Stimulus context affects auditory cortical responses to changes in interaural correlation
Stimulus context affects auditory cortical responses to changes in interaural correlation
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DOI：
10.1152/jn.00359.2007
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发表时间：
2007-07-01
影响因子：
2.5
通讯作者：
Simon, Jonathan Z.
中科院分区：
文献类型：
--
作者：
Chait, Maria;Poeppel, David;Simon, Jonathan Z.
我们使用脑磁图来研究人类听觉皮层处理耳间相关性（IAC）的变化。我们研究了两种类型的宽带噪声刺激从相关（双耳相同的信号）到不相关（双耳不同的信号）或反之亦然的过渡：CHANGE信号包含一个IAC变化（或无）和ALT信号以恒定的速率在相关和不相关之间交替。相关的过渡，从相关到不相关或反之亦然，在两种刺激条件下是物理上相同的，但听觉皮层反应模式有很大的不同。CHANGE刺激在其时间动态和磁场形态中表现出响应不对称性，根据变化的方向。不同的领域模式表明参与单独的神经基板的处理，和不同的lavelets暗示不同的时间整合窗口。与此相反，在ALT刺激的变化的反应的时间动态没有显着不同的方向变化。值得注意的是，ALT刺激中的不相关到相关过渡显示出比CHANGE刺激中的相同过渡早90 ms的第一偏转，并且具有相反的磁场分布。这一发现表明，早在50毫秒后的IAC过渡的发病，一个给定的物理变化的处理差异取决于刺激上下文。因此，即使是早期的皮层激活不能独立于实验中使用的特定的长期刺激上下文来解释。
We use magnetoencephalography to study human auditory cortical processing of changes in interaural correlation (IAC). We studied transitions from correlated (identical signals at the 2 ears) to uncorrelated (different signals at the 2 ears) or vice versa for two types of wide-band noise stimuli: CHANGE signals contained a single IAC change (or none) and ALT signals alternated between correlated and uncorrelated at a constant rate. The relevant transitions, from correlated to uncorrelated or vice versa, are physically identical in both stimulus conditions, but auditory cortical response patterns differed substantially. CHANGE stimuli exhibited a response asymmetry in their temporal dynamics and magnetic field morphology according to the direction of change. Distinct field patterns indicate the involvement of separate neural substrates for processing, and distinct latencies are suggestive of different temporal integration windows. In contrast, the temporal dynamics of responses to change in the ALT stimuli did not differ substantially according to the direction of change. Notably, the uncorrelated-to-correlated transition in the ALT stimuli showed a first deflection similar to 90 ms earlier than for the same transition in the CHANGE stimuli and with an opposite magnetic field distribution. This finding suggests that as early as 50 ms after the onset of an IAC transition, a given physical change is processed differentially depending on stimulus context. Consequently, even early cortical activation cannot be interpreted independently of the specific long-term stimulus context used in the experiment.