Chang Liangtang, Fang Qin, Zhang Shikun, Poo Mu-Ming, Gong Neng
Institute of Neuroscience and Key Laboratory of Primate Neurobiology, CAS Center for Excellence in Brain Science, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.
Institute of Neuroscience and Key Laboratory of Primate Neurobiology, CAS Center for Excellence in Brain Science, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.
Curr Biol. 2015 Jan 19;25(2):212-217. doi: 10.1016/j.cub.2014.11.016. Epub 2015 Jan 8.
Mirror self-recognition is a hallmark of higher intelligence in humans. Most children recognize themselves in the mirror by 2 years of age. In contrast to human and some great apes, monkeys have consistently failed the standard mark test for mirror self-recognition in all previous studies. Here, we show that rhesus monkeys could acquire mirror-induced self-directed behaviors resembling mirror self-recognition following training with visual-somatosensory association. Monkeys were trained on a monkey chair in front of a mirror to touch a light spot on their faces produced by a laser light that elicited an irritant sensation. After 2-5 weeks of training, monkeys had learned to touch a face area marked by a non-irritant light spot or odorless dye in front of a mirror and by a virtual face mark on the mirroring video image on a video screen. Furthermore, in the home cage, five out of seven trained monkeys showed typical mirror-induced self-directed behaviors, such as touching the mark on the face or ear and then looking at and/or smelling their fingers, as well as spontaneously using the mirror to explore normally unseen body parts. Four control monkeys of a similar age that went through mirror habituation but had no training of visual-somatosensory association did not pass any mark tests and did not exhibit mirror-induced self-directed behaviors. These results shed light on the origin of mirror self-recognition and suggest a new approach to studying its neural mechanism.
镜像自我识别是人类高智商的一个标志。大多数儿童在2岁时就能在镜子中认出自己。与人类和一些大猩猩不同，在以往所有研究中，猴子始终未能通过镜像自我识别的标准标记测试。在此，我们表明，恒河猴在接受视觉-体感关联训练后，可以习得类似于镜像自我识别的由镜子引发的自我导向行为。猴子被安置在镜子前的猴椅上进行训练，触摸由激光产生的脸上的亮点，该亮点会引发刺激感。经过2至5周的训练，猴子学会了在镜子前触摸由无刺激亮点或无味染料标记的面部区域，以及视频屏幕上镜像视频图像上的虚拟面部标记。此外，在猴舍中，7只经过训练的猴子中有5只表现出典型的由镜子引发的自我导向行为，比如触摸脸上或耳朵上的标记，然后看着和/或闻自己的手指，以及自发地用镜子探索通常看不到的身体部位。4只年龄相仿的对照猴子经历了镜子习惯化，但没有接受视觉-体感关联训练，它们没有通过任何标记测试，也没有表现出由镜子引发的自我导向行为。这些结果揭示了镜像自我识别的起源，并为研究其神经机制提供了一种新方法。
