Department of Neuroscience, City University of Hong Kong, Hong Kong SAR.
Department of Neuroscience, City University of Hong Kong, Hong Kong SAR.
Hear Res. 2021 Dec;412:108357. doi: 10.1016/j.heares.2021.108357. Epub 2021 Oct 14.
Previous psychophysical studies have identified a hierarchy of time-averaged statistics which determine the identity of natural sound textures. However, it is unclear whether the neurons in the inferior colliculus (IC) are sensitive to each of these statistical features in the natural sound textures. We used 13 representative sound textures spanning the space of 3 statistics extracted from over 200 natural textures. The synthetic textures were generated by incorporating the statistical features in a step-by-step manner, in which a particular statistical feature was changed while the other statistical features remain unchanged. The extracellular activity in response to the synthetic texture stimuli was recorded in the IC of anesthetized rats. Analysis of the transient and sustained multiunit activity after each transition of statistical feature showed that the IC units were sensitive to the changes of all types of statistics, although to a varying extent. For example, we found that more neurons were sensitive to the changes in variance than that in the modulation correlations. Our results suggest that the sensitivity of the statistical features in the subcortical levels contributes to the identification and discrimination of natural sound textures.
先前的心理物理学研究已经确定了一组时间平均统计量的层次结构，这些统计量决定了自然声音纹理的身份。然而，目前尚不清楚下丘脑中的神经元是否对自然声音纹理中的每一个统计特征都敏感。我们使用了 13 种具有代表性的声音纹理，这些纹理涵盖了从 200 多种自然纹理中提取的 3 种统计量的空间。通过逐步的方式将统计特征融入到合成纹理中，从而产生合成纹理，在此过程中，在其他统计特征保持不变的情况下改变特定的统计特征。在麻醉大鼠的下丘脑中记录了对合成纹理刺激的细胞外活动。对每种统计特征变化后的瞬态和持续多单位活动的分析表明，IC 单元对所有类型的统计特征的变化都很敏感，尽管程度不同。例如，我们发现，与调制相关性的变化相比，更多的神经元对方差的变化敏感。我们的研究结果表明，在皮质下水平对统计特征的敏感性有助于自然声音纹理的识别和区分。
