Although fear conditioning is one of the most widely used models to study anxiety, some aspects of its neural correlates remain unexplored. It is known that the retrieval of consolidated memories can trigger modifications depending on the cues presented during the reminder. 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 triggered by the presentation of the CS+ alone, 24 hours after acquisition. We analyzed 90 seconds of resting-state electroencephalographic activity following the reminder cue, comparing two groups: a Reactivation group exposed to threat conditioning on the first day, and a Control group with no prior conditioning. A cluster-based permutation test revealed that the Reactivation group showed significantly lower beta-band activity (23–30 Hz) in central regions following the reminder. Then we conducted a deep analysis of the resting state using microstate analysis. Microstates, short quasi-stable topographies of brain activity that re-occur over time, have been proposed as blocks of information processing in the brain. We found significant differences between experimental groups (3-30 Hz), indicating distinct brain states across conditions. Our findings highlight the relevance of evaluating neural correlates of resting post-retrieval processes, including decreased beta activity related to implicit memory.