Abstract
Improvements in motor sequence learning come about via goal-based learning of the sequence of visual stimuli and muscle-based learning of the sequence of movement responses. In young adults, consolidation of goal-based learning is observed after intervals of sleep but not following wake, whereas consolidation of muscle-based learning is greater following intervals with wake compared to sleep. While the benefit of sleep on motor sequence learning has been shown to decline with age, how sleep contributes to consolidation of goal-based vs. muscle-based learning in older adults (OA) has not been disentangled. We trained young (n = 62) and older (n = 50) adults on a motor sequence learning task and re-tested learning following 12 h intervals containing overnight sleep or daytime wake. To probe consolidation of goal-based learning of the sequence, half of the participants were re-tested in a configuration in which the stimulus sequence was the same but, due to a shift in stimulus-response mapping, the movement response sequence differed. To probe consolidation of muscle-based learning, the remaining participants were tested in a configuration in which the stimulus sequence was novel, but now the sequence of movements used for responding was unchanged. In young adults, there was a significant condition (goal-based vs. muscle-based learning) by interval (sleep vs. wake) interaction, F(1,58) = 6.58, p = 0.013: goal-based learning tended to be greater following sleep compared to wake, t(29) = 1.47, p = 0.072. Conversely, muscle-based learning was greater following wake than sleep, t(29) = 2.11, p = 0.021. Unlike young adults, this interaction was not significant in OA, F(1,46) = 0.04, p = 0.84, nor was there a main effect of interval, F(1,46) = 1.14, p = 0.29. Thus, OA do not preferentially consolidate sequence learning over wake or sleep.
Highlights
Aging is often marked by a reduction in sleep quality; sleep efficiency decreases as wake after sleep onset increases
In young adults (YA), memory improves more over an interval containing sleep than over an equivalent interval spent awake, reflecting memory consolidation processes which are enhanced by sleep
Performance on the motor sequence learning task improves by only 2% over sleep in individuals 60–80 years of age and this improvement does not differ from that observed following an equivalent interval spent awake
Summary
Aging is often marked by a reduction in sleep quality; sleep efficiency decreases as wake after sleep onset increases. Rapid eye movement (REM) sleep time is reduced in older age and slow wave sleep (SWS) is reduced to an even greater extent (e.g., Ohayon et al, 2004). Such sleep changes have been posited to underlie changes in memory in conjunction with healthy aging (Buckley and Schatzberg, 2005; Hornung et al, 2005). In a motor sequence learning task, a classic probe of the procedural learning system (Nissen and Bullemer, 1987), reaction time (RT) is reduced by about 18% following a 12-h interval with sleep whereas only 4% reductions are observed following a 12-h interval spent awake (Walker et al, 2002; Spencer et al, 2006). Performance on the motor sequence learning task improves by only 2% over sleep in individuals 60–80 years of age and this improvement does not differ from that observed following an equivalent interval spent awake
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
