Uchimura Motoaki, Nakano Tamami, Morito Yusuke, Ando Hiroshi, Kitazawa Shigeru
Dynamic Brain Network Laboratory, Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka, 565-0871, Japan.
Department of Brain Physiology, Graduate School of Medicine, Osaka University, 1-3 Yamadaoka, Suita, Osaka, 565-0871, Japan.
Eur J Neurosci. 2015 Jul;42(1):1651-9. doi: 10.1111/ejn.12935. Epub 2015 May 21.
Our brains represent the position of a visual stimulus egocentrically, in either retinal or craniotopic coordinates. In addition, recent behavioral studies have shown that the stimulus position is automatically represented allocentrically relative to a large frame in the background. Here, we investigated neural correlates of the 'background coordinate' using an fMRI adaptation technique. A red dot was presented at different locations on a screen, in combination with a rectangular frame that was also presented at different locations, while the participants looked at a fixation cross. When the red dot was presented repeatedly at the same location relative to the rectangular frame, the fMRI signals significantly decreased in the right precuneus. No adaptation was observed after repeated presentations relative to a small, but salient, landmark. These results suggest that the background coordinate is implemented in the right precuneus.
我们的大脑以自我中心的方式，在视网膜或颅顶坐标中表征视觉刺激的位置。此外，最近的行为研究表明，刺激位置会相对于背景中的一个大框架自动以空间参照的方式被表征。在此，我们使用功能磁共振成像适应技术研究了“背景坐标”的神经关联。在屏幕上的不同位置呈现一个红点，并结合一个也在不同位置呈现的矩形框架，同时让参与者注视一个固定十字。当红点相对于矩形框架在同一位置重复呈现时，右侧楔前叶的功能磁共振信号显著下降。相对于一个小但显著的地标重复呈现后未观察到适应现象。这些结果表明，背景坐标在右侧楔前叶中得以实现。
