Better later: evening practice is advantageous for motor skill consolidation in the elderly

Abstract

How does the time of day of a practice session affect learning of a new motor sequence in the elderly? Participants practiced a given finger tapping sequence either during morning or evening hours. All participants robustly improved performance speed within the session concurrent with a reorganization of the tapping pattern of the sequence. However, evening-trained participants showed additional gains overnight and at 1 wk posttraining; moreover, evening training led to a further reorganization of the tapping pattern offline. A learning experience preceding nocturnal sleep can lead to a task-specific movement routine as an expression of novel "how to" knowledge in the elderly.

Figure 1.

The time course and the learning gains in the Eve (blue) and Morn (orange) groups for within-sequence duration (A) and between-sequence transition (B). Group averages of all performance blocks (lines) and time points (markers) representing the mean of four performance blocks during the online (start to end) and offline (end to 24 h and 1 wk) learning phases are shown. (Insets) Gains in performance at 24-h and 1-wk retests relative to the end of training (percentage). Bars indicate standard error of the mean (S.E.M.). (**) P < 0.05.

Figure 2.

Changes in the tapping pattern (vector of four within-sequence transitions). Changes in the tapping pattern for two representative participants from Morn (A) and Eve (B) groups. Mean interkey transitions of the sequence (connected with thin colored lines) for each block during the online (training) and following the offline phases (24-h and 1-wk retests) are shown. The shape of each line illustrates a tapping pattern for a single block. The last training block is represented by thick dashed red line (the “seed” reference block) in all panels. Group averages of individual normalized Pearson correlation coefficients (bars) between tapping patterns at the end of practice (14-th block—black arrow) and each block during the practice (blocks 1–13) and 24-h and 1-wk retest are shown for Morn (C) and Eve (D) groups. (E) Differences in the changes of the tapping pattern between the groups. Mean correlation coefficients across the initial and final four blocks of the training session and each retest. Bars indicate standard error of the mean (S.E.M.). (*) 0.1 > P > 0.05, (**) P < 0.05.