Abstract
Previous studies have provided consistent evidence that adaptation to visuomotor rotations during reaching declines with age. Since it has been recently shown that learning and retention components of motor adaptation are differentially modulated by reward and punishment, we were interested in whether age-related decline in reaching adaptation is modulated by motivational feedback. We studied 19 young (M=26.3 years, range 22–36 years) and 18 senior (M=68.2 years, range 60–76 years) adults in a reaching task, which required fast shooting movements towards visual targets with their right hand. Targets and visual feedback of hand position were presented on a mirror which prevented direct vision of the hand. A robotic manipulandum allowed measuring hand position. After a baseline with veridical visual feedback we introduced a 30° counterclockwise visuomotor rotation. After this adaptation phase we also measured retention of adaptation without visual feedback. Participants were randomly assigned to one of three value conditions in which performance was coupled to neutral feedback, monetary gain, or monetary loss. Corroborating previous results, senior adults showed a slower learning rate and a lower overall magnitude of adaptation than young adults (learning rate 0.06 vs. 0.20; directional change 17.9° vs. 26.0°). Retention, however, was found to be similar in both age groups. Motivational feedback had highly age-specific effects. Whereas in young adults adaptation was not modulated by value condition, magnitude of adaptation was larger in senior adults for reward and punishment conditions (directional change: 14.6° neutral, 20.8° reward, 18.5° punishment). Retention was affected by value condition in neither age group. Our results support that in particular senior adults benefit from motivational feedback during reaching adaptation and that age-related decline in visuomotor plasticity can be attenuated by providing value information.
Meeting abstract presented at VSS 2017