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Neural Mechanisms of Interpersonal Expectations on Negative Affect
Sponsor: Trustees of Dartmouth College
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.
Key Details
Gender
All
Age Range
18 Years - 55 Years
Study Type
INTERVENTIONAL
Enrollment
190
Start Date
2025-09-01
Completion Date
2027-03-03
Last Updated
2025-12-09
Healthy Volunteers
Yes
Interventions
Session A: Positive Placebo + Active tTIS
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.
Session B: Positive Placebo + Sham tTIS
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.
Session C: Negative Placebo + Active tTIS
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.
Session D: Negative Placebo + Sham tTIS
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.
Session E: On-Placebo + Sham tTIS
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.
Session F: Off-Placebo + Sham tTIS
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)
Dartmouth College, Department of Psychological and Brain Sciences
Hanover, New Hampshire, United States