Paavilainen P, Karlsson M L, Reinikainen K, Näätänen R
Department of Psychology, University of Helsinki, Finland.
Electroencephalogr Clin Neurophysiol. 1989 Aug;73(2):129-41. doi: 10.1016/0013-4694(89)90192-2.
Auditory stimulus blocks were presented to 12 reading subjects. Each block consisted of 2 types, standard (P = 90%) and deviant stimuli (P = 10%), delivered in a random order. The only difference between these stimuli was their spatial location of origin. The subject always heard the standards as coming straight in front and the deviants from an angle of either 10, 45, or 90 degrees to the right of the standards. The spatial locations were produced via earphones by introducing for low-frequency (600 Hz) tones an interaural phase difference and for high-frequency (3000 Hz) tones an interaural intensity difference. Standard and deviant stimuli were also delivered in more natural, free-field, conditions via differently positioned loudspeakers. The deviant tones elicited an event-related brain potential component called the mismatch negativity (MMN), followed by a P3a component. Thus changes in spatial location of an auditory stimulus produced by following either one of the two main principles of human sound localization elicited the MMN. Consequently, it was concluded that the spatial location of a sound source is coded in the hypothesized neuronal stimulus traces reflected by the MMN and, further, that a change in this location is automatically detected by the brain by means of the MMN generator process.
对12名阅读受试者呈现听觉刺激组块。每个组块由两种类型组成，标准刺激（概率为90%）和偏差刺激（概率为10%），以随机顺序呈现。这些刺激之间的唯一区别在于其起源的空间位置。受试者总是听到标准刺激直接来自正前方，而偏差刺激则来自标准刺激右侧10度、45度或90度的角度。通过耳机，对低频（600赫兹）音调引入耳间相位差，对高频（3000赫兹）音调引入耳间强度差，从而产生空间位置。标准刺激和偏差刺激也通过不同位置的扬声器在更自然的自由场条件下呈现。偏差音调引发了一种称为失配负波（MMN）的事件相关脑电位成分，随后是P3a成分。因此，遵循人类声音定位的两个主要原则之一所产生的听觉刺激空间位置变化引发了MMN。因此，得出的结论是，声源的空间位置在由MMN反映的假设神经元刺激痕迹中进行编码，而且，大脑通过MMN生成过程自动检测到该位置的变化。
