The effect of age and perturbation time on online control during rapid pointing

Abstract

Visual and proprioceptive information is used differently at different phases of a reach. The time at which a target perturbation occurs during a reach therefore has a significant impact on how an individual can compensate for this perturbation though online control. With healthy ageing, there are notable changes to both sensory and motor control that impact motor performance. However, how the online control process changes with age is not yet fully understood. We used a target perturbation paradigm and manipulated the time at which a target perturbation occurred during the reach to investigate how healthy ageing impacts sensorimotor control. We measured how the latency of the correction and the magnitude of the corrective response changed with perturbation time and quantified the difference across groups using a percentage difference measure. For both groups, online corrections to early perturbations were more easily accounted for than those to late perturbations, despite late perturbations eliciting faster correction latencies. While there was no group difference in accuracy, older participants were slower overall and produced a correction to a change in target location proportionally less often despite similar correction latencies. We speculate that the differences in the time during the reach that the correction is first identified may explain the differences in correction latencies observed between the perturbation time conditions.

Age-related deficits in rapid visuomotor decision-making

“…Online feedback control is facilitated by dorsal stream areas in the posterior parietal cortex (Day and Lyon, 2000;Pisella et al, 2000). Not surprisingly, reaching studies using the target-jump paradigm have shown deficits in online feedback control in older adults (O'Rielly and Ma-Wyatt, 2019;Sarlegna, 2006). We only measured one aspect of kinematic performance, hand peak speed (PS), and found no differences between the groups or between conditions.…”

Saccade dynamics during an online updating task change with healthy aging

“…Data from a single younger exemplar depicting a left and right perturbation trial is presented. Adapted from O'Rielly and Ma-Wyatt (2019) .…”

“…As this overall process resulted in a disproportionate number of trials being removed across participants, participant mean scores across conditions (i.e., no perturbation, 0 ms left/0 ms right and 200 ms left/200 ms right) were used for analysis of dependent variables. Other analyses of the hand movement data have been published elsewhere ( O'Rielly & Ma-Wyatt, 2019 ). 1…”

“…Touch accuracy was calculated as the Euclidian distance (absolute value) in degrees of visual angle between the touch location and the final target location. The correction response to a target perturbation was determined in line with Song and Nakayama (2007) and Rossit and Harvey (2008) and as described in detail within O'Rielly and Ma-Wyatt (2019) . This process is briefly described in Figure 1 b.…”