Stella Maris Scientific Institute, Via dei Giacinti, 2 I-56128 Calambrone, Pisa, Italy.
Brain Res Bull. 2010 Mar 16;81(4-5):434-40. doi: 10.1016/j.brainresbull.2009.12.002. Epub 2009 Dec 16.
Human and monkey studies clearly show that the anterior intraparietal area (AIP) is crucial for hand-related visuomotor transformations. Human AIP activates also during observation of hand actions, involving it in the mirror system. It is not known, however, whether its activation can also reflect a difference in the complexity of the observed action. In the present study we used functional magnetic resonance imaging (fMRI) to explore the activation of human area AIP during the observation of complex object-manipulation tasks (e.g. inserting a key in a lock and turning it) as compared to simple tasks (whole hand grasping of an object) executed with the left and the right hand in a first person perspective. The results show that, in general, both complex and simple tasks produced an activation of the fronto-parietal mirror system and that the activity of AIP in each hemisphere was higher during observation of the contralateral hand (hand identity effect). A Region-Of-Interest (ROI) analysis of the parietal activations responding to hand identity showed that each AIP was more active during the observation of complex with respect to simple tasks. In the right AIP this effect was stronger during observation of the contralateral hand, in the left AIP was strong during observation of both hands. This complexity-related property was not observed in the other activated areas. These findings support the concept that the observation of motor acts retrieves the internal representation of those same acts in the observer's motor system (direct-matching hypothesis based on the mirror neuron mechanism).
人类和猴子的研究清楚地表明，前顶内沟（AIP）对于手相关的运动转换至关重要。人类 AIP 在观察手部动作时也会激活，使其参与到镜像系统中。然而，目前还不清楚其激活是否也能反映出所观察到的动作的复杂性差异。在本研究中，我们使用功能磁共振成像（fMRI）来探索人类 AIP 在观察复杂的物体操作任务（例如将钥匙插入锁并转动它）与简单任务（用左手和右手以第一人称视角进行整个手抓物体）时的激活情况。结果表明，一般来说，复杂和简单的任务都会产生额顶叶镜像系统的激活，并且在观察对侧手（手身份效应）时，每个半球的 AIP 活动更高。对响应手身份的顶叶激活进行的感兴趣区域（ROI）分析表明，在观察复杂任务时，每个 AIP 比简单任务更活跃。在右 AIP 中，这种效应在观察对侧手时更强，而在左 AIP 中，在观察双手时更强。在其他激活区域中没有观察到这种与复杂性相关的特性。这些发现支持了这样一种观点，即观察运动行为会在观察者的运动系统中检索到这些行为的内部表示（基于镜像神经元机制的直接匹配假说）。
