The corticofugal system for hearing: recent progress.
The corticofugal system for hearing: recent progress.
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DOI：
10.1073/pnas.97.22.11807
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发表时间：
2000-10
影响因子：
11.1
通讯作者：
Nobuo Suga;Enquan Gao;Yunfeng Zhang;Xiaofeng Ma;J. F. Olsen
中科院分区：
文献类型：
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作者：
Nobuo Suga;Enquan Gao;Yunfeng Zhang;Xiaofeng Ma;J. F. Olsen
外周听觉神经元被调谐到单一频率的声音。在中枢听觉系统中，兴奋性（或促进性）和抑制性神经相互作用发生在多个层面，并产生具有尖锐水平耐受频率调谐曲线的神经元、调谐到频率以外参数的神经元、耳蜗专题（频率）图（与外周耳蜗专题图不同）和计算图。产生这些神经元反应特性的机制被认为完全是由上行听觉系统中神经元的发散和会聚投射引起的。然而，最近对离皮质（下降）听觉系统的研究表明，离皮质系统通过调节神经反应和映射来调整和改善听觉信号处理。离皮质功能至少由以下子功能组成。 （i）根据听觉经验对听觉信号处理的短期调制进行自我中心选择。自我中心选择基于与广泛的侧抑制相关的集中正反馈，由皮质神经网络与皮质系统一起介导。 (ii) 重组行为相关听觉信号处理的长期调制。重组基于以自我为中心的选择与非听觉系统的协同工作。 (iii) 基于整体兴奋性、促进性或抑制性皮质调节获得控制。以自我为中心的选择可以被视为选择性增益控制。 (iv) 塑造（甚至创造）神经元的反应特性。神经元在频率、幅度、时间和空间域中的过滤特性可以通过皮质系统来增强。调音的锐化是自我中心选择的功能之一。
Peripheral auditory neurons are tuned to single frequencies of sound. In the central auditory system, excitatory (or facilitatory) and inhibitory neural interactions take place at multiple levels and produce neurons with sharp level-tolerant frequency-tuning curves, neurons tuned to parameters other than frequency, cochleotopic (frequency) maps, which are different from the peripheral cochleotopic map, and computational maps. The mechanisms to create the response properties of these neurons have been considered to be solely caused by divergent and convergent projections of neurons in the ascending auditory system. The recent research on the corticofugal (descending) auditory system, however, indicates that the corticofugal system adjusts and improves auditory signal processing by modulating neural responses and maps. The corticofugal function consists of at least the following subfunctions. (i) Egocentric selection for short-term modulation of auditory signal processing according to auditory experience. Egocentric selection, based on focused positive feedback associated with widespread lateral inhibition, is mediated by the cortical neural net working together with the corticofugal system. (ii) Reorganization for long-term modulation of the processing of behaviorally relevant auditory signals. Reorganization is based on egocentric selection working together with nonauditory systems. (iii) Gain control based on overall excitatory, facilitatory, or inhibitory corticofugal modulation. Egocentric selection can be viewed as selective gain control. (iv) Shaping (or even creation) of response properties of neurons. Filter properties of neurons in the frequency, amplitude, time, and spatial domains can be sharpened by the corticofugal system. Sharpening of tuning is one of the functions of egocentric selection.