Age differences in spatial working memory contributions to visuomotor adaptation and transfer

Abstract

Throughout our life span we encounter challenges that require us to adapt to the demands of our changing environment; this entails learning new skills. Two primary components of motor skill learning are motor acquisition, the initial process of learning the skill, and motor transfer, when learning a new skill is benefitted by the overlap with a previously learned one. Older adults typically exhibit declines in motor acquisition compared to young adults, but remarkably, do not demonstrate deficits in motor transfer [10]. Our recent work demonstrates that a failure to engage spatial working memory (SWM) is associated with skill learning deficits in older adults [16]. Here, we investigate the role that SWM plays in both motor learning and transfer in young and older adults. Both age groups exhibited performance savings, or positive transfer, at transfer of learning for some performance variables. Measures of spatial working memory performance and reaction time correlated with both motor learning and transfer for young adults. Young adults recruited overlapping brain regions in prefrontal, premotor, parietal and occipital cortex for performance of a SWM and a visuomotor adaptation task, most notably during motor learning, replicating our prior findings [12]. Neural overlap between the SWM task and visuomotor adaptation for the older adults was limited to parietal cortex, with minimal changes from motor learning to transfer. Combined, these results suggest that age differences in engagement of cognitive strategies have a differential impact on motor learning and transfer.

Figure 1

Performance measures for the 30° visuomotor adaptation for both young (YA) and older (OA) adults. 3A. YA DE, 3B. OA DE, 3C. YA IEE, 3D. OA IEE, 3E. YA RT, 3F. OA RT.

Figure 2

Performance measures for the 45° visuomotor adaptation for both young (YA) and older (OA) adults. 4A. YA DE, 4B. OA DE, 4C. YA IEE, 4D. OA IEE, 4E. YA RT, 4F. OA RT.

Figure 3

Correlations between kinematic variables (DE and IEE) and verbal working memory (Reading Span Score) for older adults.

Figure 4

Areas exhibiting greater activation at motor learning than transfer (run 3>13). 4A. Young adults show greater activation in the right superior frontal gyrus, cingulate cortex and parietal lobe during motor learning compared to transfer (run 3>13). 4B. Older adults show greater activation in the right superior parietal lobe during motor learning compared to transfer (run 3>13).

Figure 5

Age differences in brain activation at initial motor learning. 5A. Areas in which young adults (YA) exhibit greater activation than older adults (OA) during motor learning (run 3). YA demonstrated greater activation in the left postcentral gyrus, right superior frontal gyrus and middle occipital lobule compared to OA. 5B. Areas in which older adults (OA) exhibit greater activation than young adults (YA) during motor learning (run 3). OA demonstrated greater activation in the right postcentral gyrus and paracentral lobule compared to YA.

Figure 6

Areas in which young adults (YA) exhibit more activation than older adults (OA) during transfer of learning (run 13). YA demonstrated greater activation in the left putamen, right caudate nucleus, and left cingulate gyrus compared to OA.