Initial Implicit Changes in Adaptation as a Function of Different Perturbations

Abstract

Implicit motor adaptation allows us to maintain accurate movements under changing conditions. This process, driven by sensory prediction errors (SPE), mismatches between predicted and observed sensory-motor outcomes, corrects motor commands unconsciously. This study examined the extent to which initial implicit adaptation is sensitive to error magnitude and whether it reflects the behaviour observed in prolonged exposure contexts. We employed a single-trial learning (STL) paradigm within a classical visuomotor adaptation task. Participants reached to dot and arc targets while experiencing single rotated-cursor trials (1°-90°), isolating trial-by-trial changes in motor outputs, along with a long-exposure block involving a 20° rotation to test STL predictability in prolonged contexts. Results suggest initial implicit adaptation follows a saturating response pattern with increasing error magnitude while model-derived predictions tracked reasonably with long-exposure performance. Our findings reveal key features of early implicit adaptation and highlight STL as a promising tool for examining implicit adaptation in varying contexts.