Synthesis
motor behaviors, motor dysfunction, ’
POSTERIOR
Reviewing Editor: Mark Laubach, American UniversityDecisions are customarily a result of the Reviewing Editor and the peer reviewers coming together and discussing their recommendations until a consensus is reached. When revisions are invited, a fact-based synthesis statement explaining their decision and outlining what is needed to prepare a revision will be listed below. The following reviewer(s) agreed to reveal their identity: Qiushi Fu.Your paper was reviewed by two experts and there are some essential revisions to do. Please address all points raised in the reviews below. Thank you.Reviewer 1In this paper the authors examined the characteristics of motor adaptation of either the right (dominant) or the left (non-dominant) arms. There were two experimental paradigms, Exp 1 was a standard adaptation protocol with consistent force field reaching, whereas Exp 2 was random force field reaching. In both paradigms, the left and right hands were chosen randomly to limit the potential confound of inter-limb transfer. The motor behaviors were quantified with movement kinematics and kinetics, as well as EMG. Some differences in motor adaptation and control strategies were found between limbs. I have the following commentsMajor- A more in-depth discussion of ‘robust control’ and ‘impedance control’ is needed. This should be strengthened by (1) a better explanation of what ‘robust control’ is, (2) a more updated view of Sainburg’s lateralization framework (use more recent work from Sainburg’s group and others), (3) the key differences between these two control policies, and (4) why the data supports one vs the other.- Please justify the focus on Pectoralis Major and Posterior Deltoid muscles. How about elbow actuators (biceps/triceps)? Furthermore, why did the authors choose the 100ms window before movement onset, Instead of a window during movement, for measuring the co-contraction (thereby the impedance control) strategy?- Discuss the differences between force field directions (Fig. 6)- A methodological difference between this study and some other recent motor adaptation studies is the use of ‘catch trials’ vs. ‘clamp trials’. Given the nature of ‘catch trials’, one could argue that Exp 1 is a somewhat ‘random’ perturbation schedule as well (1 out of 5 being non-FF). Could this ‘randomness’ lead to the differences in adaptation of the two limbs? Note that ‘clamp trials’ could potentially minimize such effect. Please explain this methodological decision.Minor- The units used in the graphs are sometimes inconsistent. I suggest always use the same (m, cm, or mm) for consistency.- 3 out 12 subjects had electrode disconnect is a bit too high.- In Exp1, the post-hoc analysis sometimes examined the first and last (single) trials, and sometimes the last 20 trials. I think it can be more consistently structured, e.g., always use the first n and last n trials (n>1, considering the single trial variance)Reviewer 2In this interesting study, authors asked whether there is difference in control strategies between left and right arm during a conventional adaptation task in neurotypical adults. They ran two experiments. The main finding was that the non-dominant limb showed a robust control strategy during the force field adaptation.StrengthsAuthors do acknowledge that there was a previous work on this matter, they do identify the two limitations/gaps, and then they ran this experiment by “correcting” these limitations gaps. Important question to ask; better understanding of this matter can help in rehabilitation of motor dysfunction in neurological cohorts.Major Concerns:Given that the use of computational approaches are mentioned in the abstract, there is limited description/mentioning of those approaches in the introduction. Authors should consider adding the relative information and the importance of using these approaches to answer the specific question asked here.Minor Concerns:AbstractAuthors mentioned the lack of computational aspects as a gap but they don’t even state the models used here in a later section of the abstract. Please elaborate.Authors should briefly state that two experiments were ran here; plus the N and that EMG was collected (they do mention co-contraction in the results).Is predictive vs. impedance the same as predictive vs. reactive?IntroductionLines 56-59: Authors should elaborate more on the robust control strategy so it is intuitive to the reader what this strategy is about.MethodsGiven that subjects in both experiments were self-identified as right-handed, authors should acknowledge that as a potential methodological consideration in the limitation section.Lines 106-107: Authors should briefly elaborate on why all trials were included in the analysis independent of time window.Line 121: Given that a standard adaptation paradigm was used, authors should consider cite the original paper(s) that employed this paradigm.Data analysisAuthors should consider restructure this sectioni.e., present the data analysis per experiment - Exp 1 & 2Any similarities between the two experiments, just state them.Line 173: Mixed-model analyses - please explicitly state which onesFor the measures analyzed in both experiments, use the abbreviations across the text.ResultsWhere is necessary, authors should consider adding effect sizes.Discussion/ConclusionWell written yet a limitation section has been omitted. Authors should consider adding one.