Neural Mechanisms of Interpersonal Expectations on Negative Affect

Overview

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.

Detailed description

The study employs a within-subject, crossover factorial design, consisting of two experiments.

Experiment 1

In Experiment 1, 36 participants ('patients') will complete all combinations of two independent variables-stimulation type (active vs. sham tTIS) and placebo manipulation (positive vs. negative placebo messaging)-resulting in four sessions:

* Session A: Positive Placebo + Active tTIS * Session B: Positive Placebo + Sham tTIS * Session C: Negative Placebo + Active tTIS * Session D: Negative Placebo + Sham tTIS

Participants complete three multimodal negative affect tasks (MNAT) before and after each stimulation session. Active tTIS delivers two signals at 2000 Hz and 2010 Hz, generating an 10 Hz interference beat targeted at the anterior/mid-cingulate cortex (aMCC) at 2 mA for 20 minutes. Sham tTIS uses same frequencies (2000 Hz and 2010 Hz), targeting the same region for only 80 seconds.

Sessions are administered in a counterbalanced order based on a Williams Balanced Latin Square to minimize order effects, with at least 48 hours between sessions. Participants thus serve as their own controls.

Experiment 2

Experiment 2 includes 160 participants divided into two groups: 120 'patients' and 40 'doctors'.

A within-subject crossover design is employed, focusing specifically on placebo manipulation effects. Patients complete two experimental sessions involving sham tTIS only:

* Session E: On-Placebo + Sham tTIS (with social placebo intervention) * Session F: Off-Placebo + Sham tTIS (without placebo intervention)

In both sessions, patients complete the same MNAT tasks before and after stimulation. Sham tTIS involves a brief 15-second stimulation followed by no current for the remainder of the session, preserving the illusion of active stimulation.

'Doctors' are trained to administer the sham stimulation and deliver the placebo manipulation. During placebo induction sessions, providers simulate a "personalization" procedure, adjusting sham parameters while covertly reducing pain stimulus intensity to enhance placebo effects. Providers also monitor patients' nonverbal behavior and reported affect, offering feedback to enhance engagement and perceived treatment quality.

Participants undergo MRI scanning, physiological monitoring, and behavioral assessments during Experiment 2. Multimodal physiological data-including ECG, respiration, skin conductance, photoplethysmography (PPG), and trans-radial electrical bioimpedance velocimetry (TRVE)-are collected using the BIOPAC 160 system.

Interventions

• Behavioral Session A: Positive Placebo + Active tTIS
  Participants receive active tTIS with two channels set at 2000 Hz and 2010 Hz, creating a 10 Hz interference beat targeting the anterior/mid-cingulate cortex (aMCC). Stimulation is delivered at 2 mA per channel 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.
• Behavioral Session B: Positive Placebo + Sham tTIS
  Participants receive sham tTIS (brief 80-second stimulation followed by no current) paired with a positive social placebo intervention. The device mimics active parameters (2 mA per channel, 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.
• Behavioral Session C: Negative Placebo + Active tTIS
  Participants receive active tTIS (2000 Hz and 2010 Hz signals, 2 mA per channel, 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.
• Behavioral Session D: Negative Placebo + Sham tTIS
  Participants receive sham tTIS (brief 80-second stimulation followed by no current) combined with a negative social placebo intervention. Participants complete three MNAT tasks before and after the session.
• Behavioral 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.
• Behavioral 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.

Primary outcome measures

• Cognitive effort ratings [Time frame: 3-10 sec post-stimulus throughout testing sessions, with all sessions complete within 1 month]
• Subjective fear ratings [Time frame: 3-10 sec post-stimulus throughout testing sessions, with all sessions complete within 1 month]
• Pain ratings [Time frame: 3-10 sec post-stimulus throughout testing sessions, with all sessions complete within 1 month]

Secondary outcome measures (1)

• Electrodermal autonomic responses to painful heat, fear-related images and cognitive effort [Time frame: Peri-stimulus throughout testing sessions, with all sessions complete within 1 month]

Eligibility criteria

Inclusion criteria

'Doctors' are recruited from medical students at the Geisel School of Medicine and resident physicians at Dartmouth Hitchcock Medical Center (DHMC).

Exclusion criteria

• 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)

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: Yes

Study design

Allocation

Randomized

Model

Crossover

Masking

Triple blind

Primary purpose

Basic science

Study locations

United States · 1 center

• Dartmouth College, Department of Psychological and Brain Sciences — Hanover

Publications

• Acerbo E, Jegou A, Luff C, Dzialecka P, Botzanowski B, Missey F, Ngom I, Lagarde S, Bartolomei F, Cassara A, Neufeld E, Jirsa V, Carron R, Grossman N, Williamson A. Focal non-invasive deep-brain stimulation with temporal interference for the suppression of epileptic biomarkers. Front Neurosci. 2022 Aug 17;16:945221. doi: 10.3389/fnins.2022.945221. eCollection 2022. PMID 36061593
• Wessel MJ, Beanato E, Popa T, Windel F, Vassiliadis P, Menoud P, Beliaeva V, Violante IR, Abderrahmane H, Dzialecka P, Park CH, Maceira-Elvira P, Morishita T, Cassara AM, Steiner M, Grossman N, Neufeld E, Hummel FC. Noninvasive theta-burst stimulation of the human striatum enhances striatal activity and motor skill learning. Nat Neurosci. 2023 Nov;26(11):2005-2016. doi: 10.1038/s41593-023-01457-7. PMID 37857774
• von Conta J, Kasten FH, Schellhorn K, Curcic-Blake B, Aleman A, Herrmann CS. Benchmarking the effects of transcranial temporal interference stimulation (tTIS) in humans. Cortex. 2022 Sep;154:299-310. doi: 10.1016/j.cortex.2022.05.017. Epub 2022 Jun 16. PMID 35839572
• Violante IR, Alania K, Cassara AM, Neufeld E, Acerbo E, Carron R, Williamson A, Kurtin DL, Rhodes E, Hampshire A, Kuster N, Boyden ES, Pascual-Leone A, Grossman N. Non-invasive temporal interference electrical stimulation of the human hippocampus. Nat Neurosci. 2023 Nov;26(11):1994-2004. doi: 10.1038/s41593-023-01456-8. Epub 2023 Oct 19. PMID 37857775
• Vassiliadis P, Beanato E, Popa T, Windel F, Morishita T, Neufeld E, Duque J, Derosiere G, Wessel MJ, Hummel FC. Non-invasive stimulation of the human striatum disrupts reinforcement learning of motor skills. Nat Hum Behav. 2024 Aug;8(8):1581-1598. doi: 10.1038/s41562-024-01901-z. Epub 2024 May 29. PMID 38811696
• Sandra DA, Olson JA, Langer EJ, Roy M. Presenting a sham treatment as personalised increases the placebo effect in a randomised controlled trial. Elife. 2023 Jul 5;12:e84691. doi: 10.7554/eLife.84691. PMID 37405829
• Grossman N, Bono D, Dedic N, Kodandaramaiah SB, Rudenko A, Suk HJ, Cassara AM, Neufeld E, Kuster N, Tsai LH, Pascual-Leone A, Boyden ES. Noninvasive Deep Brain Stimulation via Temporally Interfering Electric Fields. Cell. 2017 Jun 1;169(6):1029-1041.e16. doi: 10.1016/j.cell.2017.05.024. PMID 28575667

Identifiers

NCT: NCT06980090 · 467251

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗