Department of Experimental Psychology, University of Cambridge, Downing Street, Cambridge CB2 3EB, England.
J Acoust Soc Am. 2011 May;129(5):3181-93. doi: 10.1121/1.3560122.
Comodulation masking release (CMR), assessed using a flanking-band (FB) paradigm, may reflect the contribution of both across- and within-channel cues when FBs are proximal to the signal frequency. This study examined the effect of disrupting within-channel cues based upon envelope beats at the output of an auditory filter centered at the signal frequency, using a method described by Richards [(1988) Hear. Res. 35, 47-58], here called "on-frequency band (OFB) reversal." This removed regular beats for a pair of proximal FBs centered symmetrically about the OFB on a linear frequency scale (but not for a single FB that had the same center frequency as either of the constituent FBs in a pair) while maintaining the comodulation of individual noise bands that provides the basis for across-channel processes. OFB reversal consistently reduced CMR for proximal FB pairs--but not for a single FB or distal FB pair or when the FBs were presented in the opposite ear to the signal plus OFB--across a range of signal frequencies and for continuous and gated noise presentation. Simulations indicated that OFB reversal reduces the availability of within-channel cues based upon temporal fine structure and changes in envelope statistics.
调制掩蔽释放（CMR），使用侧翼带（FB）范式进行评估，当 FB 接近信号频率时，可能反映了跨通道和通道内线索的贡献。本研究使用 Richards（1988 年）提出的一种方法（Hear. Res. 35, 47-58），通过扰乱中心频率在信号频率处的听觉滤波器输出处的包络拍频（基于 envelope beats）产生的通道内线索，考察了基于频率包络反转（OFB）对通道内线索的破坏效果。这种方法在线性频率尺度上对中心频率对称的近端 FB 对（而不是单个 FB，该单个 FB 与一对 FB 中的任何一个具有相同的中心频率）进行了 OFB 反转，同时保持了提供跨通道过程基础的各个噪声带的调制。OFB 反转一致地降低了近端 FB 对的 CMR——但不影响单个 FB 或远端 FB 对，也不影响 FB 出现在信号和 OFB 的对侧耳朵时，跨越一系列信号频率，以及连续和门控噪声呈现时。模拟表明，OFB 反转降低了基于时间精细结构和包络统计变化的通道内线索的可用性。
