Individual movement features during prism adaptation correlate with after-effects and interlimb transfer

Abstract

The human nervous system displays such plasticity that we can adapt our motor behavior to various changes in environmental or body properties. However, how sensorimotor adaptation generalizes to new situations and new effectors, and which factors influence the underlying mechanisms, remains unclear. Here we tested the general hypothesis that differences across participants can be exploited to uncover what drives interlimb transfer. Twenty healthy adults adapted to prismatic glasses while reaching to visual targets with their dominant arm. Classic adaptation and generalization across movement directions were observed but transfer to the non-dominant arm was not significant and inter-individual differences were substantial. Interlimb transfer resulted for some participants in a directional shift of non-dominant arm movements that was consistent with an encoding of visuomotor adaptation in extrinsic coordinates. For some other participants, transfer was consistent with an intrinsic coordinate system. Simple and multiple regression analyses showed that a few kinematic parameters such as peak acceleration (or peak velocity) and variability of movement direction were correlated with interlimb transfer. Low peak acceleration and low variability were related to extrinsic transfer while high peak acceleration and high variability were related to intrinsic transfer. Motor variability was also positively correlated with the magnitude of the after-effect systematically observed on the dominant arm. Overall, these findings on unconstrained movements support the idea that individual movement features could be linked to the sensorimotor adaptation and its generalization. The study also suggests that distinct movement characteristics may be related to different coordinate frames of action representations in the nervous system.

Interlimb Transfer of Reach Adaptation Does Not Require an Intact Corpus Callosum: Evidence from Patients with Callosal Lesions and Agenesis

“…Across controls and patients, we did observe two profiles of interlimb transfer to the non-dominant arm: the majority with initial leftward deviation (opposite to the prismatic perturbation), consistent with encoding in extrinsic coordinates, and a few participants with initial rightward deviation (in the same direction as the prismatic perturbation), consistent with encoding in intrinsic coordinates. Overall, these findings support and extend those found on young, healthy individuals (Kalil and Freedman, 1966;Renault et al, 2020).…”

“…To assess sensorimotor adaptation and interlimb transfer, we employed a procedure inspired by previous work (Dizio and Lackner, 1995;Harris, 1963;Kitazawa et al, 1997;Lefumat et al, 2015;Martin et al, 1996a) and recently used by Renault et al (2020). The experimental session consisted of 3 phases (presented in Figure 2): a baseline pre-exposure phase under normal vision (baseline phase), a prism exposure phase with prismatic perturbation (prism phase) and a postexposure phase under normal vision (post phase).…”

“…During this post phase, the first target presented (post 1 trial) was always the middle straight-ahead 0° target, before all remaining targets were presented in a randomised fashion. The order of experimental phases was selected, as in previous studies (Lefumat et al, 2015;Renault et al, 2020), to have the non-dominant arm baseline and post-phases immediately before and after the dominant arm prism adaptation phase. Any difference in non-dominant arm performance could thus be directly attributed to dominant arm prism adaptation, thus showing interlimb transfer.…”

Perception of body shape and size without touch or proprioception: evidence from individuals with congenital and acquired neuropathy

“…We suggest that he was more strategic, top-down, in his approach-and possibly more cautious about the invalid and catch trials-as he was in a previous attentional task (Nougier et al 1994). IW prefers a cautious approach in tasks that he wishes to perform as well as possible (Renault et al 2018). There were certainly no signs of any subconscious proximity advantage for IW.…”

“…However, we report digit lengths (the distance between the mean reported location of the primary knuckle and fingertip of each digit) and hand width (the distance between the primary knuckle of the index and little finger), as these measures are unaffected by spread of the fingers. To compare each test participant with their respective control group, condition-specific Q' scores were calculated (equivalent to case-control t scores) and across-condition Q' scores used to test if the variations in the case-control differences across the factors (hand and digit) were significant (Michael 2007;Renault et al 2018).…”