Bradford School of Optometry and Vision Science, University of Bradford, Bradford, UK.
Exp Brain Res. 2012 May;218(3):477-85. doi: 10.1007/s00221-012-3038-3. Epub 2012 Feb 25.
Our sensory systems face a daily barrage of auditory and visual signals whose arrival times form a wide range of audiovisual asynchronies. These temporal relationships constitute an important metric for the nervous system when surmising which signals originate from common external events. Internal consistency is known to be aided by sensory adaptation: repeated exposure to consistent asynchrony brings perceived arrival times closer to simultaneity. However, given the diverse nature of our audiovisual environment, functionally useful adaptation would need to be constrained to signals that were generated together. In the current study, we investigate the role of two potential constraining factors: spatial and contextual correspondence. By employing an experimental design that allows independent control of both factors, we show that observers are able to simultaneously adapt to two opposing temporal relationships, provided they are segregated in space. No such recalibration was observed when spatial segregation was replaced by contextual stimulus features (in this case, pitch and spatial frequency). These effects provide support for dedicated asynchrony mechanisms that interact with spatially selective mechanisms early in visual and auditory sensory pathways.
我们的感觉系统每天都会接收到大量的听觉和视觉信号,这些信号的到达时间形成了广泛的视听时滞。这些时间关系是神经系统推断哪些信号来自共同的外部事件的一个重要指标。人们知道,感觉适应有助于内部一致性:重复暴露在一致的时滞中会使感知的到达时间更接近同时性。然而,考虑到我们视听环境的多样性,功能上有用的适应需要局限于一起产生的信号。在当前的研究中,我们研究了两个潜在的约束因素的作用:空间和上下文对应。通过采用一种允许独立控制这两个因素的实验设计,我们表明,观察者能够同时适应两种相反的时间关系,只要它们在空间上是分开的。当空间分离被上下文刺激特征(在这种情况下,音调和空间频率)取代时,就不会观察到这种重新校准。这些效应为专门的时滞机制提供了支持,这些机制与视觉和听觉感觉通路早期的空间选择性机制相互作用。