Shimada Sotaro, Hiraki Kazuo
Department of General System Studies, The University of Tokyo, 3-4-1, Komaba, Meguro-ku, Tokyo, 153-8902, Japan.
Neuroimage. 2006 Aug 15;32(2):930-9. doi: 10.1016/j.neuroimage.2006.03.044. Epub 2006 May 6.
Whether human infants perceive televised stimuli in the same way to live stimuli largely remains unknown. Action observation, which has been extensively confirmed to elicit activation of internal motor representation, provides a promising framework for investigating this issue. This 'mirror-matching' property has been found in the monkey premotor cortex as well as the premotor and primary motor cortices in human adults. Although larger activation in observing a live action compared to a televised action in adult subjects has been reported, it is unknown whether the same neural response is obtained from human infants. To address this issue, we first measured the activity of motor areas in adult subjects while viewing either a live or televised action of other people by using near-infrared spectroscopy. The motor areas that were activated when the subject themselves performed an action were also activated during action observation in the live setting, while this was not evident in the TV setting. We then conducted qualitatively the same experiment with 6- to 7-month-old infants. The infant's motor areas were significantly activated when observing a live person performing an action. Although we also found activation in the same area during action observation in the TV setting, the difference in activity between action observation and object-motion observation was significant only in the live setting. Our results are the first to demonstrate activation in motor areas during action observation in human infants. We suggest that human brain responds differently to the real world and the virtual world.
人类婴儿对电视刺激的感知方式是否与对真实刺激的感知方式相同，在很大程度上仍然未知。动作观察已被广泛证实能引发内部运动表征的激活，为研究这个问题提供了一个有前景的框架。这种“镜像匹配”特性已在猴子的前运动皮层以及成年人类的前运动皮层和初级运动皮层中被发现。尽管有报道称，与观看电视动作相比，成年受试者在观察真实动作时激活程度更高，但尚不清楚人类婴儿是否会有相同的神经反应。为了解决这个问题，我们首先使用近红外光谱技术，测量了成年受试者在观看他人的真实动作或电视动作时运动区域的活动。当受试者自己执行动作时被激活的运动区域，在观察真实动作时也会被激活，但在观看电视动作时则不明显。然后，我们对6至7个月大的婴儿进行了定性相同的实验。婴儿在观察真人执行动作时，其运动区域会显著激活。虽然我们在观看电视动作时的观察过程中也发现了相同区域的激活，但动作观察和物体运动观察之间的活动差异仅在观察真实动作时显著。我们的研究结果首次证明了人类婴儿在动作观察过程中运动区域的激活。我们认为，人类大脑对现实世界和虚拟世界的反应是不同的。
