A longitudinal naturalistic fMRI study of trait anxiety and cross-phase consistency in subjective fear signature expression

Persistent fear is a central feature of anxiety, but it remains unclear whether this persistence is more closely related to the consistency of conditioned-threat processing or to the consistency of subjectively experienced fear. Using a longitudinal naturalistic viewing fMRI paradigm, we examined whether trait anxiety was associated with cross-phase consistency in the expression of two validated fear-related neural signatures. Forty-two participants completed two fMRI phases separated by approximately three months, viewing the same 18 naturalistic videos followed by a resting-state segment, resulting in 19 analysis segments for cross-phase analyses. We applied two pre-trained signatures of subjective fear and threat conditioning, independently developed by separate research groups, to estimate their expression over time and examined how consistently each signature was reexpressed across phases within participants. We found that higher trait anxiety was significantly associated with greater cross-phase consistency in subjective-fear signature expression, with a significantly stronger association than for threat-conditioning signature expression. The anxiety-consistency association was also stronger for the subjective-fear signature than for a general negative-affect signature. This association became more prominent over longer temporal windows and was not detected in the average time series of the amygdala, ventromedial prefrontal cortex, insula, or hippocampus. These findings suggest that individual differences in trait anxiety are associated with the consistent cross-phase reexpression of distributed neural patterns related to subjective fear. Taken together, this study demonstrates how predictive brain models combined with longitudinal naturalistic viewing can provide a new approach for examining individual differences in trait anxiety across repeated experiences of the same naturalistic contexts.