Not feeling it? The influence of proprioception on impulse regulation processes

Abstract

Accurate reaching movements can theoretically benefit from multisensory feedback. Both vision and proprioception should be useful when performing early online limb trajectory amendments (i.e., impulse regulation; see Elliott et al., 2010). However, the notion of impulse regulation was developed with limb trajectory perturbations (i.e., altered movement demands but unaltered proprioception: Grierson & Elliott, 2008, 2009). The current study aimed to test the roles of movement demands versus proprioception on impulse regulation processes. Participants displaced one of two visually-identical aluminum cubes (i.e., 505 g and 480 g) towards a visual target (30 cm amplitude). The heavier cube was covertly switched to the lighter cube on one third of the trials, altering movement demands, and eliciting impulse regulation processes. Furthermore, to perturb proprioception, between-trial muscle tendon vibration was employed (Goodman & Tremblay, 2017). Finally, visual feedback was available on 50% of trials in a randomized fashion, to alter reliance on proprioception. Results confirmed that online vision led to more accurate and precise endpoint distributions. However, no variables analyzed yielded an interaction involving vision, suggesting that the effects of tendon vibration and cube weight were stable across vision conditions. In contrast, the lighter cube weight yielded higher peak velocities but no significant differences in endpoint distributions (i.e., effective impulse regulation). Finally, although vibration led to shifts in the average endpoint position, no measures associated with online control yielded any effects of tendon vibration. Even if methodological differences from previous work should be investigated, impulse regulation appears to be predominantly based on visual feedback.

Acknowledgments: Natural Sciences and Engineering Research Council of Canada (NSERC), Canada Foundation for Innovation (CFI), Ontario Research Fund (ORF), University of Toronto (UofT).