音乐速度变化感知的失匹配负波

Mismatch Negativity in Perception of Temporal Disturbances in Music

感知速度变化对音乐认知具有重要意义。本研究采用5个鼓点音构成标准等间距序列,再通过调整序列第3个刺激间隔(IOI)的长度引入局部速度扰动(IOI缩短:加速;IOI延长:减速)。从行为实验及被动听觉脑电实验入手,记录被试主动检测三种典型序列速度(快速:IOI=300 ms;中速:IOI=600 ms;慢速:IOI=900 ms)下的局部IOI扰动的行为响应,及自动感知中速序列(IOI=600 ms)局部IOI扰动的脑电响应。行为数据显示:中速的响应精度显著大于快速和慢速;加速与减速的辨别力指数在快速和慢速下均有显著差异,而在中速下无显著差异。脑电数据显示:在额中区电极Fz处,加速的失匹配负波(MMN)比减速的幅度更大、潜伏期更早。实验结果表明,中速序列的局部速度扰动对MMN的影响显著不同;即使在行为无偏差的中等序列速度下,大脑对局部速度扰动的感知加工还是有差异的。

The perception of tempo variation is crucial for music cognition.In this paper,behavior and passive event-related potential（ERP） experiments were combined to investigate the pre-attentive perception of tempo disturbances within the behavioral unbiased time.A 5-beat isochronous sequence was adopted as a standard stimulus.The length of the 3rd inter onset interval（IOI） in the sequence was modulated（shortening or lengthening the standard IOI by 10%） to introduce two temporal disturbances（shortened IOI： acceleration;lengthened IOI： deceleration） as deviant stimuli.In behavior experiment,subjects were required to focus on each sequence,with three basic tempos（fast： IOI = 300 ms;modest： IOI = 600 ms;slow：IOI = 900 ms）,respectively,and discriminate the length variation of the third IOI.In the EEG experiment,only sequences with a modest basic tempo（IOI = 600 ms） were presented.The behavior data showed that the difference of discrimin nation index d’value between acceleration and deceleration was significant for fast or slow tempo,but not for modest tempo,indicating that no behaviorally perceptual bias was caused by the modest tempo.The ERP analysis showed that both the two temoporal disturbances elicited a frontally mismatch negativity（MMN）,with relatively earlier latency and greater magnitude for acceleration than that for deceleration.This work revealed that the temporal disturbances within modest tempo had a significantly different effect on the MMNs,suggesting that even at the behavioral unbiased tempo,the perception of acceleration and deceleration might still rely on different aspects of information processing.