Department of Biomedical Engineering, The City College of the City University of New York, Steinman Hall, Room T-401, Convent Avenue, 140th Street, New York, New York 10031, USA.
J Acoust Soc Am. 2010 Feb;127(2):970-6. doi: 10.1121/1.3277156.
Neuronal gain adaptation has been proposed as the underlying mechanism leading to the perception of phantom sounds such as Zwicker tones and tinnitus. In this gain-adaptation theory, cochlear compression plays a significant role with weaker compression leading to stronger phantom percepts. The specific aim of this study was to find a link between the strength of neuronal gain adaptation and cochlear compression. Compression was assessed using distortion product otoacoustic emissions (DPOAEs). Gain adaptation is hypothesized to manifest itself in the sensitization observed for the detection of masked tones when preceded by notched noise. Perceptual thresholds for pure tones in notched noise were measured at multiple frequencies following various priming signals. The observed sensitization was larger than expected from the combined effect of the various maskers. However, there was no link between sensitization and compression. Instead, across subjects, stronger sensitization correlated with stronger DPOAEs evoked by low-level primaries. In addition, growth of DPOAEs correlated reliably with perceptual thresholds across frequencies within subjects. Together, the data suggest that short-term dynamic adaptation leading to perceptual sensitization is the result of an active process mediated by the outer hair cells, which are thought to modulate the gain of the cochlear amplifier via efferent feedback.
神经增益适应被认为是导致幻听（如 Zwicker 音和耳鸣）感知的潜在机制。在这种增益适应理论中，耳蜗压缩起着重要作用，较弱的压缩会导致更强的幻听感知。本研究的具体目的是在神经元增益适应的强度和耳蜗压缩之间找到联系。使用畸变产物耳声发射（DPOAE）评估压缩。增益适应被假设表现在掩蔽音调检测中观察到的敏化，当被带缺口噪声预先刺激时。在多种激发信号后，在多个频率下测量纯音在带缺口噪声中的感知阈值。观察到的敏化比各种掩蔽器的综合效应所预期的要大。然而，敏化与压缩之间没有联系。相反，在不同的被试中，更强的敏化与由低水平原发音引起的更强的 DPOAE 相关。此外，DPOAE 的增长与被试内的感知阈值在各个频率上可靠相关。综上所述，数据表明，导致感知敏化的短期动态适应是由外毛细胞介导的主动过程的结果，外毛细胞被认为通过传出反馈调节耳蜗放大器的增益。
