Department for Neuroscience, Carl von Ossietzky University Oldenburg, Oldenburg, Germany.
Adv Exp Med Biol. 2013;787:399-407. doi: 10.1007/978-1-4614-1590-9_44.
Compared to humans, Mongolian gerbils (Meriones unguiculatus) are much more sensitive at detecting mistuning of frequency components of a harmonic complex (Klinge and Klump. J Acoust Soc Am 128:280-290, 2010). One processing mechanism suggested to result in the high sensitivity involves evaluating the phase shift that gradually develops between the mistuned and the remaining components in the same or separate auditory filters. To investigate if this processing mechanism may explain the observed sensitivity, we determined the gerbils' thresholds to detect a constant phase shift in a component of a harmonic complex that is introduced without a frequency shift. The gerbils' detection thresholds for constant phase shifts were considerably lower for a high-frequency component (6,400 Hz) than for a low-frequency component (400 Hz) of a 200-Hz harmonic complex and increased with decreasing stimulus duration. Compared to the phase shifts calculated from the mistuning detection thresholds, the detection thresholds for constant phase shifts were similar to those for gradual phase shifts for the low-frequency harmonic but considerably lower for the high-frequency harmonic. A simulation of the processing of harmonic complexes by the gerbil's peripheral auditory filters when components are phase shifted shows waveform changes comparable to those assessed for mistuning detection Klinge and Klump (J Acoust Soc Am 128:280-290, 2010) and provides evidence that detection of the gradual phase shifts may underlie mistuning detection.
与人类相比，蒙古沙鼠（Meriones unguiculatus）对谐波复合音中频率成分失谐的检测更为敏感（Klinge 和 Klump，J Acoust Soc Am 128：280-290，2010）。一种被认为导致这种高灵敏度的处理机制涉及评估在相同或不同听觉滤波器中，失谐和剩余成分之间逐渐发展的相位偏移。为了研究这种处理机制是否可以解释观察到的敏感性，我们确定了沙鼠检测谐波复合音中无频率位移的成分的恒定相位偏移的阈值。沙鼠检测高频成分（6400Hz）的恒定相位偏移的阈值明显低于低频成分（400Hz），并且随着刺激持续时间的减少而增加。与失谐检测阈值计算出的相位偏移相比，高频谐波的恒定相位偏移的检测阈值与逐渐相位偏移的检测阈值相似，但低频谐波的检测阈值则低得多。当沙鼠的外围听觉滤波器对谐波复合音的成分进行相位偏移处理时，对谐波复合音的处理的模拟显示出与失谐检测中评估的波形变化相当的变化（Klinge 和 Klump，J Acoust Soc Am 128：280-290，2010），并提供了证据表明，逐渐相位偏移的检测可能是失谐检测的基础。
