title: Multiple shifts in the representation of a motor sequence during the acquisition of skilled performance.
abstract: When do learning-related changes in performance occur? Here we show that the knowledge of a sequence of movements evolves through several distinctive phases that depend on two critical factors: the amount of practice as well as the passage of time. Our results show the following. (i) Within a given session, large performance gains constituted a signature for motor novelty. Such gains occurred only for newly introduced conditions irrespective of the absolute level of performance. (ii) A single training session resulted in both immediate but also time-dependent, latent learning hours after the termination of practice. Time in sleep determined the time of expression of these delayed gains. Moreover, the delayed gains were sequence-specific, indicating a qualitative change in the representation of the task within 24 h posttraining. (iii) Prolonged training resulted in additional between-session gains that, unlike the effects of a single training session, were confined to the trained hand. Thus, the effects of multisession training were qualitatively different than the immediate and time-dependent effects of a single session. Altogether, our results indicate multiple time-dependent shifts in the representation of motor experience during the acquisition of skilled performance.
authors.affiliation: Department of Neurobiology, Brain Research, The Weizmann Institute of Science, Rehovot 76100, Israel. maria.korman@weizmann.ac.il
authors.forename: Maria
authors.initials: M
authors.lastname: Korman
authors.forename: Naftali
authors.initials: N
authors.lastname: Raz
authors.forename: Tamar
authors.initials: T
authors.lastname: Flash
authors.forename: Avi
authors.initials: A
authors.lastname: Karni
mesh_terms: D000293:Adolescent; D000328:Adult; D001921:Brain / Q000502:physiology; D006801:Humans; D007858:Learning / Q000502:physiology*; D008568:Memory / Q000502:physiology; D009048:Motor Skills / Q000502:physiology*; D013997:Time Factors