Langemann Ulrike, Klump Georg M
Institut für Biologie und Umweltwissenschaften, Fakultät V, Universität Oldenburg, Carl von Ossietzky Strasse 9-11, D-26129 Oldenburg, Germany.
Hear Res. 2006 Nov;221(1-2):26-35. doi: 10.1016/j.heares.2006.06.018. Epub 2006 Sep 14.
Psychophysical studies of simultaneous masking with human observers exhibit an asymmetry in the amount of masking that depends on the relative bandwidths of signals and maskers. For noise bands up to the bandwidth of one auditory filter, masked auditory thresholds are considerably lower when the bandwidth of the signal exceeds that of the masker compared to the reversed condition. We investigate asymmetry of masking in an animal model, that will allow to study the mechanisms associated with the asymmetry of masking effect. European starlings (Sturnus vulgaris) were trained in a Go/NoGo paradigm to report the detection of a 500 ms noise signal centred in a 700 ms noise masker. Signals and maskers with centre frequencies of 2 kHz had bandwidths of 4 Hz or 256 Hz. Thresholds for detecting the 256 Hz wide-band signal in a 4 Hz narrow-band masker were considerably lower compared to detecting the 4 Hz narrow-band signal in a 256 Hz wide masker and compared to all other conditions. The asymmetry of masking in starlings was on average 15 and 17 dB for 40 and 70 dB SPL overall masker level, respectively. Our animal model thus proved perceptual abilities similar to human subjects. The results are discussed with respect to the importance of both intensity and temporal cues for signal detection.
对人类观察者进行的同时掩蔽心理物理学研究表明，掩蔽量存在不对称性，这取决于信号和掩蔽器的相对带宽。对于带宽不超过一个听觉滤波器带宽的噪声带，当信号带宽超过掩蔽器带宽时，与相反情况相比，掩蔽听觉阈值要低得多。我们在动物模型中研究掩蔽的不对称性，这将有助于研究与掩蔽效应不对称性相关的机制。欧洲椋鸟（Sturnus vulgaris）在Go/NoGo范式中接受训练，以报告对一个以700毫秒噪声掩蔽器为中心的500毫秒噪声信号的检测。中心频率为2千赫的信号和掩蔽器的带宽分别为4赫兹或256赫兹。与在256赫兹宽带掩蔽器中检测4赫兹窄带信号以及与所有其他条件相比，在4赫兹窄带掩蔽器中检测256赫兹宽带信号的阈值要低得多。对于总掩蔽器水平为40和70分贝声压级的情况，椋鸟掩蔽的不对称性平均分别为15分贝和17分贝。因此，我们的动物模型证明了其与人类受试者相似的感知能力。我们从强度和时间线索对信号检测的重要性方面对结果进行了讨论。
