Folland Nicole A, Butler Blake E, Payne Jennifer E, Trainor Laurel J
McMaster University, Hamilton, Ontario, Canada.
J Cogn Neurosci. 2015 May;27(5):1060-7. doi: 10.1162/jocn_a_00764. Epub 2014 Dec 1.
Sound waves emitted by two or more simultaneous sources reach the ear as one complex waveform. Auditory scene analysis involves parsing a complex waveform into separate perceptual representations of the sound sources [Bregman, A. S. Auditory scene analysis: The perceptual organization of sounds. London: MIT Press, 1990]. Harmonicity provides an important cue for auditory scene analysis. Normally, harmonics at integer multiples of a fundamental frequency are perceived as one sound with a pitch corresponding to the fundamental frequency. However, when one harmonic in such a complex, pitch-evoking sound is sufficiently mistuned, that harmonic emerges from the complex tone and is perceived as a separate auditory object. Previous work has shown that the percept of two objects is indexed in both children and adults by the object-related negativity component of the ERP derived from EEG recordings [Alain, C., Arnott, S. T., & Picton, T. W. Bottom-up and top-down influences on auditory scene analysis: Evidence from event-related brain potentials. Journal of Experimental Psychology: Human Perception and Performance, 27, 1072-1089, 2001]. Here we examine the emergence of object-related responses to an 8% harmonic mistuning in infants between 2 and 12 months of age. Two-month-old infants showed no significant object-related response. However, in 4- to 12-month-old infants, a significant frontally positive component was present, and by 8-12 months, a significant frontocentral object-related negativity was present, similar to that seen in older children and adults. This is in accordance with previous research demonstrating that infants younger than 4 months of age do not integrate harmonic information to perceive pitch when the fundamental is missing [He, C., Hotson, L., & Trainor, L. J. Maturation of cortical mismatch mismatch responses to occasional pitch change in early infancy: Effects of presentation rate and magnitude of change. Neuropsychologia, 47, 218-229, 2009]. The results indicate that the ability to use harmonic information to segregate simultaneous sounds emerges at the cortical level between 2 and 4 months of age.
由两个或多个同时发声的声源发出的声波,以一种复杂的波形传入耳朵。听觉场景分析涉及将复杂波形解析为声源的独立感知表征[布雷格曼,A. S.《听觉场景分析:声音的感知组织》。伦敦:麻省理工学院出版社,1990年]。谐波性为听觉场景分析提供了一个重要线索。通常,基频整数倍的谐波被感知为一个音高与基频相对应的声音。然而,当这样一个引发音高的复杂声音中的一个谐波严重失谐时,该谐波会从复合音中凸显出来,并被感知为一个独立的听觉对象。先前的研究表明,通过脑电图记录得出的事件相关电位(ERP)中与对象相关的负性成分,在儿童和成人中都能为两个对象的感知提供指标[阿兰,C.,阿诺特,S. T.,&皮克顿,T. W.自下而上和自上而下对听觉场景分析的影响:来自事件相关脑电位的证据。《实验心理学杂志:人类感知与表现》,27,1072 - 1089,2001年]。在此,我们研究2至12个月大婴儿对8%谐波失谐的与对象相关反应的出现情况。两个月大的婴儿未表现出显著的与对象相关反应。然而,在4至12个月大的婴儿中,出现了一个显著的额部正性成分,到8至12个月时,出现了一个显著的额中央与对象相关的负性成分,这与年龄较大的儿童和成人中所见的情况类似。这与先前的研究一致,该研究表明,4个月以下的婴儿在基频缺失时不会整合谐波信息来感知音高[何,C.,霍特森,L.,&特雷纳,L. J.婴儿早期对偶尔音高变化的皮质失配反应的成熟:呈现速率和变化幅度的影响。《神经心理学》,47,218 - 229,2009年]。结果表明,利用谐波信息分离同时发声的声音的能力在2至4个月大时在皮质水平出现。