Guest Daniel R, Cameron David A, Schwarz Douglas M, Leong U-Cheng, Richards Virginia M, Carney Laurel H
Department of Biomedical Engineering, University of Rochester, Rochester, New York 14620, USA.
Department of Neuroscience, University of Rochester, Rochester, New York 14620, USA.
J Acoust Soc Am. 2024 Dec 1;156(6):4303-4325. doi: 10.1121/10.0034635.
Profile-analysis experiments measure the ability to discriminate complex sounds based on patterns, or profiles, in their amplitude spectra. Studies of profile analysis have focused on normal-hearing listeners and target frequencies near 1 kHz. To provide more insight into underlying mechanisms, we studied profile analysis over a large target frequency range (0.5-4 kHz) and in listeners with both normal and elevated audiometric thresholds. We found that profile analysis degrades at high frequencies and that the effect of spacing between nearby frequency components differs with frequency. Consistent with prior reports, elevated audiometric thresholds were not associated with impaired performance when stimuli consisted of few distantly spaced frequency components. However, elevated audiometric thresholds were associated with elevated profile-analysis thresholds for stimuli composed of many closely spaced frequency components. Behavioral thresholds from listeners with and without hearing loss were predicted by decoding firing rates from simulated auditory-nerve fibers or simulated modulation-sensitive inferior-colliculus neurons. Although responses from both model stages informed some aspects of the behavioral data, only population decoding of inferior-colliculus responses accounted for the worsening of profile-analysis thresholds at high target frequencies. Collectively, these results suggest that profile analysis involves multiple non-peripheral factors, including multichannel comparisons and midbrain tuning to amplitude modulation.
轮廓分析实验测量基于复杂声音幅度谱中的模式或轮廓来辨别它们的能力。轮廓分析的研究主要集中在听力正常的听众以及接近1kHz的目标频率上。为了更深入了解潜在机制，我们在较宽的目标频率范围（0.5 - 4kHz）内以及听力阈值正常和升高的听众中研究了轮廓分析。我们发现轮廓分析在高频时会退化，并且相邻频率成分之间的间距效应随频率而不同。与先前的报告一致，当刺激由少数间隔较远的频率成分组成时，听力阈值升高与性能受损无关。然而，对于由许多紧密间隔的频率成分组成的刺激，听力阈值升高与轮廓分析阈值升高有关。通过解码模拟听觉神经纤维或模拟调制敏感的下丘神经元的放电率，可以预测有听力损失和无听力损失听众的行为阈值。虽然两个模型阶段的反应都为行为数据的某些方面提供了信息，但只有下丘反应的群体解码解释了高目标频率下轮廓分析阈值的恶化。总体而言，这些结果表明轮廓分析涉及多个非外周因素，包括多通道比较和中脑对幅度调制的调谐。
