Zhang W, Salvi R J, Saunders S S
Hearing Research Laboratory, SUNY University, Buffalo 14214.
Hear Res. 1990 Jul;46(3):181-200. doi: 10.1016/0378-5955(90)90001-6.
The neural correlates of gap detection were examined in a population of single auditory nerve fibers in the chinchilla. Acoustic stimuli consisted of 120 ms noise bursts (30-80 dB SPL) which contained silent intervals (gaps: 1, 2, 3, 4,5, 6 and 10 ms) at the midpoint. The neural response to the gap was quantified by the modulation index, (MAX-MIN)/AVE, which accounts for the steady state discharge rate before the gap (AVE), the minimum firing rate during the gap (MIN), and the maximum firing rate after the gap (MAX). In general, the modulation index increased as a function of gap width and stimulus level. Furthermore, there was a positive correlation between the modulation index and the characteristic frequency of the fiber. To estimate how detection could be based on the neuronal response, a criterion-free measure, analogous to d'. was calculated using z-scores obtained from the distributions of modulation index values collected before and during the gap and used to predict percent correct values for chinchilla psychophysical studies. The values increased with gap duration in a sigmoidal manner much like the psychometric functions in the chinchilla. In general, the neural gap thresholds obtained approximated those obtained psychophysically, although they were less affected by stimulus level.
在灰鼠的一群单根听神经纤维中研究了间隙检测的神经关联。声学刺激由120毫秒的噪声脉冲串（30 - 80分贝声压级）组成，这些脉冲串在中点处包含静音间隔（间隙：1、2、3、4、5、6和10毫秒）。对间隙的神经反应通过调制指数（MAX - MIN）/AVE进行量化，该指数考虑了间隙前的稳态放电率（AVE）、间隙期间的最小放电率（MIN）以及间隙后的最大放电率（MAX）。一般来说，调制指数随间隙宽度和刺激水平的增加而增加。此外，调制指数与纤维的特征频率之间存在正相关。为了估计检测如何基于神经元反应，使用从间隙前和间隙期间收集的调制指数值分布中获得的z分数计算了一种类似于d'的无标准测量方法，并用于预测灰鼠心理物理学研究的正确百分比值。这些值以S形方式随间隙持续时间增加，非常类似于灰鼠的心理测量函数。一般来说，获得的神经间隙阈值与通过心理物理学获得的阈值近似，尽管它们受刺激水平的影响较小。
