Garbarini Francesca, Rabuffetti Marco, Piedimonte Alessandro, Solito Gianluca, Berti Anna
SAMBA - SpAtial, Motor & Bodily Awareness - Research Group, Department of Psychology, University of Turin, 10123 Turin, Italy.
Biomedical Technology Department, Found. Don Carlo Gnocchi IRCCS, 20148 Milan, Italy.
Hum Mov Sci. 2015 Jun;41:114-26. doi: 10.1016/j.humov.2015.03.003. Epub 2015 Mar 19.
When humans simultaneously perform different movements with both hands, each limb movement interferes with the contralateral limb movement (bimanual coupling). Previous studies on both healthy volunteers and patients with central or peripheral nervous lesions suggested that such motor constraints are tightly linked to intentional motor programs, rather than to movement execution. Here, we aim to investigate this phenomenon, by using a circles-lines task in which, when subjects simultaneously draw lines with the right hand and circles with the left hand, both the trajectories tend to become ovals (bimanual coupling effect). In a first group, we immobilized the subjects' left arm with a cast and asked them to try to perform the bimanual task. In a second group, we passively moved the subjects' left arm and asked them to perform voluntary movements with their right arm only. If the bimanual coupling arises from motor intention and planning rather than spatial movements, we would expect different results in the two groups. In the Blocked group, where motor intentionality was required but movements in space were prevented by immobilization of the arm, a significant coupling effect (i.e., a significant increase of the ovalization index for the right hand lines) was found. On the contrary, in the Passive group, where movements in space were present but motor intentionality was not required, no significant coupling effect was observed. Our results confirmed, in healthy subjects, the central role of the intentional and predictive operations, already evidenced in pathological conditions, for the occurrence of bimanual coupling.
当人类双手同时进行不同动作时，每个肢体的动作都会干扰对侧肢体的动作（双手耦合）。先前针对健康志愿者以及中枢或周围神经损伤患者的研究表明，这种运动限制与意向性运动程序紧密相关，而非与动作执行相关。在此，我们旨在通过使用一种圆圈 - 线条任务来研究这一现象，即在该任务中，当受试者右手画线条而左手画圆圈时，两条轨迹往往都会变成椭圆形（双手耦合效应）。在第一组中，我们用石膏固定受试者的左臂，并要求他们尝试完成双手任务。在第二组中，我们被动地移动受试者的左臂，并要求他们仅用右臂进行自主运动。如果双手耦合源于运动意图和计划而非空间动作，我们预计两组会有不同的结果。在“固定组”中，虽然需要运动意向，但手臂固定阻止了空间中的动作，结果发现存在显著的耦合效应（即右手线条的椭圆化指数显著增加）。相反，在“被动组”中，虽然存在空间中的动作，但不需要运动意向，未观察到显著的耦合效应。我们的结果证实，在健康受试者中，意向性和预测性操作在双手耦合的发生中起着核心作用，这在病理状况下已得到证实。
