Description

This study examines how belief-driven expectations modulate empathic pain at both behavioral and neural levels. Healthy adult participants will be randomly assigned to one of three groups: no-treatment control, placebo nasal spray, oxytocin-containing nasal spray. Participants in both the placebo and oxytocin conditions will be informed that they are receiving oxytocin, described as a potent agent for pain relief.

During fMRI scanning, participants will complete a naturalistic empathic pain task by viewing videos depicting others in pain and rating their perceived pain on a standardized scale. Behavioral data will be transformed into analgesia-weighted scores to capture individual sensitivity to expectation-driven analgesia. Neural data will include whole-brain voxel-wise activity, multivariate predictive patterns derived from partial least squares regression (PLSR), and directed functional connectivity assessed using lagged partial-correlation directionality analysis (LPC-DA) to evaluate top-down and bottom-up information flow.

The primary objectives are to (1) assess the behavioral effects of expectation-driven analgesia, (2) identify brain regions predictive of pain modulation, and (3) characterize hierarchical network reorganization under different interventions.