Department of Experimental Audiology, Otto von Guericke University Magdeburg, Leipziger Str. 44, 39120 Magdeburg, Germany.
Hear Res. 2012 Mar;285(1-2):77-85. doi: 10.1016/j.heares.2012.01.006. Epub 2012 Feb 3.
The present study was aimed at investigating the relationship between the mismatch negativity (MMN) and psychoacoustical effects of sequential streaming on comodulation masking release (CMR). The influence of sequential streaming on CMR was investigated using a psychoacoustical alternative forced-choice procedure and electroencephalography (EEG) for the same group of subjects. The psychoacoustical data showed, that adding precursors comprising of only off-signal-frequency maskers abolished the CMR. Complementary EEG data showed an MMN irrespective of the masker envelope correlation across frequency when only the off-signal-frequency masker components were present. The addition of such precursors promotes a separation of the on- and off-frequency masker components into distinct auditory objects preventing the auditory system from using comodulation as an additional cue. A frequency-specific adaptation changing the representation of the flanking bands in the streaming conditions may also contribute to the reduction of CMR in the stream conditions, however, it is unlikely that adaptation is the primary reason for the streaming effect. A neurophysiological correlate of sequential streaming was found in EEG data using MMN, but the magnitude of the MMN was not correlated with the audibility of the signal in CMR experiments. Dipole source analysis indicated different cortical regions involved in processing auditory streaming and modulation detection. In particular, neural sources for processing auditory streaming include cortical regions involved in decision-making.
本研究旨在探讨失匹配负波（MMN）与序列流对共调掩蔽释放（CMR）的心理声学效应之间的关系。使用相同组的受试者的心理声学替代强迫选择程序和脑电图（EEG）研究了序列流对 CMR 的影响。心理声学数据表明，仅添加由仅失信号频率掩蔽器组成的前导序列会消除 CMR。补充的 EEG 数据显示，当仅存在失信号频率掩蔽器分量时，即使掩蔽器包络相关性跨频率，也会产生 MMN。添加这样的前导序列可以将同频和失频掩蔽器分量分离成不同的听觉对象，从而防止听觉系统将共调作为附加线索。在流条件下，改变侧翼带表示的频率特异性适应也可能导致 CMR 的减少，但是，适应不太可能是流条件影响的主要原因。在 EEG 数据中使用 MMN 找到了序列流的神经生理学相关性，但是 MMN 的幅度与 CMR 实验中信号的可听度无关。偶极子源分析表明，在处理听觉流和调制检测的过程中涉及不同的皮质区域。特别是，用于处理听觉流的神经源包括涉及决策的皮质区域。
