Transcranial Electric Stimulation
Conditions
Brief summary
This study is to find out whether and how a type of non-invasive electrical brain stimulation called transcranial electrical stimulation with temporal interference (TES-TI) can temporarily change brain activity in healthy adults. A structural MRI scan will be used to customize where the stimulation electrodes are placed for each participant to deliver TES-TI during three afternoon sessions at rest with eyes closed. Brain activity is recorded with high-density EEG. Up to 24 participants will be enrolled and on study for 3 to 12 weeks.
Detailed description
This is an experimental study using a within-subject, single-blind, randomized, counterbalanced crossover design in which each participant serves as their own control. Healthy adults will complete (or provide an existing) structural MRI scan (T1/T2) to support individualized electric-field modeling and personalized montage optimization for thalamic targeting, followed by three afternoon stimulation sessions with simultaneous high-density EEG during eyes-closed wakefulness; sessions will be scheduled on separate days at least one week apart. Each session includes four stimulation conditions administered in randomized/counterbalanced order, with each condition consisting of a fixed 3-minute pre-stimulation baseline, 3-minute stimulation period, and 3-minute post-stimulation recording to enable STIM-PRE and POST-PRE comparisons. * Session A tests amplitude-modulation specificity (in-phase mTI, a mixed unipolar+HF condition with the same montage/current, a carrier-only HF control, and sham) * Session B benchmarks in-phase mTI against unipolar TES-TI at 5 mA and 8 mA (plus sham); and * Session C characterizes frequency dependence of in-phase mTI (10, 50, 130 Hz; plus sham). Primary Objectives: 1. Determine whether active multipolar TES-TI (mTI) produces envelope-driven EEG effects (primary contrast: STIM-PRE) by comparing in-phase mTI to SHAM, to a carrier-only no-envelope high-frequency (HF) control, and to a mixed unipolar+HF condition (same montage/current; one pair as unipolar TES-TI producing an AM envelope, the other pair as a non-interacting HF carrier with no envelope contribution). 2. Benchmark mTI against unipolar TES-TI across stimulation intensity by comparing in-phase mTI to unipolar TES-TI at 5 mA and 8 mA, each evaluated relative to SHAM (primary contrast: STIM-PRE), and estimating effect sizes to inform future study design. 3. Characterize envelope-frequency dependence of in-phase mTI effects by comparing EEG spectral power changes across 10, 50, and 130 Hz conditions (each relative to SHAM; primary contrast: STIM-PRE). Secondary Objectives: 4. Assess persistence of stimulation-related EEG changes by quantifying post-stimulation effects (POST-PRE) across conditions (in-phase, mixed unipolar+HF, HF, unipolar) and sessions
Interventions
DEVICETES-TI with hdEEG
4 conditions per session. Each condition will follow a standardized block structure consisting of 3 minutes pre-stimulation baseline, 3 minutes stimulation, and 3 minutes post-stimulation recording (PRE, STIM, POST)
Sponsors
University of Wisconsin, Madison
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
SINGLE (Subject)
Intervention model description
Within-subject, single-blind, randomized, counterbalanced crossover design in which each participant serves as their own control.
Eligibility
Sex/Gender
ALL
Age
18 Years to 50 Years
Healthy volunteers
Yes
Inclusion criteria
* Medically healthy (based on self-report and study team review) * U.S. citizen or holding permanent resident status * English-speaking (able to provide consent and complete questionnaires)
Exclusion criteria
* Current or past history of clinically significant neurological disorder or acquired neurological disease (e.g., stroke, traumatic brain injury), including intracranial lesions (including clinically significant findings identified on the structural MRI) * History of inpatient psychiatric hospitalization * History of head trauma resulting in prolonged loss of consciousness; or a history of \>3 grade I concussions * Current poorly controlled headaches, including intractable or frequent migraines * Any systemic illness or unstable medical condition that may cause a medical emergency in case of a provoked seizure (cardiac malformation, cardiac dysrhythmia, asthma, etc.) * History of seizures, diagnosis of epilepsy, history of abnormal (epileptiform) EEG, or family history of treatment resistant epilepsy except for a single seizure of benign etiology (e.g. febrile seizures) in the judgment of a board-certified neurologist * Possible pregnancy or plan to become pregnant in the next 6 months (self reported) * Any metal in the head or body * Any medical devices or implants (i.e. cardiac pacemaker, medication infusion pump, cochlear implant, vagal nerve stimulator) * Dental implants * Permanent retainers * Any hair braid, dreadlocks, hair pieces, or extensions which cannot be taken out before the study sessions * Any head coverings or headdress that participant feels uncomfortable removing for the purposes of study sessions * Current use of medications known to substantially lower seizure threshold, specifically chlorpromazine, clozapine, bupropion, clomipramine, or maprotiline; or other medications at doses known to substantially lower seizure threshold in the judgment of the PI * Active scalp lesions, broken skin, or skin conditions at planned electrode sites that would preclude safe electrode application * Claustrophobia (a fear of small or closed places) * Back problems that would prevent lying flat for up to two hours
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in band-limited, topography-resolved EEG spectral power during stimulation for conditions in Session A | data collected for 3 minutes prior to stimulation and 3 minutes during stimulation for each of 4 conditions during Session A (approximately 3 hours long) | Change in band-limited, topography-resolved EEG spectral power during stimulation (STIM-PRE) for in-phase mTI compared to SHAM, HF control, and the mixed unipolar+HF condition. |
| Change in band-limited, topography-resolved EEG spectral power during stimulation for conditions in Session B | data collected for 3 minutes prior to stimulation and 3 minutes during stimulation for each of 4 conditions during Session B (approximately 3 hours long) | Change in band-limited, topography-resolved EEG spectral power during stimulation (STIM-PRE) for in-phase mTI compared to unipolar TES-TI at 5 mA, and 8 mA, relative to SHAM. |
| Change in band-limited, topography-resolved EEG spectral power during stimulation for conditions in Session C | data collected for 3 minutes prior to stimulation and 3 minutes during stimulation for each of 4 conditions during Session C (approximately 3 hours long) | Change in band-limited, topography-resolved EEG spectral power during stimulation (STIM-PRE) for in-phase mTI at 10 Hz, 50 Hz, and 130 Hz, relative to SHAM. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in band-limited, topography-resolved EEG spectral power in the post-stimulation interval (POST-PRE) across all tested conditions | data collected for 3 minutes prior to stimulation and 3 minutes post stimulation for each of 4 conditions during each of 3 sessions (each session is approximately 3 hours long, with at least one week between sessions) | Change in band-limited, topography-resolved EEG spectral power in the post-stimulation interval (POST-PRE) across all tested conditions (in-phase mTI, mixed unipolar+HF, HF control, unipolar 5 mA, unipolar 8 mA; and 10/50/130 Hz where applicable), each evaluated relative to SHAM. |
Countries
United States
Contacts
CONTACTMINT Study Team
PRINCIPAL_INVESTIGATORLarissa Albantakis, PhD
UW School of Medicine and Public Health
Outcome results
None listed