Аннотация:During the last decades, neural oscillations in the β-range (15-25 Hz) have grown out of the traditional role of a “sensorimotor idling” rhythm and have been associated with higher cognitive processes. The post-response β-event-related synchronization (β-ERS) was proposed to maintain and strengthen the currently activated cognitive representations of the associative rules, but the supported evidence in humans is scarce.Here, we sought to evaluate β-power dynamics accompanying the associative rule learning and practicing the same task after a night’s sleep and after repetition of training on the second day. We recorded magnetoencephalographic signals while 27 participants acquired in trial-and-error manner associations between acoustically presented pseudowords and hands/feet movements. We compared β-power for correct motor responses induced by pseudoword cues (1) at the very start of learning on the day1, (2) at the end of learning on the day1, (3) at the start of the day2 after a night’s sleep, and (4) at the end of the whole learning procedure on day2.Judging by the absence of errors in conditions (2)-(4), the correct pseudoword-movement associations were mastered during day 1 and the acquired rules were carried over to day 2. Neither reaction time nor error rate was improved after a night’s sleep. Behavioral learning was accompanied by the large-scale β-ERS over the associative cortical regions, which appeared only when the rules were learned at the end of day 1, and, without fading in strength after a night’s sleep, followed the errorless task performance and task repetition throughout day 2. In line with the suggested role of the prefrontal β-ERS in retaining the acquired rules, the β-ERS at the prefrontal cortex did not grow in strength during the repetitive training over day 2, whereas such progressive increase did characterize β-ERS originating from associative temporal and parietal cortical areas. Our results support the hypothetical role of the large-scale β-ERS in the strengthening of memory traces for associative rule learning in the human brain. A lack of the significant effect of a night’s sleep on behavioral and neural concomitants of the newly trained words suggests that a night’s sleep alone is not sufficient for consolidation to occur. It appears that other factors (e.g., the rule practicing over day 2) might also influence the transferring of newly learned association patterns from short-term to long-term memory.