Johnson B W, Muthukumaraswamy S D, Hautus M J, Gaetz W C, Cheyne D O
Department of Psychology, University of Auckland, New Zealand.
Neurol Clin Neurophysiol. 2004 Nov 30;2004:33.
In recent EEG investigations [Johnson, 2003] [Hautus, 2005], we described a novel late negative ERP component associated with binaural processing of auditory pitch based solely on interaural timing differences ("dichotic pitch"), an acoustic phenomenon that is closely analogous to visual perception of stereoscopic depth based on retinal disparities. The present study extends this research with neuromagnetic recordings of auditory evoked fields (AEFs) elicited by dichotically-embedded pitches. Eight healthy adult subjects listened to control stimuli consisting of 500 ms segments of broadband acoustic noise presented identically to both ears via earphones, and dichotic pitch stimuli created by introducing a dichotic delay to a narrow frequency region of the same noise segments and resulting in a perception of a pitch lateralized to the left or right of auditory space. Auditory-evoked fields (AEFs) were recorded using a 151 channel whole-head MEG system. Comparison of control and dichotic-pitch AEFs showed reliable amplitude differences during a time window of 150-350 ms. AEFs over the left hemisphere showed larger effects for contralateral than ipsilateral pitches, while the right hemisphere showed no differences for differently lateralized sources. The results indicate a relatively late stage of neural processing of binaurally-derived cues for the perceptual segregation of concurrent sound sources and support a right-hemisphere dominance for the processing of sound-source localization.
在最近的脑电图研究中[约翰逊,2003年][豪图斯,2005年],我们描述了一种新的晚期负性事件相关电位成分,它与仅基于双耳时间差异的听觉音高双耳处理(“双耳分听音高”)有关,这是一种声学现象,与基于视网膜视差的立体深度视觉感知密切类似。本研究通过对双耳嵌入音高诱发的听觉诱发电场(AEF)进行神经磁记录,扩展了这项研究。八名健康成年受试者聆听了对照刺激,即通过耳机向双耳同等呈现的500毫秒宽带噪声片段,以及通过对相同噪声片段的窄频率区域引入双耳延迟而产生的双耳分听音高刺激,从而产生一种在听觉空间左侧或右侧侧化的音高感知。使用151通道全头脑磁图系统记录听觉诱发电场(AEF)。对照和双耳分听音高AEF的比较显示,在150 - 350毫秒的时间窗口内存在可靠的幅度差异。左半球上的AEF对同侧音高的影响比对侧音高的影响更大,而右半球对不同侧化声源没有差异。结果表明,在神经处理双耳衍生线索以进行并发声源的感知分离方面,存在一个相对较晚的阶段,并支持右半球在声源定位处理方面的优势地位。