Consolidation alters motor sequence-specific distributed representations

TLDR

Functional MRI studies of sequential motor skill acquisition have shown learning‑related reorganizations of cortico‑striatal and cortico‑cerebellar systems with initial hippocampal involvement, yet the functional significance of these activity‑level changes and their relation to learning‑related plasticity remain unclear. The study aims to investigate local circuits that tune to sequence‑specific information in motor sequence learning. This was done by measuring multivariate distances between patterns evoked by consolidated versus newly acquired motor sequence production. Representations in dorsolateral striatum, prefrontal and secondary motor cortices are stronger for consolidated sequences, while hippocampus and dorsomedial striatum show reduced engagement, indicating distinct evolution of sequence‑specific motor representations during skill acquisition and consolidation.

Abstract

Functional magnetic resonance imaging (fMRI) studies investigating the acquisition of sequential motor skills in humans have revealed learning-related functional reorganizations of the cortico-striatal and cortico-cerebellar motor systems accompanied with an initial hippocampal contribution. Yet, the functional significance of these activity-level changes remains ambiguous as they convey the evolution of both sequence-specific knowledge and unspecific task ability. Moreover, these changes do not specifically assess the occurrence of learning-related plasticity. To address these issues, we investigated local circuits tuning to sequence-specific information using multivariate distances between patterns evoked by consolidated or newly acquired motor sequences production. The results reveal that representations in dorsolateral striatum, prefrontal and secondary motor cortices are greater when executing consolidated sequences than untrained ones. By contrast, sequence representations in the hippocampus and dorsomedial striatum becomes less engaged. Our findings show, for the first time in humans, that complementary sequence-specific motor representations evolve distinctively during critical phases of skill acquisition and consolidation.