Figure 1. Study design. In the afternoon group, 25 subjects were trained at 3 pm, followed by standardized activities (e.g., card games, movies).

In the evening group, 25 subjects were trained at 9 pm. The experimental sleep-laboratory night (10:30 pm to 7:30 am) followed a first adaptation night in the sleep laboratory. Parameters of memory consolidation were assessed across retention intervals of 24 hours and 7 days.