stimulation, Study 1.1

July 8, 2026 updated by: Joshua Brown, PHD, Indiana University

Temporal Interference Methods for Non-invasive Deep Brain Stimulation

In its totality, this grant aims to develop a line of research using temporal interference (TI) electrical neurostimulation technology to understand the causal role of deep brain structures in cognition. In the short term, the investigators aim to validate and characterize the effects of TI on brain activity as measured by fMRI and demonstrate its ability to focally stimulate deep brain regions without affecting overlying cortex. In the longer term, investigators aim to use these data to resolve longstanding debates about the function of deeper brain regions and lay the foundation for future clinical applications of TI for treating addiction, Obsessive-Compulsive Disorder (OCD), Parkinson's disease, and other disorders involving deep brain dysfunction. The grant supports 2 distinct aims, each of which will be evaluated through a series of independent studies.

Study Overview

Detailed Description

Through the grant's duration, the investigators hypothesize that temporal interference (TI) electrical neurostimulation will be well tolerated and effective at focally manipulating deep brain activity as measured by functional MRI (fMRI) BOLD signals. The investigators will investigate whether TI stimulation can increase BOLD activity in targeted deep brain regions including the nucleus accumbens (NAcc) and dorsal anterior cingulate cortex (dACC), and whether this stimulation can influence cognitive functions controlled by these regions. TI works by applying alternating currents of slightly different frequencies through multiple electrode pairs, creating an interference pattern that can stimulate deep brain regions without significantly affecting superficial cortical areas. This method is similar to traditional transcranial direct current stimulation (tDCS), however TI can stimulate deeper brain structures that tDCS cannot reach effectively. The study is broken up into two main aims with multiple sub-studies. In Aim 1, the investigators will characterize the effects of TI on fMRI BOLD signals, test different beat frequencies, and compare TI effects in the nucleus accumbens versus dorsal anterior cingulate cortex. In Aim 2, the investigators will apply TI to the dorsal anterior cingulate cortex to test causal theories about its role in cognitive control, conflict monitoring, risk avoidance, and foraging behavior using established cognitive tasks while subjects undergo fMRI scanning.

Study 1.1 (Aim 1, Study 1) will test the ability to focally activate the nucleus accumbens without activating the overlying cortex, and also its effects on functional connectivity. Healthy subjects (n=30) will present for a single study visit during which they will be placed in the fMRI scanner and administered a temporal interference protocol. Specifically, subjects will have two pairs of carbon fiber electrodes attached to the scalp with conductive gel. They will receive one 8-minute block of stimulation at 2mA per electrode pair. The stimulation sequence will be 2 minutes on, 2 minutes off, 2 minutes on, and 2 minutes off with 30 second ramp up and ramp down beginning at the start of each 2-minute period. The first block will apply active TI stimulation with 2000Hz in one channel and 2020Hz in the other channel. The second block will be a sham TI stimulation, identical to the first block but with the "on" condition immediately ramping down as soon as it reaches 2mA after ramp up. The third and fourth blocks will be identical to the first and second blocks, except that both electrode pairs will stimulate at 2000Hz, resulting in a "NO-TI active" and "NO-TI sham" conditions. The order of blocks, and whether the "on" or "off" condition occurs first within a block, will be counterbalanced across subjects.

Study Type

Interventional

Enrollment (Actual)

30

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

    • Indiana
      • Bloomington, Indiana, United States, 47408
        • Indiana University Bloomington, Imaging Research Facility

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Between the ages of 18 and 50
  • Must have at least a 6th grade education
  • Ability to speak and read English for all phases

Exclusion Criteria:

  • Currently taking psychotropic medications for ADHD, other mental illness, or medications for cancer
  • History of epilepsy or seizure disorders
  • History of migraines or other neurological syndromes
  • History of AIDS (due to potential cognitive deficits)
  • History of head trauma or cognitive impairments
  • Personal experiences consistent with symptoms of psychosis (e.g., hallucinations, delusions of control or special powers)
  • History of skull defects (e.g., holes bored into the skull or known cranial fissures)
  • Metal implants in the head or under the scalp
  • Does not meet fMRI safety screening criteria (e.g., metal implants in the body, permanent jewelry, tattoos on the head or neck)
  • Uses an intrauterine device (IUD) for birth control and cannot provide documentation to verify MRI safety
  • Pregnancy (self-reported; no pregnancy test administered)
  • Weight over 440 lbs (scanner weight limit)
  • Presence of pacemakers

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: NAcc TI Active, then NAcc TI Sham, then NAcc No-TI Active, then NAcc No-TI Sham
Participants in this Arm receive temporal interference (TI) electrical stimulation with two pairs of carbon fiber electrodes in this order: NAcc TI Active, then NAcc TI Sham, then NAcc No-TI Active, then NAcc No-TI Sham.

Non-invasive electrical brain stimulation delivered through two sets of scalp electrodes using alternating current frequencies (e.g., 2000 Hz and 2020 Hz) at up to 2 mA per electrode. This stimulation creates a beat frequency interference pattern (e.g., 20 Hz) that focally stimulates deep brain regions without activating overlying cortex.

For the NAcc TI Active condition, 2000Hz will be administered in one channel and 2020Hz in the other. These frequencies will be administered in 2 minutes on/2 minutes off cycles with a 30 second ramp up and ramp down beginning at the start of each 2 minute period.

Other Names:
  • TI Electrical Neurostimulation
  • TI Neurostimulation

Non-invasive electrical brain stimulation delivered through two sets of scalp electrodes using alternating current frequencies (e.g., 2000 Hz and 2020 Hz) at up to 2 mA per electrode. This stimulation creates a beat frequency interference pattern (e.g., 20 Hz) that focally stimulates deep brain regions without activating overlying cortex.

For the NAcc TI Sham condition, 2000Hz will be administered in one channel and 2020Hz in the other. These frequencies will be administered in 2 minutes on/2 minutes off cycles, however, instead of the 30 second ramp up and ramp down at the beginning of each 2 minute period (as seen in the Active TI condition), the stimulation in the NAcc TI Sham condition will immediately ramp down as soon as it reaches 2mA after ramp up.

Other Names:
  • TI Electrical Neurostimulation
  • TI Neurostimulation

Non-invasive electrical brain stimulation delivered through two sets of scalp electrodes using the same current frequencies at up to 2 mA per electrode.

For the NAcc No-TI Active condition, 2000Hz will be administered in both channels. These frequencies will be administered in 2 minutes on/2 minutes off cycles with a 30 second ramp up and ramp down beginning at the start of each 2 minute period.

Other Names:
  • TI Electrical Neurostimulation
  • TI Neurostimulation

Non-invasive electrical brain stimulation delivered through two sets of scalp electrodes using the same current frequencies at up to 2 mA per electrode.

For the NAcc No-TI Sham condition, 2000Hz will be administered in both channels. These frequencies will be administered in 2 minutes on/2 minutes off cycles, however, instead of the 30 second ramp up and ramp down at the beginning of each 2 minute period (as seen in the NAcc No-TI Active condition), the stimulation in the NAcc No-TI Sham condition will immediately ramp down as soon as it reaches 2mA after ramp up.

Other Names:
  • TI Electrical Neurostimulation
  • TI Neurostimulation
Active Comparator: NAcc No-TI Active, then NAcc No-TI Sham, then NAcc TI Active, then NAcc TI Sham
Participants in this Arm receive temporal interference (TI) electrical stimulation with two pairs of carbon fiber electrodes in this order: NAcc No-TI Active, then NAcc No-TI Sham, then NAcc TI Active, then NAcc TI Sham.

Non-invasive electrical brain stimulation delivered through two sets of scalp electrodes using alternating current frequencies (e.g., 2000 Hz and 2020 Hz) at up to 2 mA per electrode. This stimulation creates a beat frequency interference pattern (e.g., 20 Hz) that focally stimulates deep brain regions without activating overlying cortex.

For the NAcc TI Active condition, 2000Hz will be administered in one channel and 2020Hz in the other. These frequencies will be administered in 2 minutes on/2 minutes off cycles with a 30 second ramp up and ramp down beginning at the start of each 2 minute period.

Other Names:
  • TI Electrical Neurostimulation
  • TI Neurostimulation

Non-invasive electrical brain stimulation delivered through two sets of scalp electrodes using alternating current frequencies (e.g., 2000 Hz and 2020 Hz) at up to 2 mA per electrode. This stimulation creates a beat frequency interference pattern (e.g., 20 Hz) that focally stimulates deep brain regions without activating overlying cortex.

For the NAcc TI Sham condition, 2000Hz will be administered in one channel and 2020Hz in the other. These frequencies will be administered in 2 minutes on/2 minutes off cycles, however, instead of the 30 second ramp up and ramp down at the beginning of each 2 minute period (as seen in the Active TI condition), the stimulation in the NAcc TI Sham condition will immediately ramp down as soon as it reaches 2mA after ramp up.

Other Names:
  • TI Electrical Neurostimulation
  • TI Neurostimulation

Non-invasive electrical brain stimulation delivered through two sets of scalp electrodes using the same current frequencies at up to 2 mA per electrode.

For the NAcc No-TI Active condition, 2000Hz will be administered in both channels. These frequencies will be administered in 2 minutes on/2 minutes off cycles with a 30 second ramp up and ramp down beginning at the start of each 2 minute period.

Other Names:
  • TI Electrical Neurostimulation
  • TI Neurostimulation

Non-invasive electrical brain stimulation delivered through two sets of scalp electrodes using the same current frequencies at up to 2 mA per electrode.

For the NAcc No-TI Sham condition, 2000Hz will be administered in both channels. These frequencies will be administered in 2 minutes on/2 minutes off cycles, however, instead of the 30 second ramp up and ramp down at the beginning of each 2 minute period (as seen in the NAcc No-TI Active condition), the stimulation in the NAcc No-TI Sham condition will immediately ramp down as soon as it reaches 2mA after ramp up.

Other Names:
  • TI Electrical Neurostimulation
  • TI Neurostimulation
Active Comparator: NAcc TI Sham, then NAcc TI Active, then NAcc No-TI Sham, then NAcc No-TI Active
Participants in this Arm receive temporal interference (TI) electrical stimulation with two pairs of carbon fiber electrodes in this order: NAcc TI Sham, then NAcc TI Active, then NAcc No-TI Sham, then NAcc No-TI Active.

Non-invasive electrical brain stimulation delivered through two sets of scalp electrodes using alternating current frequencies (e.g., 2000 Hz and 2020 Hz) at up to 2 mA per electrode. This stimulation creates a beat frequency interference pattern (e.g., 20 Hz) that focally stimulates deep brain regions without activating overlying cortex.

For the NAcc TI Active condition, 2000Hz will be administered in one channel and 2020Hz in the other. These frequencies will be administered in 2 minutes on/2 minutes off cycles with a 30 second ramp up and ramp down beginning at the start of each 2 minute period.

Other Names:
  • TI Electrical Neurostimulation
  • TI Neurostimulation

Non-invasive electrical brain stimulation delivered through two sets of scalp electrodes using alternating current frequencies (e.g., 2000 Hz and 2020 Hz) at up to 2 mA per electrode. This stimulation creates a beat frequency interference pattern (e.g., 20 Hz) that focally stimulates deep brain regions without activating overlying cortex.

For the NAcc TI Sham condition, 2000Hz will be administered in one channel and 2020Hz in the other. These frequencies will be administered in 2 minutes on/2 minutes off cycles, however, instead of the 30 second ramp up and ramp down at the beginning of each 2 minute period (as seen in the Active TI condition), the stimulation in the NAcc TI Sham condition will immediately ramp down as soon as it reaches 2mA after ramp up.

Other Names:
  • TI Electrical Neurostimulation
  • TI Neurostimulation

Non-invasive electrical brain stimulation delivered through two sets of scalp electrodes using the same current frequencies at up to 2 mA per electrode.

For the NAcc No-TI Active condition, 2000Hz will be administered in both channels. These frequencies will be administered in 2 minutes on/2 minutes off cycles with a 30 second ramp up and ramp down beginning at the start of each 2 minute period.

Other Names:
  • TI Electrical Neurostimulation
  • TI Neurostimulation

Non-invasive electrical brain stimulation delivered through two sets of scalp electrodes using the same current frequencies at up to 2 mA per electrode.

For the NAcc No-TI Sham condition, 2000Hz will be administered in both channels. These frequencies will be administered in 2 minutes on/2 minutes off cycles, however, instead of the 30 second ramp up and ramp down at the beginning of each 2 minute period (as seen in the NAcc No-TI Active condition), the stimulation in the NAcc No-TI Sham condition will immediately ramp down as soon as it reaches 2mA after ramp up.

Other Names:
  • TI Electrical Neurostimulation
  • TI Neurostimulation
Active Comparator: NAcc No-TI Sham, then NAcc No-TI Active, then NAcc TI Sham, then NAcc TI Active
Participants in this Arm receive temporal interference (TI) electrical stimulation with two pairs of carbon fiber electrodes in this order: NAcc No-TI Sham, then NAcc No-TI Active, then NAcc TI Sham, then NAcc TI Active.

Non-invasive electrical brain stimulation delivered through two sets of scalp electrodes using alternating current frequencies (e.g., 2000 Hz and 2020 Hz) at up to 2 mA per electrode. This stimulation creates a beat frequency interference pattern (e.g., 20 Hz) that focally stimulates deep brain regions without activating overlying cortex.

For the NAcc TI Active condition, 2000Hz will be administered in one channel and 2020Hz in the other. These frequencies will be administered in 2 minutes on/2 minutes off cycles with a 30 second ramp up and ramp down beginning at the start of each 2 minute period.

Other Names:
  • TI Electrical Neurostimulation
  • TI Neurostimulation

Non-invasive electrical brain stimulation delivered through two sets of scalp electrodes using alternating current frequencies (e.g., 2000 Hz and 2020 Hz) at up to 2 mA per electrode. This stimulation creates a beat frequency interference pattern (e.g., 20 Hz) that focally stimulates deep brain regions without activating overlying cortex.

For the NAcc TI Sham condition, 2000Hz will be administered in one channel and 2020Hz in the other. These frequencies will be administered in 2 minutes on/2 minutes off cycles, however, instead of the 30 second ramp up and ramp down at the beginning of each 2 minute period (as seen in the Active TI condition), the stimulation in the NAcc TI Sham condition will immediately ramp down as soon as it reaches 2mA after ramp up.

Other Names:
  • TI Electrical Neurostimulation
  • TI Neurostimulation

Non-invasive electrical brain stimulation delivered through two sets of scalp electrodes using the same current frequencies at up to 2 mA per electrode.

For the NAcc No-TI Active condition, 2000Hz will be administered in both channels. These frequencies will be administered in 2 minutes on/2 minutes off cycles with a 30 second ramp up and ramp down beginning at the start of each 2 minute period.

Other Names:
  • TI Electrical Neurostimulation
  • TI Neurostimulation

Non-invasive electrical brain stimulation delivered through two sets of scalp electrodes using the same current frequencies at up to 2 mA per electrode.

For the NAcc No-TI Sham condition, 2000Hz will be administered in both channels. These frequencies will be administered in 2 minutes on/2 minutes off cycles, however, instead of the 30 second ramp up and ramp down at the beginning of each 2 minute period (as seen in the NAcc No-TI Active condition), the stimulation in the NAcc No-TI Sham condition will immediately ramp down as soon as it reaches 2mA after ramp up.

Other Names:
  • TI Electrical Neurostimulation
  • TI Neurostimulation

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change From Baseline (no Stimulation) in Brain Activity in the Nucleus Accumbens During Active Versus Sham Stimulation
Time Frame: During fMRI scanning for each study session (active and sham stimulation), approximately 60 minutes
Brain activity in the nucleus accumbens was measured using functional magnetic resonance imaging (fMRI) during active temporal interference (TI) brain stimulation compared to sham stimulation. Activity change from baseline (no stimulation) was quantified using region-of-interest (ROI) beta estimates extracted from the nucleus accumbens. The beta estimates were derived from blood-oxygen-level-dependent (BOLD) signal changes measured during fMRI and reflect the magnitude of task-related neural activation within the ROI. Higher beta values indicate greater task-related activation. Whole-brain voxelwise analyses did not identify statistically significant activation clusters after correction for multiple comparisons; therefore, descriptive ROI-level beta estimates are reported.
During fMRI scanning for each study session (active and sham stimulation), approximately 60 minutes

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change From Baseline (no Stimulation) in Brain Activity in the Nucleus Accumbens During No-TI Active Versus No-TI Sham High-frequency Stimulation
Time Frame: During fMRI scanning for each study session (active and sham no-TI stimulation conditions), approximately 60 minutes
Brain activity in the nucleus accumbens was measured using functional magnetic resonance imaging (fMRI) during no-temporal interference (no-TI) control stimulation, in which both electrode pairs delivered the same frequency. Change in activity from baseline (no stimulation) was quantified using region-of-interest (ROI) beta estimates extracted from the nucleus accumbens during NO-TI active versus NO-TI sham high-frequency stimulation to determine whether high-frequency stimulation alone altered brain activity. The beta estimates were derived from blood-oxygen-level-dependent (BOLD) signal changes measured during fMRI and reflect the magnitude of task-related neural activation within the ROI. Higher beta values indicate greater task-related activation. Whole-brain voxelwise analyses did not identify statistically significant activation differences after correction for multiple comparisons; therefore, descriptive ROI-level beta estimates are reported.
During fMRI scanning for each study session (active and sham no-TI stimulation conditions), approximately 60 minutes
Change From Baseline (no Stimulation) in Brain Activity in the Nucleus Accumbens During Active TI Stimulation Versus Active No-TI Stimulation
Time Frame: During fMRI scanning for each study session (active TI and active no-TI stimulation conditions), approximately 60 minutes
Brain activity in the nucleus accumbens was compared between active temporal interference (TI) stimulation and active high-frequency no-temporal interference (no-TI) stimulation using functional magnetic resonance imaging (fMRI). Change in activity from baseline (no stimulation) was quantified using region-of-interest (ROI) beta estimates extracted from the nucleus accumbens to determine whether TI stimulation produced greater task-related activation than high-frequency stimulation alone. The beta estimates were derived from blood-oxygen-level-dependent (BOLD) signal changes measured during fMRI and reflect the magnitude of task-related neural activation within the ROI. Higher beta values indicate greater task-related activation. Whole-brain voxelwise analyses did not identify statistically significant activation differences after correction for multiple comparisons; therefore, descriptive ROI-level beta estimates are reported.
During fMRI scanning for each study session (active TI and active no-TI stimulation conditions), approximately 60 minutes
Change in Brain Connectivity Between the Nucleus Accumbens and Other Brain Regions During Stimulation
Time Frame: During fMRI scanning for each study session (active and sham stimulation conditions), approximately 60 minutes
Functional connectivity between the nucleus accumbens and other brain regions was planned to be evaluated using fMRI-based psycho-physiological interaction (PPI) analyses during active versus sham temporal interference (TI) stimulation. Higher correlation values indicate stronger functional connectivity between brain regions. The primary test statistic was the whole-brain interaction term between seed-region BOLD activity and stimulation condition (active vs. sham TI). This analysis was not performed because no statistically significant activation clusters were identified from which to define a seed region.
During fMRI scanning for each study session (active and sham stimulation conditions), approximately 60 minutes

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Investigators

  • Principal Investigator: Joshua W Brown, PhD, Indiana University, Bloomington

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

November 12, 2025

Primary Completion (Actual)

February 2, 2026

Study Completion (Actual)

February 2, 2026

Study Registration Dates

First Submitted

September 29, 2025

First Submitted That Met QC Criteria

October 7, 2025

First Posted (Actual)

October 10, 2025

Study Record Updates

Last Update Posted (Actual)

August 3, 2026

Last Update Submitted That Met QC Criteria

July 8, 2026

Last Verified

June 1, 2026

More Information

Terms related to this study

Other Study ID Numbers

  • 26941, Study 1.1
  • 1R21MH140210-01 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

Yes

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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