Suresh Chandan H, Krishnan Ananthanarayan, Gandour Jackson T
Purdue University, Department of Speech Language Hearing Sciences, Lyles-Porter Hall, 715 Clinic Drive, West Lafayette, IN, 47907-2122, USA.
Hear Res. 2017 Nov;355:42-53. doi: 10.1016/j.heares.2017.09.006. Epub 2017 Sep 14.
Long-term experience enhances neural representation of temporal attributes of pitch in the brainstem and auditory cortex in favorable listening conditions. Herein we examine whether cortical pitch mechanisms shaped by language experience are more resilient to degradation in background noise, and exhibit greater binaural release from masking (BRM). Cortical pitch responses (CPR) were recorded from Mandarin- and English-speaking natives using a Mandarin word exhibiting a high rising pitch (/yi/). Stimuli were presented diotically in Quiet, and in noise at +5, and 0 dB SNR. CPRs were also recorded in binaural conditions, SONO (where signal and noise were in phase at both ears); or S0Nπ (where signal was in phase and noise 180° out of phase at each ear), using 0 dB SNR. At Fz, both groups showed increase in CPR peak latency and decrease in amplitude with increasing noise level. A language-dependent enhancement of Na-Pb amplitude (Chinese > English) was restricted to Quiet and +5 dB SNR conditions. At T7/T8 electrode sites, Chinese natives exhibited a rightward asymmetry for both CPR components. A language-dependent effect (Chinese > English) was restricted to T8. Regarding BRM, both CPR components showed greater response amplitude for the S0Nπ condition compared to S0N0 across groups. Rightward asymmetry for BRM in the Chinese group indicates experience-dependent recruitment of right auditory cortex. Restriction of the advantage in pitch representation to the quiet and +5 SNR conditions, and the absence of group differences in the binaural release from masking, suggest that language experience affords limited advantage in the neural representation of pitch-relevant information in the auditory cortex under adverse listening conditions.
长期经验可增强脑干和听觉皮层在良好聆听条件下对音高时间属性的神经表征。在此，我们研究由语言经验塑造的皮层音高机制在背景噪声中是否更具抗降解能力，以及是否表现出更大的双耳掩蔽释放（BRM）。使用一个具有高音调上升的普通话单词（/yi/），记录了说普通话和英语的母语者的皮层音高反应（CPR）。刺激以双耳方式呈现于安静环境中，以及信噪比为+5和0 dB的噪声环境中。还在双耳条件下记录了CPR，即SONO（信号和噪声在双耳均同相）；或S0Nπ（信号同相，噪声在每只耳朵处相差180°），使用0 dB SNR。在Fz处，随着噪声水平增加，两组的CPR峰值潜伏期均增加，幅度均减小。Na-Pb幅度的语言依赖性增强（中文>英文）仅限于安静和+5 dB SNR条件。在T7/T8电极位点，中国母语者的CPR两个成分均表现出向右不对称。语言依赖性效应（中文>英文）仅限于T8。关于BRM，与S0N0相比，两组的CPR两个成分在S0Nπ条件下均表现出更大的反应幅度。中国组BRM的向右不对称表明右侧听觉皮层的经验依赖性募集。音高表征优势仅限于安静和+5 SNR条件，且在双耳掩蔽释放方面不存在组间差异，这表明在不利聆听条件下，语言经验在听觉皮层中与音高相关信息的神经表征方面提供的优势有限。
