Abstract ↔ claims

¹When we learn that something is dangerous, a fear memory is formed. ²However, this memory is not fixed and can be updated through new experiences, such as learning that the threat is no longer present. ³This process of updating, known as extinction or reversal learning, is highly dependent on the context in which it occurs. ⁴How the brain represents cues, contexts, and their changing threat value remains a major question. ⁵Here, we used functional magnetic resonance imaging and a novel fear learning paradigm to track the neural representations of stimuli across fear acquisition, reversal, and test phases. ⁶We found that initial fear learning creates generalized neural representations for all threatening cues in the brain’s fear network. ⁷During reversal learning, when threat contingencies switched for some of the cues, two distinct representational strategies were observed. ⁸On the one hand, we still identified generalized patterns for currently threatening cues, whereas on the other hand, we observed highly stable representations of individual cues (i.e. item-specific) that changed their valence, particularly in the precuneus and prefrontal cortex. ⁹Furthermore, we observed that the brain represents contexts more distinctly during reversal learning. ¹⁰Furthermore, additional exploratory analyses showed that the degree of this context specificity in the prefrontal cortex predicted the subsequent return of fear, providing a potential neural mechanism for fear renewal. ¹¹Our findings reveal that the brain uses a flexible combination of generalized and specific representations to adapt to a changing world, shedding new light on the mechanisms that support cognitive flexibility and the treatment of anxiety disorders via exposure therapy.