Gradual Extinction via US Intensity Reduction: a Translational Test of Fear Memory Updating in Humans
Abstract
Relapse of fear-related symptoms after exposure-based treatment remains a major challenge across anxiety disorders. One potential explanation is that extinction learning yields a new memory trace rather than being integrated with the original fear memory, allowing fear to resurface. Building on recent research in rodents, we tested whether gradually reducing the intensity of the unconditioned stimulus (US) during extinction attenuates the return of fear in humans by promoting the integration of extinction learning into existing fear memories. Using a two-day fear-conditioning paradigm, 60 participants underwent differential fear acquisition, in which one stimulus (conditioned stimulus, CS+) was paired with an aversive electric stimulation (US), while another stimulus (CS−) was never paired. Participants were then randomly assigned to either classic extinction (CE), in which no US was delivered, or gradual extinction (GE), in which the US intensity was progressively reduced across blocks. On the second day, fear memory was assessed using spontaneous recovery and reinstatement tests. Subjective fear ratings and heart rate responses were comparable between extinction procedures. In contrast, during spontaneous recovery, electrodermal responses were larger in the CE group than in the GE group, with heightened responses to both CS+ and CS−. Overall, our findings provide partial support for the translation of gradual extinction effects observed in animal models to humans. While effects differed across response systems, the attenuated electrodermal recovery following gradual extinction suggests that progressively reducing US intensity to minimize prediction errors may alter the subsequent expression of fear memories. These findings highlight gradual US-intensity reduction as a promising translational approach for investigating mechanisms underlying fear relapse in humans.
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BibTeX
@misc{tortora2026gradual,
title = {{Gradual Extinction via US Intensity Reduction: a Translational Test of Fear Memory Updating in Humans}},
author = {Francesco Tortora and Ebru Ecem Tavacioglu and Yannik Stegmann and Marta Andreatta and Matthias Gamer},
howpublished = {PsyArXiv},
year = {2026},
month = oct,
doi = {10.31234/osf.io/qds25_v1},
url = {https://osf.io/preprints/psyarxiv/qds25_v1/},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Gradual Extinction via US Intensity Reduction: a Translational Test of Fear Memory Updating in Humans
AU - Francesco Tortora
AU - Ebru Ecem Tavacioglu
AU - Yannik Stegmann
AU - Marta Andreatta
AU - Matthias Gamer
PY - 2026
DA - 2026/10/20
PB - PsyArXiv
DO - 10.31234/osf.io/qds25_v1
UR - https://osf.io/preprints/psyarxiv/qds25_v1/
AB - Relapse of fear-related symptoms after exposure-based treatment remains a major challenge across anxiety disorders. One potential explanation is that extinction learning yields a new memory trace rather than being integrated with the original fear memory, allowing fear to resurface. Building on recent research in rodents, we tested whether gradually reducing the intensity of the unconditioned stimulus (US) during extinction attenuates the return of fear in humans by promoting the integration of extinction learning into existing fear memories. Using a two-day fear-conditioning paradigm, 60 participants underwent differential fear acquisition, in which one stimulus (conditioned stimulus, CS+) was paired with an aversive electric stimulation (US), while another stimulus (CS−) was never paired. Participants were then randomly assigned to either classic extinction (CE), in which no US was delivered, or gradual extinction (GE), in which the US intensity was progressively reduced across blocks. On the second day, fear memory was assessed using spontaneous recovery and reinstatement tests. Subjective fear ratings and heart rate responses were comparable between extinction procedures. In contrast, during spontaneous recovery, electrodermal responses were larger in the CE group than in the GE group, with heightened responses to both CS+ and CS−. Overall, our findings provide partial support for the translation of gradual extinction effects observed in animal models to humans. While effects differed across response systems, the attenuated electrodermal recovery following gradual extinction suggests that progressively reducing US intensity to minimize prediction errors may alter the subsequent expression of fear memories. These findings highlight gradual US-intensity reduction as a promising translational approach for investigating mechanisms underlying fear relapse in humans.
ER -