Department of Psychology, University of Canterbury, Christchurch, New Zealand.
Brain Res. 2009 Dec 11;1305:96-107. doi: 10.1016/j.brainres.2009.09.080. Epub 2009 Sep 25.
To understand the brain areas associated with visual awareness and their anatomical interconnections, we studied binocular rivalry with functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI). Binocular rivalry occurs when one image is viewed by one eye and a different image by the other; it is experienced as perceptual alternations between the two images. Our first experiment addressed problems with a popular comparison condition, namely permanent suppression, by comparing rivalry with binocular fusion instead. We found an increased fMRI signal in right frontal, parietal, and occipital regions during rivalry viewing. The pattern of neural activity differed from findings of permanent suppression comparisons, except for adjacent activity in the right superior parietal lobule. This location was near fMRI signal changes related to reported rivalry alternations in our second experiment, indicating that neighbouring areas in the right parietal cortex may be involved in different components of rivalry. In our second experiment, we used probabilistic tractography to detect white matter fibres between right-hemispheric areas that showed event-related fMRI signal changes time-locked to reported perceptual alternations during rivalry viewing. Most of these functionally defined areas were linked by probabilistic fibre tracts, some of which followed long-distance connections such as the inferior occipitofrontal fasciculus. Corresponding anatomical pathways might mediate communication within the functional network associated with changes in conscious perception during binocular rivalry.
为了理解与视觉意识相关的大脑区域及其解剖学连接，我们使用功能磁共振成像（fMRI）和弥散张量成像（DTI）研究了双眼竞争。当一只眼睛看到一个图像，而另一只眼睛看到不同的图像时，就会发生双眼竞争；人们会体验到这两个图像之间的知觉交替。我们的第一个实验通过将竞争与双眼融合进行比较，解决了流行的比较条件（即永久性抑制）所存在的问题。我们发现，在竞争观看期间，右侧额、顶和枕叶区域的 fMRI 信号增加。除了右侧顶叶上回相邻的活动外，这种神经活动模式与永久性抑制比较的发现不同。该位置靠近我们第二个实验中与报告的竞争交替相关的 fMRI 信号变化，表明右侧顶叶皮层的相邻区域可能参与了竞争的不同成分。在我们的第二个实验中，我们使用概率追踪来检测右侧半球区域之间的白质纤维，这些区域的 fMRI 信号变化与报告的竞争观看期间的知觉交替时间锁定。这些功能定义区域中的大多数通过概率纤维束连接，其中一些遵循长距离连接，如下枕额束。相应的解剖途径可能介导双眼竞争期间意识知觉变化相关的功能网络内的通信。
