Vision and Cognition Lab, Centre for Integrative Neuroscience, University of Tübingen, 72076 Tübingen, Germany.
Curr Biol. 2010 Dec 7;20(23):2106-11. doi: 10.1016/j.cub.2010.10.046. Epub 2010 Nov 18.
Human brain imaging studies of bistable perceptual phenomena revealed that frontal and parietal areas are activated during perceptual switches between the two conflicting percepts. However, these studies do not provide information about causality, i.e., whether activity reports a consequence or a cause of the perceptual change. Here we used functional magnetic resonance imaging to individually localize four parietal regions involved in perceptual switches during binocular rivalry in 15 subjects and subsequently disturbed their neural processing and that of a control site using 2 Hz repetitive transcranial magnetic stimulation (TMS) during binocular rivalry. We found that TMS over one of the sites, the right intraparietal sulcus (IPS), prolonged the periods of stable percepts. Additionally, the more lateralized the blood oxygen level-dependent signal was in IPS, the more lateralized the TMS effects were. Lateralization varied considerably across subjects, with a right-hemispheric bias. Control replay experiments rule out nonspecific effects of TMS on task performance, reaction times, or eye blinks. Our results thus demonstrate a causal, destabilizing, and individually lateralized effect of normal IPS function on perceptual continuity in rivalry. This is in accord with a role of IPS in perceptual selection, relating its role in rivalrous perception to that in attention.
人类大脑影像学研究双稳态感知现象表明，在前顶叶区域在两种相互冲突的知觉之间的感知转换过程中被激活。然而，这些研究并没有提供关于因果关系的信息，即活动是报告感知变化的结果还是原因。在这里，我们使用功能磁共振成像在 15 名受试者的双眼竞争期间单独定位参与知觉转换的四个顶叶区域，并随后使用 2 Hz 重复经颅磁刺激（TMS）干扰它们的神经处理和控制部位的神经处理。我们发现，TMS 对一个部位（右侧顶内沟）的刺激延长了稳定知觉的时间。此外，IPS 中血氧水平依赖信号的偏侧化程度越高，TMS 的影响就越偏侧化。偏侧化在个体之间差异很大，存在右半球偏向。对照重播实验排除了 TMS 对任务表现、反应时间或眨眼的非特异性影响。因此，我们的结果证明了 IPS 正常功能对竞争中知觉连续性的因果、不稳定和个体偏侧化的影响。这与 IPS 在知觉选择中的作用是一致的，将其在竞争知觉中的作用与在注意力中的作用联系起来。
