Sartori Luisa, Camperio-Ciani Andrea, Bulgheroni Maria, Castiello Umberto
Department of General Psychology, University of Padua, Via Venezia 8, 35131, Padua, Italy.
Exp Brain Res. 2014 Mar;232(3):919-25. doi: 10.1007/s00221-013-3804-x. Epub 2013 Dec 15.
Although there is a wealth of behavioral data regarding grasping movements in non-human primates, how posture influences the kinematics of prehensile behavior is not yet clearly understood. The purpose of this study was to examine and compare kinematic descriptions of grip behaviors while primates (macaque monkeys) were in a sitting posture or when stopping after quadrupedal locomotion (i.e., tripedal stance). Video footage taken while macaques grasped objects was analyzed frame-by-frame using digitalization techniques. Each of the two grip types considered (power and precision grips) was found to be characterized by specific, distinct kinematic signatures for both the reaching and the grasping components when those actions were performed in a sitting position. The grasping component did not differentiate in relation to the type of grip that was needed when, instead, the prehensile action took place in a tripedal stance. Quadrupedal locomotion affected the concomitant organization of prehensile activities determining in fact a similar kinematic patterning for the two grips regardless of the size of the object to be grasped. It is suggested that using a single kinematic grip patterning for all prehensile activities might be both the by-product of planning a grasping action while walking and a way to simplify motor programming during unstable tripedal stance.
尽管有大量关于非人类灵长类动物抓握动作的行为数据，但姿势如何影响抓握行为的运动学仍未得到清晰的理解。本研究的目的是检查和比较灵长类动物（猕猴）处于坐姿或四足运动后停下（即三足站立）时抓握行为的运动学描述。使用数字化技术对猕猴抓握物体时拍摄的视频片段逐帧进行分析。当在坐姿下执行这些动作时，所考虑的两种抓握类型（强力抓握和精确抓握）中的每一种都被发现具有针对伸手和抓握部分的特定、独特的运动学特征。相反，当抓握动作在三足站立姿势下进行时，抓握部分与所需的抓握类型无关。四足运动影响了抓握活动的伴随组织，实际上决定了无论要抓握物体的大小如何，两种抓握方式都具有相似的运动学模式。有人认为，对所有抓握活动使用单一的运动学抓握模式可能既是在行走时计划抓握动作的副产品，也是在不稳定的三足站立姿势下简化运动编程的一种方式。
