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Robert L. Sainburg and Pratik K. Mutha

The target article (Smeets, Oostwoud Wijdenes, & Brenner, 2016) proposes that short latency responses to changes in target location during reaching reflect an unconscious, continuous, and incremental minimization of the distance between the hand and the target, which does not require detection of the change in target location. We, instead, propose that short-latency visuomotor responses invoke reflex- or startle-like mechanisms, an idea supported by evidence that such responses are both automatic and resistant to cognitive influences. In addition, the target article fails to address the biological underpinnings for the range of response latencies reported across the literature, including the circuits that might underlie the proposed sensorimotor loops. When considering the range of latencies reported in the literature, we propose that mechanisms grounded in neurophysiology should be more informative than the simple information processing perspective adopted by the target article.

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Niamh Reilly, Gavin P. Lawrence, Thomas Mottram and Michael Khan

The perceptual-motor impairments of individuals with Down syndrome (DS) are attributed to central (e.g., neurophysiology deficits that affect the retrieval or initiation of motor programs) and peripheral (e.g., anatomical deficits relating to issues with inertia of limb mechanics and muscle organization) processes. However, recent research suggests that central deficits do not affect the integration between movements. We investigate the impact of central and peripheral DS deficits on movement integration by examining the planning and execution of multiple-target multiple-arm movements. Individuals with DS, typically developing (TD), and individuals with an undifferentiated intellectual disability (UID) completed five aiming tasks: a one target; a one-arm, two-target extension; a two-arm, two-target extension (movement one was performed with one arm and movement two performed with the other); a one-arm, two-target reversal; and a two-arm, two-target reversal. Movement times (MTs) to the first target were longer in the two-target tasks compared with the one-target task. For the one-arm, two-target reversal task, this effect emerged only in individuals with DS. These results indicate that individuals with DS use central processing for movement integration similarly to their TD and UID counterparts but cannot exploit peripheral-level integration to enhance integration in one-arm reversal tasks.

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Onno G. Meijer, Yakov M. Kots and V. Reggie Edgerton

In 1963, an article on “Tonus” (tone), written by Nikolai A. Bernstein and Yakov M. Kots. appeared in the second edition of the Bols'aja Medicinskaja Enciclopedija [Grand Medical Encyclopedia]. The paper is now published for the first time in the English language, with Mark L. Latash as translator. In accordance with then contemporary neurophysiology and neuropsychology, the paper presented “tone” as a graded phenomenon (as opposed to all-or-none), serving to prepare the segmental level for phasic contractions. Influenced by Granit and Matthews, the authors proposed that the suprasegmental level controls the threshold and the slope of the stretch reflex. In their introduction to the present edition, the editors understand this proposal in the context of low-dimensional control, that is. control in terms of one or a few variables (as opposed to central commands specifying all the details). Selected episodes from the history of low dimensional control and its logical counterpart, spinal intelligence, are used to illustrate how difficult these ideas were to accept. As so often in new scientific developments, confusion was the rule, and in this respect the paper on “Tonus” is no exception. In the epilogue, Kots gives his personal memories of the context in which the paper was written. At the time, he was working on “equitonometry” (equitonometric), measuring tonic balance with gravity eliminated. Results of equitonometric research quite naturally led to the idea that suprasegmental centers control the threshold and the slope of me tonic stretch reflex. As Kots remembers, that was “no big deal.”

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Mark L. Latash

, 16, 416 – 426 . doi: 10.1080/17461391.2015.1068869 Evarts , E.V. ( 1968 ). Relation of pyramidal tract activity to force exerted during voluntary movement . Journal of Neurophysiology, 31, 14 – 27 . PubMed ID: 4966614 doi: 10.1152/jn.1968.31.1.14 Farina , D. , Merletti , R. , & Enoka

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Aviroop Dutt-Mazumder, Richard L. Segal and Aiko K. Thompson

loading in standing, this study, in combination with those previous studies, may provide insight into complex neurophysiology of a simple yet significant motor task of standing. Acknowledgments This study was supported by RLS startup fund, NINDS ( NS069551 to A.K. Thompson), South Carolina Spinal Cord

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Momoko Yamagata, Ali Falaki and Mark L. Latash

during antagonist cocontraction and reciprocal inhibition of forearm muscles . Journal of Neurophysiology, 51 , 32 – 49 . PubMed ID: 6693934 doi:10.1152/jn.1984.51.1.32 10.1152/jn.1984.51.1.32 Gelfand , I.M. , & Latash , M.L. ( 1998 ). On the problem of adequate language in movement science

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Julie Vaughan-Graham, Kara Patterson, Karl Zabjek and Cheryl A. Cott

. Beyaert , C. , Vasa , R. , & Frykberg , G. ( 2015 ). Gait post-stroke: Pathophysiology and rehabilitation strategies . Clinical Neurophysiology, 45 ( 4–5 ), 335 – 355 . PubMed ID: 26547547 doi:10.1016/j.neucli.2015.09.005 10.1016/j.neucli.2015.09.005 Borich , M. , Brodie , S. , Gray , W

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Iraj Derakhshan

start in the major hemisphere . Clinical Neurophysiology, 127 , 3195 – 3196 . PubMed doi:10.1016/j.clinph.2016.05.367 10.1016/j.clinph.2016.05.367 Gutnik , B. , & Hyland , B. ( 1997 ). Spatial coordination in a bimanual task related to regular switching of movement vectors . Perceptual and

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Afshin Samani and Mathias Kristiansen

and muscle coordination complexity post-stroke . Journal of Neurophysiology, 103 ( 2 ), 844 – 857 . PubMed doi:10.1152/jn.00825.2009 10.1152/jn.00825.2009 Danna-Dos-Santos , A. , Shapkova , E.Y. , Shapkova , A.L. , Degani , A.M. , & Latash , M.L. ( 2009 ). Postural control during upper

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Carol A. Boliek, Reyhaneh Bakhtiari, Lauren Pedersen, Julia R. Esch and Jacqueline Cummine

. American Journal of Respiratory and Critical Care Medicine, 166 , 518 – 624 . doi:10.1164/rccm.166.4.518 Brown , P. , Salenius , S. , Rothwell , J.C. , & Hari , R. ( 1998 ). Cortical correlate of the Piper rhythm in humans . Journal of Neurophysiology, 80 , 2911 – 2917 . PubMed doi:10