Resting-state Connectivity and Individual Differences in Affective Placebo Responsiveness
试验速览
- 阶段
- 不适用
- 状态
- Enrolling By Invitation
- 发起方
- 入组人数
- 50
- 试验地点
- 1
- 主要终点
- Resting-state functional connectivity measures in prefrontal-emotion-related circuitry
研究概览
简要总结
Expectation effects on affective states are central to mechanisms relevant for mood disorders and their treatment. This study will test whether inter-individual differences in resting-state functional connectivity (rsFC) within emotion regulation networks is associated with affective placebo responsiveness in healthy volunteers. Approximately 50 healthy participants will be pooled from two cross-over placebo studies in which participants receive intranasal saline either labeled as "oxytocin" in the placebo condition or as saline in the control condition.
Primary indices of placebo responsiveness are placebo-control difference scores of mood state, emotional paradigm responses, as well as expectation and experience ratings.
rsFC will be estimated using the CONN toolbox. Confirmatory analyses will use an a priori seed-based approach, with prefrontal seeds derived from previous task-based fMRI findings on affective placebo effects. These analyses will be complemented by secondary summaries of within- and between-network connectivity across the saliency network, the fronto-parietal control network, and the default mode network.
We hypothesize that interindividual differences in target rsFC networks will be associated with affective placebo effects, indicating general, trait-like mechanisms of placebo responsiveness.
详细描述
Background Understanding the neurobiological mechanisms underlying expectation effects in the affective domain can provide important insights into therapeutic principles relevant to mood disorders.
Placebo and expectancy effects are substantial in mood-related interventions and can be elicited experimentally in healthy samples using standardized, instruction-based expectation inductions combined with sham treatment. In related experimental paradigms based on the same broader framework, experimentally induced positive expectations have been shown to enhance subjective mood and bias emotional information processing toward positivity even in the absence of an active pharmacological agent.
Recent work further emphasizes marked interindividual variability in these effects, suggesting that affective placebo effects are stronger when more cognitive resources are available and are accompanied by lateral prefrontal engagement together with stronger coupling in prefrontal-limbic networks.
This pattern motivates an individual-differences approach in which expectancy effects depend, at least in part, on the capacity to initiate and maintain instructed treatment beliefs and to translate them into downstream affective processing. Resting-state fMRI (rsfMRI) offers a well-established way to quantify intrinsic functional coupling among large-scale brain systems. Resting-state functional connectivity (rsFC) is commonly used to characterize individual-specific and partly trait-like components of functional network organization, while also encompassing state-dependent variance and measurement constraints.
Such individual differences in rsFC have been linked to variability in executive functioning and broader phenotypic differences across healthy and clinical populations.
研究设计
- 研究类型
- Observational
- 观察模型
- Cohort
- 时间视角
- Prospective
入排标准
- 年龄范围
- 18 Years 至 35 Years（Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Aged 18-35 years
- •MRI compatible
- •Medical information and signed declaration of consent
- •Normal or corrected to normal vision
- •German speaking
排除标准
- •No informed consent
- •Current intake of central nervous system active drugs
- •Under influence of alcohol
- •BDI score above 12
- •Significant acute somatic or neurological diseases
- •History of psychiatric or neurological disorders
- •Pregnancy/ breastfeeding
- •Acute nasal diseases or injuries
- •MR-specific exclusion criteria (claustrophobia, pacemaker, non-MR compatible metallic objects)
- •fMRI data with strong artefacts or excessive movement will be excluded from analysis
研究组 & 干预措施
Healthy volunteers
This rs-fMRI study will include healthy volunteers who completed an expectation-manipulation study and agreed to an additional rs-fMRI session.
The sample will be drawn from the ongoing ClinicalTrials.gov-registered study "Expectation Effects on Emotional Processing" (NCT07031804) (Szabo et al., in prep) and a previously collected cohort reported by Mostauli et al. (2025).
干预措施: No intervention (Other)
结局指标
主要结局
Resting-state functional connectivity measures in prefrontal-emotion-related circuitry
时间窗: During one separate post-paradigm MRI session lasting approximately 45 minutes, after completion of the preceding placebo study protocol.
Resting-state fMRI will be used to estimate Fisher r-to-z transformed functional connectivity using seed-based and ROI-to-ROI analyses within prefrontal-emotion-related circuitry. These rsFC measures will be tested for associations with participant-level placebo-response indices derived from prior placebo/control sessions.
次要结局
- Within-network and between-network resting-state functional connectivity across canonical large-scale networks(During one separate post-paradigm MRI session lasting approximately 45 minutes, after completion of the preceding placebo study protocol.)
研究者
Stefanie Brassen
Prof. Dr.
Universitätsklinikum Hamburg-Eppendorf