Representations of Pitch and Timbre Variation in Human Auditory Cortex
Representations of Pitch and Timbre Variation in Human Auditory Cortex
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DOI：
10.1523/jneurosci.2336-16.2016
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发表时间：
2017-02-01
影响因子：
5.3
通讯作者：
Oxenham, Andrew J.
中科院分区：
文献类型：
--
作者：
Allen, Emily J.;Burton, Philip C.;Oxenham, Andrew J.
音高和音色是听觉感知的两个主要维度，但它们在人脑中的表现方式仍然是一个有争议的问题。一些关于听觉皮层处理的动物研究提出了模块化处理，不同的大脑区域优先编码音高或音色，而其他研究则提出了同一群神经元中不同属性的分布式代码。这项研究测试了音调和音色的变化是否会引起人类颞叶不同区域的活动。听众听到的声音序列在基频（引起音高的变化）或频谱质心（引起亮度的变化，音色的一个重要属性）上都有变化，每个序列中的音高或音色变化程度都被参数化处理。听觉皮层的BOLD反应随各知觉维度的序列方差沿着增加而增加。在单变量分析水平上，对音高或音色变化最敏感的皮层区域的空间范围、区域和偏侧性在很大程度上是重叠的。然而，在大多数受试者中，在个体水平上，使用多体素模式分析，响应音高或音色变化的激活模式是可辨别的，这表明在人类听觉皮层的两个维度的双边分布编码。
Pitch and timbre are two primary dimensions of auditory perception, but how they are represented in the human brain remains a matter of contention. Some animal studies of auditory cortical processing have suggested modular processing, with different brain regions preferentially coding for pitch or timbre, whereas other studies have suggested a distributed code for different attributes across the same population of neurons. This study tested whether variations in pitch and timbre elicit activity in distinct regions of the human temporal lobes. Listeners were presented with sequences of sounds that varied in either fundamental frequency (eliciting changes in pitch) or spectral centroid (eliciting changes in brightness, an important attribute of timbre), with the degree of pitch or timbre variation in each sequence parametrically manipulated. The BOLD responses from auditory cortex increased with increasing sequence variance along each perceptual dimension. The spatial extent, region, and laterality of the cortical regions most responsive to variations in pitch or timbre at the univariate level of analysis were largely overlapping. However, patterns of activation in response to pitch or timbre variations were discriminable in most subjects at an individual level using multivoxel pattern analysis, suggesting a distributed coding of the two dimensions bilaterally in human auditory cortex.