AUTONOMIC AROUSAL MEDIATES THE RELATIONSHIP BETWEEN DISTRIBUTED NEURAL THREAT APPRAISAL AND SUBJECTIVE EMOTIONAL EXPERIENCE

Threat appraisal relies on coordinated neural and physiological processes that transform sensory information into autonomic and subjective fear responses. However, how large-scale brain activity relates to peripheral arousal and conscious experience during threat learning remains unclear. We developed a whole-brain multivariate fMRI signature of visually induced threat appraisal using support vector machine classification of conditioned threat (CS+) versus safety (CS−) cues during fear conditioning in a non-clinical sample characterized by dimensional variability in anxiety (N=172). The resulting signature reliably discriminated threat from safety with high cross-validated accuracy, generalized across learning phases and independent participants, and showed stable anatomical contributions spanning salience, limbic, and regulatory systems. Pattern expression values—reflecting the degree to which the threat-related neural pattern was expressed in each individual’s CS+ contrast image—were computed for each participant and used in subsequent physiological analyses.To examine brain–psychophysiological relationships, we tested whether autonomic arousal mediated associations between neural threat responses and subjective experience. Skin conductance responses (SCRs) fully mediated the association between threat-related pattern expression and subjective arousal (total effect: t=2.89, p=0.007; indirect effect: t=2.55, p=0.004), and partially mediated associations with subjective valence (total effect: t=3.20, p=0.001; indirect effect: t=2.51, p=0.002). Higher neural threat expression predicted greater autonomic responses, which in turn predicted more intense subjective threat experience.
These findings identify autonomic arousal as a key physiological mechanism linking distributed neural representations of threat appraisal to subjective experience and could provide a mechanistic framework for understanding individual variability in anxiety-related phenotypes.