Barthélémy Sébastien, Boulinguez Philippe
Laboratoire d'Analyse de la Performance Motrice Humaine, EA 2254, Université de Poitiers, Poitiers, France.
Exp Brain Res. 2002 Dec;147(3):305-12. doi: 10.1007/s00221-002-1247-x. Epub 2002 Oct 17.
Directional coding of hand movements is of primary importance in the proactive control of goal-directed aiming. At the same time, manual reaction times are known to be asymmetric when reaching at lateralized targets. Generally, ipsilateral movements and left hand advantages are interpreted using the classical model of interhemispheric transmission for simple visuomotor integration, but the use of this model was recently challenged when applied to reaching movements, arguing that attentional and biomechanical effects could also account for such asymmetries. In this work, we aimed at controlling both visual attention orienting and movement mechanical constraints in order to clarify the origin of manual reaction time asymmetries and hemispatial effects in the directional coding of reaching. Choice reaction time pointing tasks were assessed in two experiments in which identical movements were compared in different conditions of target lateralization and different conditions of head, eye and hand position. Results suggested that biomechanical constraints could account for hemispatial effects for movement execution but not for movement direction coding. These results are discussed in the light of models of interhemispheric cooperation and the right hemisphere dominance for spatial processing.
手部动作的方向编码在目标导向性瞄准的主动控制中至关重要。与此同时，已知在向侧化目标伸手时，手动反应时间是不对称的。一般来说，同侧动作和左手优势是使用经典的半球间传递模型来解释简单视运动整合的，但该模型在应用于伸手动作时最近受到了挑战，有人认为注意力和生物力学效应也可以解释这种不对称性。在这项研究中，我们旨在控制视觉注意力定向和运动机械约束，以阐明手动反应时间不对称和伸手方向编码中的半空间效应的起源。在两个实验中评估了选择反应时间指向任务，其中在不同的目标侧化条件以及不同的头部、眼睛和手部位置条件下比较了相同的动作。结果表明，生物力学约束可以解释运动执行中的半空间效应，但不能解释运动方向编码中的半空间效应。根据半球间合作模型和右半球在空间处理方面的优势对这些结果进行了讨论。
