Binkofski Ferdinand, Buccino Giovanni
Division of Clinical Cognitive Sciences, Medical Faculty of the RWTH Aachen University, Aachen, Germany.
Department of Physiology, Medical Faculty of the University of Magna Graecia, Catanzaro, Italy.
Handb Clin Neurol. 2018;151:467-479. doi: 10.1016/B978-0-444-63622-5.00024-3.
The picture of the human cortical motor system has fully changed in the last two decades. In the light of new data, the notion of a motor system devoted solely to action execution, strictly isolated from the sensory system, is not sustainable. There is evidence that parietal areas are strictly connected to frontal areas and these connections build up sensorimotor circuits aimed at interacting with objects in the environment, and at understanding actions. They are known as the canonic neuron system and mirror neuron system, respectively. These circuits are part of the classic dorsal stream. Recently, the dorsal stream has been further divided into a dorsodorsal and a ventrodorsal stream. The ventrodorsal stream is regarded as functionally linked to object awareness for action recognition/organization. The dorsodorsal stream is proposed to subserve online control of actions. Affordances indicate "action possibilities" as characterized by object properties the environment provides to interacting organisms. Affordances may be divided into stable and variable ones. According to this distinction, stable affordances emerge from slow offline processing of visual information based on object knowledge as well as previous experiences in object interaction. In contrast, variable affordances emerge from fast online processing of visual information during actual object interaction and refer to changing or temporary object characteristics, such as orientation in space, size changes, including the update of hand shape for grasping, defining overall the current state of the object. It has been proposed that the dorsodorsal stream codes for variable affordances, while the dorsoventral stream codes for stable affordances.
在过去二十年中，人类皮质运动系统的情况已完全改变。根据新的数据，那种认为运动系统仅专门用于动作执行且与感觉系统严格隔离的观念已无法立足。有证据表明，顶叶区域与额叶区域紧密相连，这些连接构建了旨在与环境中的物体相互作用并理解动作的感觉运动回路。它们分别被称为典型神经元系统和镜像神经元系统。这些回路是经典背侧通路的一部分。最近，背侧通路又进一步分为背背侧通路和腹背侧通路。腹背侧通路在功能上被认为与用于动作识别/组织的物体感知相关联。背背侧通路则被认为有助于动作的在线控制。可供性表明“动作可能性”，其特征在于环境为相互作用的生物体提供的物体属性。可供性可分为稳定的和可变的。根据这种区分，稳定的可供性源于基于物体知识以及先前物体交互经验对视觉信息进行的缓慢离线处理。相比之下，可变的可供性源于实际物体交互过程中对视觉信息的快速在线处理，并且涉及不断变化或临时的物体特征，例如空间方向、大小变化，包括为抓握而更新的手形，总体上定义了物体的当前状态。有人提出，背背侧通路编码可变的可供性，而腹背侧通路编码稳定的可供性。
