Time's up: When is it too late to implement online limb-target regulation processes?


Elliott et al.'s (2010) multiple processes model has provided a framework for different stages of online visual feedback utilization. Tremblay and colleagues (2013; 2017) assessed visual feedback utilization processes using a target-jump a paradigm, to specifically evaluate limb-target regulation. While results have provided evidence for optimal limb-target regulation early during fast reaching movements (i.e., ~350 ms), they failed to replicate these results for slower movements (i.e., ~700 ms: Crainic et al., 2017). Collectively, these results could indicate that it may be a time to movement end (i.e., approx. 290 ms) that represents a critical criterion to utilize vision for limb-target regulation processes. As such, the current study further investigated limb-target regulation during slower movements (i.e., ~700ms), while a brief window of visual feedback was provided at 0.3 m/s and 0.7 m/s before and after peak velocity. The latter window occurred later than in Crainic et al. (2017) and less than 290 ms before movement end. During the windows, participants either viewed the original target (30 cm) or a target closer to the start position (i.e., 27 cm: target jump). Endpoint accuracy data indicated that participants could use the window of vision to correct for the target jump in all but the last window condition. These results provide further evidence that time from movement end (e.g., Beggs & Howarth, 1972) could better explain visual feedback utilization strategies, than limb velocity (e.g., Tremblay et al., 2013) or other kinematic criterions (e.g., Elliott et al., 2010).

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