Opponent Coding of Sound Location (Azimuth) in Planum Temporale is Robust to Sound-Level Variations.
Opponent Coding of Sound Location (Azimuth) in Planum Temporale is Robust to Sound-Level Variations.
复制标题
颞平面中声音位置（方位角）的对手编码对于声级变化具有鲁棒性。
DOI：
10.1093/cercor/bhv269
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发表时间：
2016-01
期刊：
影响因子：
--
通讯作者：
Formisano E
中科院分区：
文献类型：
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作者：
Derey K;Valente G;de Gelder B;Formisano E
听觉皮质（AC）中声音定位的编码仅被部分理解。最近的电生理学研究表明，哺乳动物听觉皮层的神经元具有广泛的空间调谐和对侧半场的偏好，即声音方位的不均匀采样。此外，空间选择性随声强的增加而降低。为了适应这些发现，有人提出声音定位是由具有相反半场调谐的神经元群体的综合活动编码的（“对手通道模型”）。在这项研究中，我们利用功能性磁共振成像（fMRI）和相位编码范式研究了这种模型在人类交流中的有效性，该范式采用双耳刺激分别记录给每个参与者。在所有受试者中，我们观察到对侧方位位置的优先fMRI反应。此外，在大多数交流位置，空间调谐是广泛的，而不是水平不变的。我们通过减去双侧颞平面对侧调谐区域的活动，推导出fMRI反应的对手通道模型。这导致了声音方位位置的准确解码，不受声级变化的影响。因此，我们的数据支持对手信道编码作为一种神经机制来表示人类交流中的声学方位角。
Coding of sound location in auditory cortex (AC) is only partially understood. Recent electrophysiological research suggests that neurons in mammalian auditory cortex are characterized by broad spatial tuning and a preference for the contralateral hemifield, that is, a nonuniform sampling of sound azimuth. Additionally, spatial selectivity decreases with increasing sound intensity. To accommodate these findings, it has been proposed that sound location is encoded by the integrated activity of neuronal populations with opposite hemifield tuning (“opponent channel model”). In this study, we investigated the validity of such a model in human AC with functional magnetic resonance imaging (fMRI) and a phase-encoding paradigm employing binaural stimuli recorded individually for each participant. In all subjects, we observed preferential fMRI responses to contralateral azimuth positions. Additionally, in most AC locations, spatial tuning was broad and not level invariant. We derived an opponent channel model of the fMRI responses by subtracting the activity of contralaterally tuned regions in bilateral planum temporale. This resulted in accurate decoding of sound azimuth location, which was unaffected by changes in sound level. Our data thus support opponent channel coding as a neural mechanism for representing acoustic azimuth in human AC.