Neural correlates of aversive memory extinction: A time-frequency EEG study of post-retrieval processes

Although fear conditioning is widely used to study anxiety, some aspects of its neural correlates remain unexplored. Reactivating consolidated memories can trigger different modifications depending on the cues presented during reactivation. We employed a three-day threat conditioning protocol in which an angry face (CS+) was paired with an aversive sound (US). Our main objective was to identify neural markers of post-retrieval processes, particularly extinction, triggered by presenting the CS+ six times without the US, 24 hours after acquisition. At the behavioral level, extinction reduced declarative US expectancy and eliminated the cognitive bias in perceived aversiveness. We analyzed 90 seconds of resting-state electroencephalographic activity before and after each reminder cue. A cluster-based permutation test revealed differences between the first and last reminder presentations, with higher beta activity (23–30 Hz) during the last presentation. This is consistent with a previous finding in which lower beta activity was associated with memory reactivation, whereas higher activity was associated with a cue without prior information. Thus, after extinction, brain activity became more similar to that elicited by a non-informative stimulus. Our findings highlight the importance of evaluating neural correlates of post-retrieval processes and suggest that beta activity may relate to implicit memory reactivation and extinction.