Single neurons in the frog inferior colliculus exhibit direction-dependent frequency selectivity to isointensity tone bursts.
Single neurons in the frog inferior colliculus exhibit direction-dependent frequency selectivity to isointensity tone bursts.
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DOI：
10.1121/1.408677
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发表时间：
1994-04
期刊：
影响因子：
--
通讯作者：
J. Xu;D. Gooler;A. Feng
中科院分区：
文献类型：
--
作者：
J. Xu;D. Gooler;A. Feng
通过测量下丘(IC)神经元对不同声级自由场扬声器发出的短音的等强度频率响应(FRS)，研究了声方向对下丘神经元频率选择性的影响。扬声器在额场中以0度仰角旋转180度方位角(从对侧90度或C90度旋转至同侧90度或I90度)。在每个频率下，为了评估反应随声音方向变化的幅度，比较了在方位角和在C90度获得的平均棘波计数。大多数IC神经元的FR(75/83或90%)具有方向依赖性。对于这些神经元中的大多数，当声音来自同侧方位时，FRS的带宽较窄。值得注意的是，随着声方位角的变化，这些FRS的某些部分显示出非常明显的形状变化，而相同FRS的其他部分基本上保持不变。这些与FR的受限部分相关的窄带变化也被具有方向相关的频率-阈值特征的神经元所表现(Gooler等人，1993)。此外，FRS中最频繁的方向相关变化发生在单位最佳兴奋频率附近的一个狭窄频带内。
The effects of sound direction on frequency selectivity of inferior colliculus (IC) neurons were investigated by measuring the neuron's isointensity frequency responses (FRs) to tone bursts emanating from a free-field loudspeaker at several sound levels. The loudspeaker was rotated across the frontal field at 0 degrees elevation through 180 degrees of azimuth (from contralateral 90 degrees or C90 degrees to ipsilateral 90 degrees or I90 degrees). At each frequency, to assess the magnitude of response change with sound direction, the mean spike count obtained at an azimuth was compared to that at C90 degrees. The FR of most IC neurons (75/83 or 90%) was direction dependent. For most of these neurons, bandwidths of FRs were narrower when sounds originated from ipsilateral azimuths. Remarkably, with a change in sound azimuth, some segments of these FRs showed very distinct changes in shape, while other portions of the same FRs remained essentially unchanged. These narrow-band changes associated with restricted portions of the FR, were also exhibited by neurons with direction-dependent frequency-threshold characteristics (Gooler et al., 1993). Additionally, the most frequent direction-dependent change in the FRs occurred in a narrow frequency band around the units' best excitatory frequency.