Wiegrebe L, Kössl M, Schmidt S
Zoologisches Institut, Universität, Munich, Germany.
Hear Res. 1996 Oct;100(1-2):171-80. doi: 10.1016/0378-5955(96)00111-6.
Auditory enhancement describes an improvement in the detection of a tonal signal in a broad-band masker with a spectral gap at the signal frequency if the signal is delayed in its onset relative to the masker. This auditory enhancement may be based on an increase of the effective signal level instead of a decline in the effective masker level. In order to evaluate whether this signal enhancement also exists at the threshold of hearing, we measured the absolute threshold for pure-tone pulses of different frequencies with and without preceding band-rejected noise. Such noise also causes the sensation of the Zwicker tone-a faint pure tone lasting for a few seconds immediately after the noise presentation. The pitch of this sensation is a complex function of the noise parameters but always lies at a frequency within the rejected band. During the Zwicker tone sensation, auditory sensitivity for tone pulses at frequencies adjacent to the Zwicker tone was improved by up to 13 dB instead of being reduced which might be expected due to the presence of the simultaneously audible Zwicker tone. The failure to influence this threshold shift with low-frequency tones and measurements of the ear's acoustical response indicate that this threshold improvement may be produced through neuronal disinhibition rather than through a release from mechanical suppression in the cochlea.
听觉增强描述的是，如果信号的起始相对于掩蔽声有延迟，那么在信号频率处有频谱间隙的宽带掩蔽声中，音调信号的检测得到改善。这种听觉增强可能基于有效信号电平的增加，而不是有效掩蔽声电平的下降。为了评估这种信号增强在听力阈值处是否也存在，我们测量了有和没有前置带阻噪声时不同频率纯音脉冲的绝对阈值。这种噪声还会引起齐克威克音的感觉——一种在噪声呈现后立即持续几秒钟的微弱纯音。这种感觉的音高是噪声参数的复杂函数，但总是位于被抑制频段内的一个频率上。在齐克威克音感觉期间，与齐克威克音相邻频率的音调脉冲的听觉敏感性提高了多达13分贝，而不是像由于同时可听到的齐克威克音的存在而可能预期的那样降低。低频音未能影响这种阈值变化以及对耳朵声学响应的测量表明，这种阈值改善可能是通过神经元去抑制而不是通过耳蜗中机械抑制的解除产生的。
