School of Psychology, Bangor University, Bangor, United Kingdom.
J Neurophysiol. 2010 Aug;104(2):1077-89. doi: 10.1152/jn.00326.2010. Epub 2010 Jun 10.
Many lines of evidence point to a tight linkage between the perceptual and motoric representations of actions. Numerous demonstrations show how the visual perception of an action engages compatible activity in the observer's motor system. This is seen for both intransitive actions (e.g., in the case of unconscious postural imitation) and transitive actions (e.g., grasping an object). Although the discovery of "mirror neurons" in macaques has inspired explanations of these processes in human action behaviors, the evidence for areas in the human brain that similarly form a crossmodal visual/motor representation of actions remains incomplete. To address this, in the present study, participants performed and observed hand actions while being scanned with functional MRI. We took a data-driven approach by applying whole-brain information mapping using a multivoxel pattern analysis (MVPA) classifier, performed on reconstructed representations of the cortical surface. The aim was to identify regions in which local voxelwise patterns of activity can distinguish among different actions, across the visual and motor domains. Experiment 1 tested intransitive, meaningless hand movements, whereas experiment 2 tested object-directed actions (all right-handed). Our analyses of both experiments revealed crossmodal action regions in the lateral occipitotemporal cortex (bilaterally) and in the left postcentral gyrus/anterior parietal cortex. Furthermore, in experiment 2 we identified a gradient of bias in the patterns of information in the left hemisphere postcentral/parietal region. The postcentral gyrus carried more information about the effectors used to carry out the action (fingers vs. whole hand), whereas anterior parietal regions carried more information about the goal of the action (lift vs. punch). Taken together, these results provide evidence for common neural coding in these areas of the visual and motor aspects of actions, and demonstrate further how MVPA can contribute to our understanding of the nature of distributed neural representations.
许多证据表明，动作的知觉和运动表现之间存在紧密的联系。大量的研究表明，动作的视觉感知会引起观察者运动系统的兼容活动。这既适用于非传递性动作（例如无意识的姿势模仿），也适用于传递性动作（例如抓取物体）。尽管在猕猴中发现了“镜像神经元”，但这些过程在人类动作行为中的解释仍然不完整。为了解决这个问题，在本研究中，参与者在进行和观察手部动作的同时接受 fMRI 扫描。我们采用了一种数据驱动的方法，通过应用多体素模式分析（MVPA）分类器对皮质表面的重建表示进行全脑信息映射。目的是识别能够在视觉和运动领域区分不同动作的局部体素活动模式的区域。实验 1 测试了非传递性、无意义的手部运动，而实验 2 测试了指向物体的动作（均为右手）。我们对这两个实验的分析都揭示了外侧枕颞皮质（双侧）和左侧后中央回/前顶叶皮质中的跨模态动作区域。此外，在实验 2 中，我们在左侧后中央/顶叶区域的信息模式中发现了一种偏向梯度。后中央回携带有关执行动作的效应器（手指与整个手）的更多信息，而前顶叶区域则携带有关动作目标（提升与拳击）的更多信息。总之，这些结果为视觉和运动动作方面这些区域的共同神经编码提供了证据，并进一步展示了 MVPA 如何有助于我们理解分布式神经表示的性质。
