Effects of interaural time delays of noise stimuli on low-frequency cells in the cat's inferior colliculus. I. Responses to wideband noise.
Effects of interaural time delays of noise stimuli on low-frequency cells in the cat's inferior colliculus. I. Responses to wideband noise.
复制标题
噪声刺激的耳间时间延迟对猫下丘低频细胞的影响。
DOI：
10.1152/jn.1986.55.2.280
复制
发表时间：
1986
影响因子：
2.5
通讯作者：
Irvine,DR
中科院分区：
文献类型：
--
作者：
Yin,TC;Chan,JC;Irvine,DR
我们研究了猫下丘中央核（ICC）低频神经元对耳间延迟的宽带噪声刺激的反应。刺激是以60- 4，000 Hz的标称带宽数字生成的伪随机噪声信号。我们还比较了噪声的反应与纯音的耳间相位差。我们研究了144个特征频率低于2.5 kHz的神经元。百分之八十五（85%）的这些都是敏感的变化，在两个耳间的时间差（ITDs）的噪音和纯音的耳间相位差，只有2%的敏感的刺激，但不是另一个，其余的是不敏感的两个刺激。对于大多数细胞的放电率调制在一个近似的周期性的方式ITD的宽带噪声刺激的变化。最大尖峰计数经常出现在ITD接近零的时候，并且循环的性质有相当大的变化，尽管它通常在ITD大于+/-4，000微秒时消失。中央峰的位置通常（65%）在+/- 400微秒的生理相关范围内，并且大多数（80%）发生在正ITD处，这对应于同侧刺激的延迟。在一般情况下，响应的形状不受阈值以上的刺激水平的变化。只要相同的噪音传递到双耳，反应对所使用的特定噪音刺激不敏感。当不相关的噪音传递到两耳，有没有ITD的敏感性。复合曲线计算的线性总和的响应ITD的纯音在频率间隔相等的时间间隔在每个细胞的响应区域。复合曲线的形状类似于同一细胞对宽带噪声刺激ITD的反应。这两个函数的中心峰的位置高度相关（r = 0.91，斜率= 0.97）。从音调响应计算的特征延迟和特征相位的值被发现是噪声延迟曲线的形状的良好指标。接近零的特征相位（CP）与关于中心峰对称的噪声延迟曲线相关联，接近0.5周期的CP与关于谷对称的CP相关联，而0和0.5之间或0.5和1.0之间的CP具有噪声延迟曲线，该噪声延迟曲线分别在中心峰的左侧或右侧不对称地具有突出的谷。（400字处截断摘要）
We examined the responses of low-frequency neurons in the central nucleus of the inferior colliculus (ICC) of the cat to interaurally delayed, wideband noise stimuli. The stimuli were pseudorandom noise signals that were generated digitally with a nominal bandwidth of 60-4,000 Hz. We also compared the responses to noise with those obtained from interaural phase differences of pure tones. We studied 144 neurons with characteristic frequencies below 2.5 kHz. Eighty-five percent (85%) of these were sensitive to changes in both interaural time differences (ITDs) of noise and interaural phase differences of pure tones, only 2% were sensitive to one stimulus but not the other, and the remainder were insensitive to both stimuli. For most cells the discharge rate was modulated in an approximately cyclic fashion by changes in ITDs of the wideband noise stimuli. The maximal spike counts often occurred near zero ITD, and there was considerable variability in the nature of the cycling, though it usually disappeared for ITDs greater than +/- 4,000 microseconds. The position of the central peak was usually (65%) within the physiologically relevant range of +/- 400 microseconds, and most (80%) occurred at positive ITDs, which corresponded to delays to the ipsilateral stimulus. In general, the shapes of the responses were not affected by changes in stimulus level above threshold. As long as identical noises were delivered to both ears, the responses were not sensitive to the particular noise stimulus used. When uncorrelated noises were delivered to the two ears, there was no sensitivity to ITDs. Composite curves were computed by linear summation of the responses to ITDs of pure tones at frequencies spaced at equal intervals throughout each cell's response area. The shapes of composite curves were similar to the responses of the same cell to ITDs of wideband noise stimuli. The positions of the central peaks of these two functions were highly correlated (r = 0.91, slope = 0.97). The values of characteristic delay and characteristic phase computed from the tonal responses were found to be good indicators of the shapes of the noise delay curves. Characteristic phases (CPs) near zero were associated with noise delay curves symmetric about the central peak, CPs near 0.5 cycles with those symmetric about the trough, while CPs between 0 and 0.5 or between 0.5 and 1.0 had noise delay curves that were asymmetric with a prominent trough to the left or right, respectively, of the central peak.(ABSTRACT TRUNCATED AT 400 WORDS)