During execution and observation of reaching-grasping actions, the brain must encode, at the same time, the final action goal and the type of grip necessary to achieve it. Recently, it has been proposed that the Mirror Neuron System (MNS) is involved not only in coding the final goal of the observed action, but also the type of grip used to grasp the object. However, the specific contribution of the different areas of the MNS, at both cortical and subcortical level, in disentangling action goal and grip type is still unclear. Here, twenty human volunteers participated in an fMRI study in which they performed two tasks: (a) observation of four different types of actions, consisting in reaching-to-grasp a box handle with two possible grips (precision, hook) and two possible goals (open, close); (b) action execution, in which participants performed grasping actions similar to those presented during the observation task. A conjunction analysis revealed the presence of shared activated voxels for both action observation and execution within several cortical areas including dorsal and ventral premotor cortex, inferior and superior parietal cortex, intraparietal sulcus, primary somatosensory cortex, and cerebellar lobules VI and VIII. ROI analyses showed a main effect for grip type in several premotor and parietal areas and cerebellar lobule VI, with higher BOLD activation during observation of precision vs hook actions. A grip x goal interaction was also present in the left inferior parietal cortex, with higher BOLD activity during precision-to-close actions. A multivariate pattern analysis (MVPA) revealed a significant accuracy for the grip model in all ROIs, while for the action goal model, significant accuracy was observed only for left inferior parietal cortex ROI. These findings indicate that a large network involving cortical and cerebellar areas is involved in the processing of type of grip, while final action goal appears to be mainly processed within the inferior parietal region, suggesting a differential contribution of the areas activated in this study.

在执行和观察伸手抓握动作的过程中，大脑必须同时编码最终的动作目标和实现该目标所需的抓握类型。最近，有人提出，镜像神经元系统 (MNS) 不仅参与编码观察到的动作的最终目标，还涉及用于抓握物体的抓握类型。然而，MNS 不同区域（在皮质和皮质下水平）在解开动作目标和握持类型方面的具体贡献仍不清楚。在这里，20 名人类志愿者参与了一项 fMRI 研究，他们在其中执行了两项任务：(a) 观察四种不同类型的动作，包括伸手去抓一个盒子把手，该把手有两个可能的把手（精确度、钩子）和两个可能的把手目标（开关）; (b) 动作执行，参与者执行类似于观察任务期间呈现的抓取动作。联合分析显示，在几个皮质区域（包括背侧和腹侧运动前皮层、下顶叶皮层、顶叶内沟、初级体感皮层和小脑小叶 VI 和 VIII）内存在用于动作观察和执行的共享激活体素。ROI 分析显示，在几个运动前区和顶叶区以及小脑小叶 VI 中，握持类型的主要影响，在观察精度与钩动作时具有更高的 BOLD 激活。一个抓地力x目标左下顶叶皮层也存在相互作用，在精确到关闭动作期间具有更高的 BOLD 活动。多变量模式分析 (MVPA) 揭示了所有 ROI 中握持模型的显着准确性，而对于动作目标模型，仅在左下顶叶皮层 ROI 中观察到显着的准确性。这些发现表明，涉及皮质和小脑区域的大型网络参与了抓握类型的处理，而最终动作目标似乎主要在下顶叶区域内处理，表明本研究中激活的区域的不同贡献。