BINAURAL INTERACTION IN HIGH-FREQUENCY NEURONS IN INFERIOR COLLICULUS OF THE CAT - EFFECTS OF VARIATIONS IN SOUND PRESSURE LEVEL ON SENSITIVITY TO INTERAURAL INTENSITY DIFFERENCES
BINAURAL INTERACTION IN HIGH-FREQUENCY NEURONS IN INFERIOR COLLICULUS OF THE CAT - EFFECTS OF VARIATIONS IN SOUND PRESSURE LEVEL ON SENSITIVITY TO INTERAURAL INTENSITY DIFFERENCES
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DOI：
10.1152/jn.1990.63.3.570
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发表时间：
1990-03-01
影响因子：
2.5
通讯作者：
GAGO, G
中科院分区：
文献类型：
--
作者：
IRVINE, DRF;GAGO, G
1. 耳间强度差（IID）是神经元群编码高频声音方位角位置的主要双耳线索，其模型的开发需要了解单个神经元的 IID 敏感性在多大程度上不随声压级（SPL）和其他刺激参数的变化而变化。为了检查该组织，从麻醉猫下丘 (ICC) 中央核中特征频率 (CF) 大于 3 kHz 的神经元大样本 (n = 458) 中获取记录。在接受兴奋性对侧输入和抑制性或混合抑制/促进性同侧输入（EI 神经元）的神经元中检查了对 IID 的敏感性以及 SPL 变化对此敏感性的影响。 2.发现EI神经元IID敏感性的形式以及SPL变化对该敏感性的影响部分是由神经元单耳对侧刺激的速率-强度函数的特征决定的，因此获得了91个神经元的详细速率-强度函数。许多 ICC 神经元具有非单调速率-强度函数，其比例根据所采用的非单调性标准进行分类。 3.使用一种生成 IID 的方法，保持两耳刺激的平均双耳强度 (ABI) 恒定，以一种或多种强度获得 90 个神经元的 CF 音调刺激的 IID 灵敏度函数。在为每个单元获得函数的标准 ABI 范围内，大多数 EI 神经元 (72%) 具有单调（S 形）或近单调 IID 敏感性函数。其余的具有非单调（峰值）IID 敏感性函数，这可归因于混合的抑制性和促进性同侧影响，或归因于同侧刺激的影响叠加在兴奋性耳朵强度变化的非单调影响上。 4.在两个或多个ABI（大多数情况下为3-5）下检查40个被分类为在标准ABI范围内具有单调或近单调功能的神经元和7个被分类为非单调的神经元的IID敏感性。对于一小部分具有单调 IID 敏感函数的神经元，函数的形式随着 ABI 的变化相对不变。在那些 IID 敏感性函数的形式随 ABI 变化而变化的单调神经元中，最常见的变化类型是，随着 ABI 的增加，函数的倾斜部分的位置系统性地向有利于同侧耳朵的较大 IID 的方向移动。（摘要截断为 400 字）
1. Development of models of the manner in which interaural intensity differences (IIDs), the major binaural cue for the azimuthal location of high-frequency sounds, are coded by populations of neurons requires knowledge of the extent to which the IID sensitivity of individual neurons is invariant with changes in sound pressure level (SPL) and other stimulus parameters. To examine this tissue, recordings were obtained from a large sample (n = 458) of neurons with characteristic frequency (CF) greater than 3 kHz in the central nucleus of the inferior colliculus (ICC) of anesthetized cats. The sensitivity to IIDs and the effects of changes in SPL on this sensitivity were examined in neurons receiving excitatory contralateral input and inhibitory or mixed inhibitory/facilitatory ipsilateral input (EI neurons). 2. The form of an EI neuron's IID sensitivity and the effects of changes in SPL on that sensitivity were found to be determined in part by the characteristics of the neuron's rate-intensity function for monaural contralateral stimulation, and detailed rate-intensity functions were therefore obtained for 91 neurons. Many ICC neurons have nonmonotonic rate-intensity functions, the proportion so classified depending on the criterion of nonmonotonicity employed. 3. IID sensitivity functions for CF tonal stimuli were obtained at one or more intensities for 90 neurons, using a method of generating IIDs that kept the average binaural intensity (ABI) of the stimuli at the two ears constant. In the standard ABI range in which a function was obtained for each unit, the majority of EI neurons (72%) had monotonic (sigmoidal) or near-monotonic IID sensitivity functions. The remainder had nonmonotonic (peaked) IID sensitivity functions, which were attributable either to mixed inhibitory and facilitatory ipsilateral influences or to the fact that the effects of ipsilateral stimulation were superimposed on nonmonotonic effects of changes in intensity at the excitatory ear. 4. IID sensitivity was examined at two or more ABIs (3-5 in most cases) for 40 neurons classified as having monotonic or near-monotonic functions in the standard ABI range and for 7 neurons classified as nonmonotonic. For a small proportion of neurons with monotonic IID sensitivity functions, the form of the function was relatively invariant with changes in ABI. In those monotonic neurons in which the form of the IID sensitivity function varied with changes in ABI, the most common type of variation was that the position of the sloping portion of the function shifted systematically in the direction of larger IIDs favoring the ipsilateral ear as ABI increased.(ABSTRACT TRUNCATED AT 400 WORDS)