Cusack Rhodri
MRC Cognition and Brain Sciences Unit, Cambridge, UK.
J Cogn Neurosci. 2005 Apr;17(4):641-51. doi: 10.1162/0898929053467541.
The structuring of the sensory scene (perceptual organization) profoundly affects what we perceive, and is of increasing clinical interest. In both vision and audition, many cues have been identified that influence perceptual organization, but only a little is known about its neural basis. Previous studies have suggested that auditory cortex may play a role in auditory perceptual organization (also called auditory stream segregation). However, these studies were limited in that they just examined auditory cortex and that the stimuli they used to generate different organizations had different physical characteristics, which per se may have led to the differences in neural response. In the current study, functional magnetic resonance imaging was used to test for an effect of perceptual organization across the whole brain. To avoid confounding physical changes to the stimuli with differences in perceptual organization, we exploited an ambiguous auditory figure that is sometimes perceived as a single auditory stream and sometimes as two streams. We found that regions in the intraparietal sulcus (IPS ) showed greater activity when 2 streams were perceived rather than 1. The specific involvement of this region in perceptual organization is exciting, as there is a growing literature that suggests a role for the IPS in binding in vision, touch, and cross-modally. This evidence is discussed, and a general role proposed for regions of the IPS in structuring sensory input.
感觉场景的构建（知觉组织）深刻影响着我们的感知，并且在临床上越来越受到关注。在视觉和听觉方面，已经发现了许多影响知觉组织的线索，但对于其神经基础却知之甚少。先前的研究表明，听觉皮层可能在听觉知觉组织（也称为听觉流分离）中发挥作用。然而，这些研究存在局限性，它们仅检查了听觉皮层，并且用于产生不同组织的刺激具有不同的物理特征，这些物理特征本身可能导致神经反应的差异。在当前的研究中，功能磁共振成像被用于测试整个大脑中知觉组织的影响。为了避免将刺激的物理变化与知觉组织的差异混淆，我们利用了一个模棱两可的听觉图形，它有时被感知为一个单一的听觉流，有时被感知为两个流。我们发现，当被感知为两个流而不是一个流时，顶内沟（IPS）区域显示出更大的活动。该区域在知觉组织中的特定参与令人兴奋，因为越来越多的文献表明IPS在视觉、触觉和跨模态绑定中发挥作用。本文讨论了这一证据，并提出了IPS区域在构建感觉输入方面的一般作用。
