Pavlovian threat conditioning retrospectively modulates episodic memory structured by pre-existing knowledge of predictive relations

Big Thanks to my collaborators and colleagues at the Department of Neurology @MPI-CBS.

Concept

Imagine an individual visiting a neighbour who hears a kennel gate open and sees a dog. Later, while inside the house, the dog becomes aggressive and injures the person. Cognitive psychology teaches us that the place where the aversive incident happened is likely to be well remembered in our long-term episodic memory, because it can warn us about the future face-to-face encounter with the dangerous dog. Likewise, seeing the dog again mobilises our defensive system to cope with the anticipated harm, which is elegantly described by first-hand Pavlovian threat conditioning — a fundamental mechanisms of associative learning for recognising threats. But what about the kennel gate outside the house? For example, the sound it makes when opening?

This project has shown that cues, such as the specific sound of the gate in our hypothetical scenario, may become also memorable. These inconspicuous cues can be prioritised in long-term episodic memory when they are retrospectively inferred to be of significance in predicting future threats. To support such inference, individuals can employ their pre-existing knowledge of environmental structure (e.g., a kennel gate is typically associated with a dog). In other words, recognizing stable environmental patterns may help retrospectively connect events encoded in separate learning episodes and contexts to aid inference about danger. Importantly, this mechanism allows us to identify signals that indicate the risk of harm before the threat is actually present.

Abstract

Individuals can infer danger by linking memories of relationships among neutral cues with later aversive experiences. However, it remains unclear how seemingly inconsequential events during encoding gain relevance for predicting future threats. Here, we tested whether Pavlovian threat conditioning retrospectively influences the long-term episodic memory of neutral events by leveraging pre-existing knowledge of their predictive relations. Young healthy adults (N=34) first learned that six semantic categories appeared in two deterministic sequences (ABC and DEF) and then incidentally encoded images of their trial-unique exemplars. Next, two sequence-ending categories (C vs. F) became differentially predictive of mild electric shocks. After 24 hours, recognition memory for pre-conditioned categories depended on sequence and position – when a sequence included a shock-predictive category, memory for its starting category (A) was prioritized at the expense of the successive category (B). These results suggest that aversive learning may retrospectively reshape episodic memories, adaptively fostering early threat anticipation.

TO BE RELEASED SOON – STAY TUNED

Acknowledgment

This work was supported by the Max Planck Society. BMB was supported by the Max Planck Society, the International Max Planck Research School “NeuroCom”, and the University of Leipzig.

License

This work is licensed under CC BY 4.0.