# Sequence-specific delayed gains in motor fluency evolve after movement observation training in the absence of early sleep

## TL;DR

Observing a motor sequence repeatedly leads to improved performance after a delay, even without sleep, similar to perceptual learning.

## Contribution

Demonstrates that delayed motor fluency gains after observation training occur without sleep, unlike physical practice.

## Key findings

- Immediate observation of a motor sequence does not improve performance compared to unobserved sequences.
- Delayed gains in performance for the observed sequence emerge 12 hours post-training, regardless of sleep.
- The largest performance improvements occur 24 hours after observation training.

## Abstract

Following physical practice, delayed, consolidation-phase, gains in the performance of the trained finger-to-thumb opposition sequence (FOS) can be expressed, in young adults, only after a sleep interval is afforded. These delayed gains are order-of-movements specific. However, in several perceptual learning tasks, time post-learning, rather than an interval of sleep, may suffice for the expression of delayed performance gains. Here we tested whether the affordance of a sleep interval is necessary for the expression of delayed performance gains after FOS training by repeated observation. Participants were trained by observing videos displaying a left hand repeatedly performing a 5-element FOS. To assess post-session observation-related learning and delayed gains participants were tested in performing the observed (trained) and an unobserved (new, the 5-elements mirror-reversed) FOS sequences. Repeated observation of a FOS conferred no advantage to its performance, compared to the unobserved FOS, immediately after practice. However, a clear advantage for the observed FOS emerged by 12 h post-training, irrespective of whether this interval included sleep or not; the largest gains appeared by 24 h post-training. These results indicate that time-dependent, offline consolidation processes take place after observation training even in the absence of sleep; akin to perceptual learning rather than physical FOS practice.