Sensitivity of auditory cortical neurons to the locations of leading and lagging sounds.
Sensitivity of auditory cortical neurons to the locations of leading and lagging sounds.
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DOI：
10.1152/jn.00580.2004
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发表时间：
2005-08
影响因子：
2.5
通讯作者：
B. Mickey;J. C. Middlebrooks
中科院分区：
文献类型：
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作者：
B. Mickey;J. C. Middlebrooks
我们记录了麻醉猫听觉皮质（A1、A2和PAF区域）中的单位活动，同时呈现具有不同位置和刺激间延迟（ISD）的成对滴答声。在人类听众中，这样的声音引起优先效应，其中滞后声音的定位在ISD小于10 ms时受损。在本研究中，神经元通常以短暂的尖峰脉冲响应领先刺激，随后是持续100-200 ms的抑制。在ISD为20 ms时，听众报告明显的滞后声音，只有12%的单位表现出离散的滞后反应。持久的抑制被发现在所有采样的皮质领域，所有领先和落后的位置，并在所有的声音水平。来自清醒猫的记录证实了在没有麻醉的情况下这种持久的抑制，尽管在清醒状态下从抑制中恢复得更快。尽管在1-20 ms的延迟时缺乏离散滞后响应，但40%的单位的尖峰模式随ISD系统地变化，这表明许多神经元在其时间放电模式中隐含地表示滞后声音，而不是明确地表示离散响应。我们估计的位置相关的信息传输的尖峰模式在延迟1-16毫秒的条件下，我们只改变了领先的位置或滞后的位置。与人类的心理物理结果一致，在所有ISDs中，关于领先位置的信息传输都很高。然而，与收听者不同的是，即使在12-16 ms的ISD下，关于滞后位置的信息的传输仍然很低。
We recorded unit activity in the auditory cortex (fields A1, A2, and PAF) of anesthetized cats while presenting paired clicks with variable locations and interstimulus delays (ISDs). In human listeners, such sounds elicit the precedence effect, in which localization of the lagging sound is impaired at ISDs less, similar10 ms. In the present study, neurons typically responded to the leading stimulus with a brief burst of spikes, followed by suppression lasting 100-200 ms. At an ISD of 20 ms, at which listeners report a distinct lagging sound, only 12% of units showed discrete lagging responses. Long-lasting suppression was found in all sampled cortical fields, for all leading and lagging locations, and at all sound levels. Recordings from awake cats confirmed this long-lasting suppression in the absence of anesthesia, although recovery from suppression was faster in the awake state. Despite the lack of discrete lagging responses at delays of 1-20 ms, the spike patterns of 40% of units varied systematically with ISD, suggesting that many neurons represent lagging sounds implicitly in their temporal firing patterns rather than explicitly in discrete responses. We estimated the amount of location-related information transmitted by spike patterns at delays of 1-16 ms under conditions in which we varied only the leading location or only the lagging location. Consistent with human psychophysical results, transmission of information about the leading location was high at all ISDs. Unlike listeners, however, transmission of information about the lagging location remained low, even at ISDs of 12-16 ms.