Department of Basic Sciences, School of Medicine, University of Crete, PO Box 2208, 71003 Iraklion, Greece.
Computational Neuroscience Group, Institute of Applied and Computational Mathematics, Foundation for Research and Technology-Hellas, Plastira N 100 str, 71003 Iraklion, Greece.
Cereb Cortex. 2019 Sep 13;29(10):4223-4237. doi: 10.1093/cercor/bhy304.
We identified neurons in dorsal premotor cortex (PMd) of the macaque brain that respond during execution and observation of reaching-to-grasp actions, thus fulfilling the mirror neuron (MirN) criterion. During observation, the percentage of grip-selective MirNs in PMd and area F5 were comparable, and the selectivity indices in the two areas were similar. During execution, F5-MirNs were more selective than PMd-MirNs for grip, which was reflected in the higher selectivity indices in F5 than in PMd. PMd displayed grip-related information earlier than F5 during both conditions. In both areas, the number of neurons exhibiting congruent visual and motor selectivity did not differ from that expected by chance. However, both the PMd and F5 neuronal ensembles provided observation-execution matching, suggesting that the congruency may be achieved in a distributed fashion across the selective elements of the population. Furthermore, representational similarity analysis revealed that grip encoding in PMd and F5 is alike during both observation and execution. Our study provides direct evidence of mirror activity in PMd during observation of forelimb movements, and suggests that PMd is a node of the MirN circuit.
我们在猕猴大脑的背侧运动前皮层 (PMd) 中鉴定出在执行和观察伸手抓握动作期间反应的神经元，从而满足镜像神经元 (MirN) 的标准。在观察期间，PMd 和 F5 区中与抓握选择性相关的 MirN 的比例相当，并且两个区域的选择指数相似。在执行期间，F5-MirN 比 PMd-MirN 对抓握的选择性更高，这反映在 F5 中的选择指数高于 PMd。在两种情况下，PMd 比 F5 更早显示与抓握相关的信息。在两个区域中，表现出视觉和运动选择性一致的神经元数量与随机预期的数量没有差异。然而，PMd 和 F5 的神经元集合都提供了观察-执行匹配，这表明这种一致性可能以分布式方式在群体的选择性元素中实现。此外，表示相似性分析表明，在观察和执行期间，PMd 和 F5 中的抓握编码是相似的。我们的研究提供了在观察前肢运动期间 PMd 中镜像活动的直接证据，并表明 PMd 是 MirN 回路的一个节点。
