Neural Mechanisms of Interpersonal Expectations on Negative Affect
Trustees of Dartmouth College
190 participants
Sep 1, 2025
INTERVENTIONAL
Conditions
Summary
The goal of this clinical trial is to learn whether non-invasive brain stimulation, called transcranial temporal interference stimulation (tTIS), can reduce negative affect, and how expectations shaped by care providers influence these effects. The main questions this study aims to answer are: (1)Does active tTIS reduce negative affect more effectively than sham (inactive) tTIS? (2)Do positive treatment expectations enhance the effects compared to negative expectations? Participants will: (1) Receive either active or sham tTIS. (2) Be provided with positive or negative messaging regarding treatment effectiveness. (3) Interact with care providers and complete assessments measuring negative affect and physiological responses.
Eligibility
Inclusion Criteria1
- 'Doctors' are recruited from medical students at the Geisel School of Medicine and resident physicians at Dartmouth Hitchcock Medical Center (DHMC).
Exclusion Criteria10
- No self-reported current or history of depression, bipolar disorder, or other psychiatric diagnosis
- No self-reported current seizure disorder (i.e., seizure within past 10 years), or history of stroke or other major neurological diagnosis that can cause cognitive impairment
- No self-reported current chronic pain, or acute pain within three months of the study period
- No current migraine disorder (i.e., 15 headache days or more in 1 month)
- No use of central nervous system-effective medication or other medication for neurological/psychiatric treatment
- No self-reported substance abuse within the last six months
- No contraindication to MRI or tTIS (e.g., pregnancy, claustrophobia, pacemakers, ear/cochlear implants, shrapnel injuries, clips, or other ferromagnetic/electrical objects/devices, diagnosed brain abnormality such as tumor, or skin lesions on the scalp.)
- No contraindications for induced pain (e.g., no heart disease, high blood pressure, heart surgery, heart problems of any kind, severe asthma, respiratory problems of any kind, fibromyalgia, Raynaud's Syndrome or Disease, chronic pain, diabetes)
- Participants must be capable of performing experimental tasks (e.g., are able to read), are fluent or native speakers of English
- Participants must be able to tolerate the maximum level of thermal pain stimuli (for thermal stimuli)
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Interventions
Participants receive active tTIS, with two signals set at 2000 Hz and 2080 Hz, creating an 80 Hz interference beat targeting the anterior/mid-cingulate cortex (aMCC). Stimulation is delivered at 2 mA for 20 minutes. The stimulation is combined with a positive social placebo intervention delivered by the care provider. Participants complete three multimodal negative affect tasks (MNAT) before and after the stimulation.
Participants receive sham tTIS, using two identical 2000 Hz signals that produce no low-frequency interference. The device mimics active parameters (2 mA, 20 minutes) without delivering effective stimulation. The sham stimulation is paired with a positive social placebo intervention. Participants complete three MNAT tasks before and after the session.
Participants receive active tTIS (2000 Hz and 2080 Hz signals, 2 mA, 20 minutes) combined with a negative social placebo intervention (neutral or skeptical messaging about treatment efficacy). Participants complete three MNAT tasks before and after the stimulation.
Participants receive sham tTIS (identical 2000 Hz signals, mimicking active stimulation) combined with a negative social placebo intervention. Participants complete three MNAT tasks before and after the session.
Participants receive sham tTIS (brief 15-second stimulation followed by no current) paired with a positive social placebo intervention. Participants complete three MNAT tasks before and after the session.
Participants receive sham tTIS (brief 15-second stimulation, then no current) without any placebo intervention. Participants complete three MNAT tasks before and after the session.
Locations(1)
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NCT06980090