Sensitivity to interaural correlation of single neurons in the inferior colliculus of guinea pigs
Sensitivity to interaural correlation of single neurons in the inferior colliculus of guinea pigs
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DOI：
10.1007/s10162-005-0005-8
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发表时间：
2005-09-01
影响因子：
2.4
通讯作者：
Palmer, AR
中科院分区：
文献类型：
--
作者：
Shackleton, TM;Arnott, RH;Palmer, AR
研究了脲麻醉豚鼠下丘单个神经元对50 ms窄带或宽带噪声爆发的耳间相关性变化的敏感性。采用两种方法测量率与耳间相关函数（rICFs）。这些方法以不同的方式补偿具有相同预期相关性的符号之间的内部相关性的固有方差。所有ricf的形状都可以用幂函数来描述，从而可以用两个参数来概括它们。大多数ricf最适合小于2的次幂，这表明它们只是轻微的非线性。然而，有几个拟合函数的幂为3-6，表明有明显的曲率。模拟结果表明，大多数rICFs的非线性可以用单耳转导阶段来解释；然而，一些功率大于2的ricf要么需要多个输入到符合检测器，要么需要在模型中包含额外的非线性。在参考相关性为- 1,0和+1时，通过对每个相关性处尖峰计数分布的受试者工作特征（ROC）分析估计识别阈值。阈值跨越了整个可能的范围，从最小的0.1到最大的2。阈值一般最高，参考相关性为-1，中间，参考相关性为0，最低，参考相关性为+1。坡度最陡的ricf的阈值最低，但阈值与峰值率方差不强相关。最低的阈值是使用窄带噪声来补偿内部延迟的，但它们仍然是使用类似刺激测量的人类心理物理阈值的三倍。数据表明，与纯音间时差不同，群体测量的歧视需要考虑行为间相关歧视表现。
Sensitivity to changes in the interaural correlation of 50-ms bursts of narrowband or broadband noise was measured in single neurons in the inferior colliculus of urethane-anaesthetized guinea pigs. Rate vs. interaural correlation functions (rICFs) were measured using two methods. These methods compensated in different ways for the inherent variance in interaural correlation between tokens with the same expected correlation. The shape of all rICFs could be best described by power functions allowing them to be summarized by two parameters. Most rICFs were best fit by a power below 2, indicating that they were only slightly nonlinear. However, there were a few fitted functions that had a power of 3-6, indicating marked curvature. Modeling results indicate that the nonlinearity of the majority of rICFs was explicable in terms of the monaural transduction stages; however, some of the rICFs with power greater than 2 require either multiple inputs to the coincidence detector or additional nonlinearities to be included in the model. Discrimination thresholds were estimated at reference correlations of -1, 0, and +1 using receiver operating characteristic (ROC) analysis of the spike-count distribution at each correlation. Thresholds spanned the full possible range, from a minimum of 0.1 to the maximum possible of 2. Thresholds were generally highest with a reference correlation of -1, intermediate with a reference of 0, and lowest with a reference correlation of +1. Thresholds were lowest for the most steeply sloped rICFs, but thresholds were not strongly correlated to the spike rate variance. The lowest thresholds occurred using narrowband noise that was compensated for internal delays, but they were still about three times larger than human psychophysical thresholds measured using similar stimuli. The data suggest that, unlike pure tone interaural time difference, discrimination of a population measure is required to account for behavioral interaural correlation discrimination performance.