Learning by observation requires an early sleep window

Abstract

Numerous studies have shown that sleep enhances memory for motor skills learned through practice. Motor skills can, however, also be learned through observation, a process possibly involving the mirror neuron system. We investigated whether motor skill enhancement through prior observation requires sleep to follow the observation, either immediately or after a delay, to consolidate the procedural memory. Sequence-specific fingertapping performance was tested in 64 healthy subjects in a balanced design. Electromyography verified absence of overt or subliminal hand muscle activations during observation. The results show that immediate sleep is necessary for the enhancement of a motor skill through prior observation. Immediate sleep improved the speed of subsequent performance by 22 ؎ 11% (mean ؎ SEM) (P ‫؍‬ 0.04) and reduced the error rate by 42 ؎ 19% (P ‫؍‬ 0.02). In contrast, no performance gains occurred if sleep was initiated more than 12 h after observation. A second study on 64 subjects ruled out explicit familiarity with the sequence or the spatiotemporal rhythm of the sequence to underlie performance improvements. The sleepdependent observational motor learning enhancement is at least similar to that previously reported for implicit and declarative memory. The apparent prerequisite of observing real movements indicates that subjects transfer experience obtained through observation of movements to subsequent self-initiated movements, in the absence of practice. Moreover, the consolidation of this transfer requires an early sleep window. These findings could improve learning new motor skills in athletes and children, but also in patients having to remaster skills following stroke or injury.circadian rhythms ͉ memory consolidation ͉ mirror neurons ͉ offline improvement

About Sleep's Role in Memory

“…However, convincing behavioral clues for a reorganization of skill representations during sleep come from investigations of sequence-finger tapping skills that show that sleep favors the emergence of an effector independent representation, i.e., sleep benefited pressing the sequence of target keys independent of whether the sequence was tapped with the right or left hand, whereas the sequenced tapping movements per se appeared to benefit also from a wake retention interval (218,1330). Additionally, sleep enhanced sequence-finger tapping performance when learning occurred by observation (1234) or motor imagery (274), a further hint towards qualitative changes in the skill representations induced by sleep.…”

Not quite there: skill consolidation in training by doing or observing

“…However, it is not clear whether the overnight gains reflected sleep-dependent delayed gains, as performance measurements immediately after the observation session were available only for a different group of participants; observation afforded before noon, and followed by hours in the wake condition (delayed sleep), did not result in overnight performance gains (Van Der Werf et al 2009). The Experiment 1 and the control experiment suggest that as in actual training on the FOS task (Fischer et al…”

“…However, it is not clear whether the overnight gains reflected sleep-dependent delayed gains, as performance measurements immediately after the observation session were available only for a different group of participants; observation afforded before noon, and followed by hours in the wake condition (delayed sleep), did not result in overnight performance gains (Van Der Werf et al 2009). The Experiment 1 and the control experiment suggest that as in actual training on the FOS task (Fischer et al 2002;Walker et al 2002;Korman et al 2003Korman et al , 2007, training by observation afforded many hours before a night's sleep effectively triggered the subsequent expression of sequence-specific delayed gains in the performance of a trained movement sequence.…”

“…A landmark study (Van Der Werf et al 2009) has shown that repeated observation of a finger (key press) movement sequence can result in significant sequence-specific performance gains if the observation training experience is closely followed by sleep. However, it is not clear whether the overnight gains reflected sleep-dependent delayed gains, as performance measurements immediately after the observation session were available only for a different group of participants; observation afforded before noon, and followed by hours in the wake condition (delayed sleep), did not result in overnight performance gains (Van Der Werf et al 2009).…”

Sleep, Memory & Brain Rhythms

“…28 Imagination-based mental practice of movements or observation of others can also lead to improvements after sleep. 29 All of this supports the idea that new skills can be built, gained, or incorporated into the proper brain sites by sleep, which appears to be performing an active and constructive role. Additionally, people may rearrange their knowledge after a session of sleep, as evidenced by their committing novel errors in a systematic fashion that demonstrates they have internalized a general concept rather than the precise details of a given set of pre-sleep events.…”