The Influence of Midday Nap and Night-Time Sleep on Offline Consolidation of Action Sequences Learning

Offline consolidation refers to performance changes that occur after initial learning in the absence of further practice. Although sleep has often been associated with offline consolidation of sequence learning, it remains unclear whether different types of sleep contribute differently when compared with wakefulness and whether such effects depend on sequence characteristics. To address this issue, the present study employed a modified sequence reaction time task to examine offline changes in learned action sequences. Participants were assigned to one of four groups: night-time sleep, midday nap, daytime wake, or midday wake. Two sequence conditions differing in sequence length (short vs. long) were included to assess whether offline effects vary as a function of sequence length. We found that for long sequences, the night-time sleep group showed a larger offline consolidation effect than the midday nap group. In contrast, no reliable group differences were observed for short sequences. For both sequence conditions, the sleep groups differed from their respective wake control groups. Overall, these findings indicate that offline changes in action sequence learning are modulated by sequence length and differ across sleep-wake conditions.