Department of Neuroscience, University of Parma, Via Volturno 39, 43100 Parma, Italy.
Exp Brain Res. 2010 Aug;204(4):605-16. doi: 10.1007/s00221-010-2329-9. Epub 2010 Jun 26.
Mirror neurons are a distinct class of neurons that discharge both during the execution of a motor act and during observation of the same or similar motor act performed by another individual. However, the extent to which mirror neurons coding a motor act with a specific goal (e.g., grasping) might also respond to the observation of a motor act having the same goal, but achieved with artificial effectors, is not yet established. In the present study, we addressed this issue by recording mirror neurons from the ventral premotor cortex (area F5) of two monkeys trained to grasp objects with pliers. Neuron activity was recorded during the observation and execution of grasping performed with the hand, with pliers and during observation of an experimenter spearing food with a stick. The results showed that virtually all neurons responding to the observation of hand grasping also responded to the observation of grasping with pliers and, many of them to the observation of spearing with a stick. However, the intensity and pattern of the response differed among conditions. Hand grasping observation determined the earliest and the strongest discharge, while pliers grasping and spearing observation triggered weaker responses at longer latencies. We conclude that F5 grasping mirror neurons respond to the observation of a family of stimuli leading to the same goal. However, the response pattern depends upon the similarity between the observed motor act and the one executed by the hand, the natural motor template.
镜像神经元是一类特殊的神经元，它们在执行运动行为和观察另一个个体执行相同或相似的运动行为时都会放电。然而，编码具有特定目标（例如抓握）的运动行为的镜像神经元是否也会对具有相同目标但使用人工效应器完成的运动行为的观察做出反应，目前尚不清楚。在本研究中，我们通过记录两只猴子的腹侧前运动皮层（F5 区）中的镜像神经元来解决这个问题，这两只猴子接受过使用钳子抓握物体的训练。在观察和执行手抓、用钳子抓握以及观察实验者用棍子叉食物的过程中，记录了神经元的活动。结果表明，几乎所有对观察手抓握有反应的神经元也对观察用钳子抓握有反应，其中许多神经元对观察用棍子叉食物也有反应。然而，反应的强度和模式在不同条件下有所不同。手抓握观察引发最早和最强的放电，而钳子抓握和用棍子叉食物观察则在更长的潜伏期引发较弱的反应。我们得出结论，F5 抓握镜像神经元对导致相同目标的一系列刺激的观察做出反应。然而，反应模式取决于观察到的运动行为与手执行的自然运动模板之间的相似性。
