Biology subjects

Strueder, H. K.

Publications and source records attributed to Strueder, H. K..

3 recordsLinked to original sources

bioRxiv2022

Effect of repeated explicit instructions on visuomotor adaptation and intermanual transfer

The aim of the present study was to investigate the effect of repeated explicit instructions on visuomotor adaptation, awareness, and intermanual transfer. In a comprehensive study design, 48 participants performed center-out reaching movements before and during exposure to a 60{degrees} rotation of visual feedback. Awareness and intermanual transfer were then determined. Twelve participants each were assigned to one of the following adaptation conditions: gradual adaptation, sudden adaptation without instructions, sudden adaptation with a single instruction before adaptation, and sudden adaptation with multiple instructions before and during adaptation. The explicit instructions explained the nature of the visual feedback perturbation and were given using an illustration of a clock face. Analysis of adaptation indices revealed neither increased nor decreased adaptation after repeated instructions compared with a single instruction. Our data also show less adaptation with gradual than with sudden adaptation and less adaptation without than with instruction. These differences were pronounced at the beginning of adaptation; however, by the end of adaptation, all four groups reached similar levels of adaptation. In addition, we found significant group differences for the awareness index, with lower awareness after gradual adaptation than after sudden, instructed adaptation. Intermanual transfer did not differ between groups. However, we found a significant correlation between the awareness and intermanual transfer indices. We conclude that the magnitude of the explicit process cannot be further increased by repeated instruction and that intermanual transfer appears to be largely related to the explicit adaptation process.

neuroscience↗

bioRxiv2020

Martial arts training is related to implicit intermanual transfer of visuomotor adaptation

Recent work identified an explicit and implicit transfer of motor learning with one limb to the other untrained limb. Here we pursue the idea that different individual factors differently contribute to the amount of explicit and implicit intermanual transfer of sensorimotor adaptation. In particular we tested a group of judo athletes who show enhanced right-hemispheric involvement in motor control and a group of equally trained athletes as control participants. After adaptation to a 60{degrees} visual rotation, we estimated awareness of the perturbation and transfer to the untrained, non-dominant left hand in two experiments. We measured the total amount of intermanual transfer (explicit plus implicit) by telling the participants to repeat what was learned during adaptation and the amount of implicit transfer by instructing the participants to refrain from using what was learned but to perform movements as during baseline. We found no difference between the total intermanual transfer of judokas and running experts, with mean absolute transfer values of 42.4{degrees} and 47.0{degrees}. Implicit intermanual transfer was very limited but larger in judo than in general sports athletes, with mean values of 5.2{degrees} and 1.6{degrees}. A multiple linear regression analysis further revealed that total intermanual transfer, which largely represents the explicit transfer, is related to awareness of the perturbation while implicit intermanual transfer can be predicted by judo training, amount of total training, speed of adaptation and handedness scores. The findings are discussed in relation to neuronal mechanisms such as hemispheric interactions and functional specialization underlying intermanual transfer of motor learning.

neuroscience↗

bioRxiv2019

Intermanual transfer of visuomotor adaptation is related to awareness

Previous studies compared the effects of gradual and sudden adaptation on intermanual transfer to find out whether transfer depends on awareness of the perturbation. Results from different groups were contradictory. Since results of our own study suggest that awareness depends on perturbation size, we hypothesize that awareness-related intermanual transfer will only appear after adaptation to a large, sudden perturbation but not after adaptation to a small sudden perturbation or a gradual perturbation, large or small. To confirm this, four groups (S30, G30, S75, G75) of subjects performed out-and-back reaching movements with their right arm. In a baseline block, they received veridical visual feedback of hand position. In the subsequent adaptation block, feedback was rotated by 30 deg (S30, G30) or 75 deg (S75, G75). This rotation was either introduced suddenly (S30, S75) or gradually in steps of 3 deg (G30, G75). After the adaptation block, subjects did an awareness test comprising exclusion and inclusion conditions. The experiment concluded with an intermanual transfer block, in which movements were performed with the left arm under rotated feedback, and a washout block again under veridical feedback. We used a hierarchical Bayesian model to estimate individual movement directions and group averages. The movement directions in different conditions were then used to calculate group and individual indexes of adaptation, awareness, unawareness, transfer and washout. Both awareness and transfer were larger in S75 than in other groups, while unawareness and washout were smaller in S75 than in other groups. Furthermore, the size of awareness indices correlated to intermanual transfer across subjects, even when transfer was normalized to final adaptation level. Thus, we show for the first time that the amount of intermanual transfer directly relates to the extent of awareness of the learned perturbation.

neuroscience↗