Marklund Ellen, Gustavsson Lisa, Kallioinen Petter, Schwarz Iris-Corinna
Phonetics Laboratory, Department of Linguistics, Stockholm University, Stockholm, Sweden.
Front Hum Neurosci. 2020 Oct 29;14:534804. doi: 10.3389/fnhum.2020.534804. eCollection 2020.
The amplitude of the event-related N1 wave decreases with repeated stimulation. This repetition-attenuation has not previously been investigated in response to variable auditory stimuli, nor has the relative impact of acoustic vs. perceptual category repetition been studied. In the present study, N1 repetition-attenuation was investigated for speech and spectrally rotated speech with varying degrees of acoustic and perceptual category variation. In the speech condition, participants ( = 19) listened to stimulus trains consisting of either the same vowel exemplar (no variability condition), different exemplars of the same vowel (low variability condition), or different exemplars of two different vowels (high variability condition). In the rotated speech condition, the spectrally rotated counterparts of the vowels were presented. Findings show N1 repetition-attenuation in the face of acoustic and perceptual category variability, but no impact of the degree of variability on the degree of N1 attenuation. Speech stimuli resulted in less attenuation than the acoustically matched non-speech stimuli, which is in line with previous findings. It remains unclear if the attenuation of the N1 wave is reduced as a result of stimuli being perceived as belonging to perceptual categories or as a result of some other characteristic of speech.
事件相关N1波的波幅会随着重复刺激而降低。此前尚未针对可变听觉刺激研究这种重复衰减，也未研究声学类别重复与感知类别重复的相对影响。在本研究中，针对具有不同程度声学和感知类别变化的语音以及频谱旋转语音，研究了N1重复衰减。在语音条件下，参与者（n = 19）聆听由相同元音示例（无变异性条件）、同一元音的不同示例（低变异性条件）或两个不同元音的不同示例（高变异性条件）组成的刺激序列。在频谱旋转语音条件下，呈现元音的频谱旋转对应物。研究结果表明，面对声学和感知类别变异性时存在N1重复衰减，但变异性程度对N1衰减程度没有影响。语音刺激导致的衰减比声学匹配的非语音刺激少，这与先前的研究结果一致。目前尚不清楚N1波的衰减是由于刺激被视为属于感知类别，还是由于语音的其他某些特征而降低。
