本文旨在研究音乐训练是否能增强基于音高和空间位置的听觉选择性注意力,以及音乐训练对听觉可塑性的神经机制.听觉感知实验中,受试者根据音高差异或空间位置差异,选择两个同时播放的数字之一.听觉认知实验在安静和噪声环境中播放频率分辨率不同的复合音,记录受试者听觉脑干频率跟随响应(frequency-following responses,FFRs).本文提出分析FFR的四种方法,即包络相关频率跟随响应(envelope-related frequency-following response,FFRENV)的短时锁相值、瞬时相位差极性图、相位差均值矢量以及时间细节结构相关频率跟随响应(temporal-fine-structure-related frequency-following response,FFRTFS)的幅度谱信噪比.实验结果表明,在完成基于音高的任务时,受过音乐训练的受试者准确率更高、反应时间更短.外界噪声不影响两组人群在基频(fundamental frequency,F0)的神经元锁相能力,但是显著降低了谐波处的神经元锁相能力.受过音乐训练的受试者的神经元在基频处的锁相能力和谐波处抗噪能力均增强,且其FFRTFS幅度谱信噪比与基于音高的行为学准确率呈正相关.因此,受过音乐训练的受试者其音高选择性注意感知能力的提高取决于认知神经能力的增强,经过音乐训练后,F0处FFRENV的锁相能力、谐波处FFRTFS的抗噪和持续锁相能力以及谐波处FFRTFS幅度谱信噪比均明显增强.音乐训练对听觉选择性注意具有显著的可塑性.
This study explores whether musical training is able to enhance the perception of pitch-and locationbased selective auditory attention,then analyzes the corresponding neural mechanism of the auditory plasticity through musical training.In the auditory perception experiment,listeners were instructed to select one of two simultaneous digits based on either the target digit's pitch or location.In the auditory cognitive experiment,the listeners' brainstem frequency-following responses(FFRs)were recorded in response to the complex tones with various frequency resolutions in both quiet and in noisy acoustic environments.Further,four approaches of FFR analysis were proposed,including short-term phasing locking value of envelope-related frequency-following response(FFRENV),polar of FFR's instantaneous phase difference,vector of FFR's grand averaged phase difference,and spectrum signal-to-noise ratio of temporal-fine-structure-related frequency-following response(FFRTFS).Results show that compared to non-musicians,listeners with musical training were both more accurate at reporting the target digit and had a shorter reaction time,especially for attend-pitch trials.For both groups,noise had little effect on the neural encoding of the fundamental frequency(F0) but significantly degraded the neural encoding of harmonics.Compared to non-musicians,musicians showed enhanced phase locking of F0 as well as more robust phase locking to stimulus harmonics in the noise condition.Neural spectrum SNRs of FFRTFSto harmonics were correlated with listeners' behavioral correction rate on the pitch-based auditory attention,for which robustness of musicians' FFR out performed the non-musicians'.These findings suggest musician's better pitch perception in auditory selective attention is relevant to their enhanced neural cognition.Musical training is assumed to be able to enhance the FFRENVphase locking to the F0,the robustness and continuous phase locking of FFRTFSto the harmonics,and spectrum SNR FFRTFSto the