Expectation Effects on Emotional Processing

Condition(s) studied

Investigational drug(s) / intervention(s)

Saline Nasal Spray: A saline nasal spray will be introduced as saline on the first day (no induced expectations) and as oxytocin on the second day (induced positive expectations)

Saline Nasal Spray: A saline nasal spray will be introduced as oxytocin on the first day (induced positive expectations) and as saline on the second day (no induced positive expectations)

Study summary

Understanding the mechanisms underlying expectation effects in the affective domain can provide valuable insights into possible therapeutic interventions for mood disorders. Studies have consistently found that expectations can influence emotional experiences. Recently, it has been shown that top-down cognitive control is critical in inducing instruction-based affective placebo effects. However, changes in the emotional system over time not only rely on higher-level cognitive processes but also on more automatic mechanisms shaped by learning and past experiences. How such mechanisms are involved in affective placebo effects is relatively unknown, but is particularly interesting in light of findings showing that previous experiences of successful treatments are an important determinant of placebo responses.

This study aims to investigate the neurobehavioral mechanisms of how expectations and prior experiences modulate emotional processing. Healthy adults (N = 51, 50% women) will be recruited to participate in a cross-over fMRI study involving two conditions: positive expectation induction (placebo) and a control condition with no induced expectations. Participants will perform an emotion classification task under each condition. The investigators hypothesize that positive expectations enhance mood and improve the accuracy of recognizing happy facial expressions. Further, they hypothesize that affective expectations are represented in fMRI signal patterns in networks involved in face perception, emotional processing, and cognitive control.

Eligibility

Primary outcome measure(s)

• Effects of positive expectation on mood — On both day 1 and day 2, measurements will be taken before the intervention (VAS baseline), 5 minutes after nasal spray application, and after the scanning (~ 60 minutes after nasal spray application).
  Mood ratings via visual analogue scale (VAS), consisting of a scale from 0 to 200 points (0 meaning unhappy; 200 meaning happy). VAS will be extracted as a raw score and then normalized to the baseline VAS. It will be analyzed to assess differences between interventions (placebo and control) and to evaluate changes over time throughout the experiment.
• Effects of positive expectation on task performance data — Approximately 15 minutes after the nasal spray application, participants will perform an emotion classification task for 40 minutes while lying in the scanner on each day.
  Accuracies from the emotion classification task will be extracted and sampled for 3 emotional (happy, fearful and neutral) conditions for both interventions (Placebo and Control). Performance during the placebo condition will be regressed onto performance during the control condition for each emotion. The resulting emotion-specific psychometric response functions will allow us to disentangle expectation effects with respect to response tendencies (the intercept) and discrimination ability (the slope).
• Effects of positive expectation on blood oxygen level dependent (BOLD) signals — Approximately 15 minutes after the nasal spray application, participants will lie in the scanner for ~ 40 minutes while performing the emotion classification task on each day.
  Functional magnetic resonance imaging will be used to extract and analyze BOLD signals (regions of interest and whole brain) in response to the emotional conditions and interventions. Univariate and multivariate analyses will be performed to compare activation profiles and the similarity of fMRI patterns during placebo and control.

Trial sites (1)

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