Langemann Ulrike, Klump Georg M
Institut für Biologie und Umweltwissenschaften, Fakultät V, Universität Oldenburg, Carl von Ossietzky Str. 9-11, D-26129 Oldenburg, Germany.
Eur J Neurosci. 2007 Oct;26(7):1969-78. doi: 10.1111/j.1460-9568.2007.05804.x.
Most signals from the auditory world have temporal patterns of amplitude modulation that either emanate from the signal source or result from environmental interference (e.g. air turbulence). To investigate mechanisms associated with the segregation and processing of amplitude-modulated signals, we trained European starlings (Sturnus vulgaris) to detect a signal noise band embedded in several flanking noise bands (FBs). We manipulated the envelope correlation between the signal and FBs, the onset synchrony between signal and FBs (0 or100 ms), signal duration (60 or 400 ms) and the spectrum level of the FBs (15 or 50 dB). The lowest signal-detection thresholds were found when the envelopes of the FBs were correlated with each other but different from the signal envelope (the 'co-uncorrelated' condition). Detection thresholds were on average 7 dB higher when both the signal and the FBs had correlated envelopes (the 'all correlated' condition). Thresholds were even higher when the envelopes of all noise bands were independent (the 'all uncorrelated' condition). The difference in detection thresholds between the co-uncorrelated and the all correlated conditions is termed 'comodulation detection difference' (CDD). Differences in signal duration and masker level had significant effects on detection threshold, but not on CDD magnitudes; differences in onset synchrony had no effects. We compare data from starlings with those from previous psychoacoustic studies of humans, and discuss possible mechanisms on which these perceptual effects may rely. Our behavioural data are the reference for a companion study investigating CDD at the neuronal level of the starling [M.A. Bee et al. (2007) Eur. J. Neurosci., 26, 1979-1994].
来自听觉世界的大多数信号都具有幅度调制的时间模式，这些模式要么源自信号源，要么是由环境干扰（如空气湍流）导致的。为了研究与幅度调制信号的分离和处理相关的机制，我们训练欧洲椋鸟（家八哥）来检测嵌入在几个侧翼噪声带（FBs）中的信号噪声带。我们操纵了信号与FBs之间的包络相关性、信号与FBs之间的起始同步性（0或100毫秒）、信号持续时间（60或400毫秒）以及FBs的频谱水平（15或50分贝）。当FBs的包络相互关联但与信号包络不同时（“共同不相关”条件），发现了最低的信号检测阈值。当信号和FBs的包络都相关时（“全部相关”条件），检测阈值平均高出7分贝。当所有噪声带的包络都独立时（“全部不相关”条件），阈值甚至更高。共同不相关条件和全部相关条件之间检测阈值的差异被称为“共调制检测差异”（CDD）。信号持续时间和掩蔽水平的差异对检测阈值有显著影响，但对CDD幅度没有影响；起始同步性的差异没有影响。我们将椋鸟的数据与之前人类心理声学研究的数据进行比较，并讨论这些感知效应可能依赖的潜在机制。我们的行为数据为一项在椋鸟神经元水平上研究CDD的配套研究提供了参考[M.A. Bee等人（2007年），《欧洲神经科学杂志》，26卷，1979 - 1994页]。
