The Tap-To-Safety Task: A Novel fMRI Paradigm Assessing Repetitive Threat-Neutralization

IntroductionExisting experimental threat-related paradigms focus primarily on active or passive avoidance behavior, but do not model the common behavioral pattern of repetitive, effortful actions aimed at neutralizing perceived threats. Here, we describe and provide initial validation for the Tap-To-Safety Task, a novel human paradigm designed to experimentally elicit repetitive threat-neutralization behavior during functional magnetic resonance imaging (fMRI).MethodsAdult participants completed the Tap-To-Safety Task; one sample completed the task online and an additional sample completed the task in person, with a subsample completing fMRI. Task stimuli included a threat cue (CS+) paired with an aversive unconditioned stimulus (US), safety cues (CS-) never paired with the US, and safe generalization stimuli (GSs) varying in similarity to the CS+. During an extinction phase, the CS+ was no longer paired with the US. Trials included passive viewing trials, without a neutralization option; and choice trials, in which participants could tap a button repeatedly to gain protection from the US (i.e., repetitive threat-neutralization) while reducing accumulation of reward points. Linear mixed-effects models were used to assess behavioral and neural responses. For fMRI analyses in a subset of participants, a priori regions of interest (ROIs) were used with Bonferroni correction.ResultsBehavioral results (n=49) demonstrated increased threat expectancy, anxiety, and repetitive threat-neutralization behavior were higher to the threat cue than to safety cues (ps<.001, ηp2>.42), and generalized across safe stimuli resembling the threat-cue (ps<.001, ηp2>.42). During extinction, risk and anxiety ratings gradually decreased (ps<.015, ηp2>.01), whereas neutralization behavior persisted (p=.10). Greater trial-wise neutralization predicted lower post-neutralization threat-expectancy and anxiety ratings (ps<.005, ηp2>.11). Behavioral results were largely replicated in an online sample (n=89). Analyses of fMRI data (n=31) indicated that neural activity pre-neutralization in anterior insula, dorsal anterior cingulate cortex, and dorsal striatum scaled with threat-relevance of stimuli (ps<.001, ηp2 >.30) and with magnitude of neutralization (ps<.003, ηp2 >.06). ConclusionThese findings support the use of the Tap-To-Safety Task for quantifying the behavioral and neural mechanisms of repetitive threat-neutralization. Results point to a key role of the salience network and dorsal striatum. Future research in clinical populations is warranted.