Multi-day Adaptation and Savings in Manual and Locomotor Tasks

ABSTRACT

Using an individual differences approach, we evaluated whether manual and locomotor adaptation are associated in terms of adaptation and savings across days, and whether they rely on shared underlying mechanisms involving visuospatial working memory or visual field dependence. Participants performed a manual and a locomotor adaptation task during 4 separate test sessions over a 3-month period. Reliable adaptation and savings were observed for both tasks. It was further found that higher visuospatial working memory performance and lower visual field dependence scores were associated with faster learning in the manual and locomotor tasks, respectively. Moreover, adaptation rates were correlated between the 2 tasks in the final test session, suggesting that people may gradually be learning something generalizable about the adaptation process.

Keywords:

• motor learning
• savings
• sensorimotor adaptation
• visuospatial abilities

FUNDING

This work was supported by the National Aeronautics and Space Administration (NASA; grant number NNX11AR02G), and in part by grants from the National Space Biomedical Research Institute through NASA NCC 9–58 (SA03801 and SA02801).

Notes

1. The present study was part of a larger study protocol aimed at evaluating the effects of spaceflight and a microgravity analogue on neurocognitive performance (Koppelmans et al., 2013; see also Cassady et al., 2016; Koppelmans et al., 2015; Yuan et al., 2016). Please note that all data reported here concern healthy control subjects only.

2. We considered using CT on the first trial as a measure of early adaptation in the locomotor task, but found no differential results using this approach. We therefore only report adaptation rate across the 10 trials that participants performed as a general measure of adaptation, and do not distinguish between early and late phases of locomotor adaptation.

3. As visual inspection of Figures 3B and 3C suggested that the presented relationship could potentially be driven by extreme data points, we tested the data for outliers. Grubbs’ test indicated that the lower-right data point in Figure 3B was an outlier. We therefore excluded this data point and reran the linear regression analysis. Results showed that the predictive value of cube rotation score on early manual adaptation rate remained significant when removing the outlier, β = −.682, t = −3.092 (df = 11), p = .010 (R² = .450). No outliers were detected for the data presented in Figure 3C.