Schröger E
Institut für Psychologie, Ludwig-Maximilians-Universität München, Germany. schrogergmip.pacd.uni-muenchen.de
Electroencephalogr Clin Neurophysiol. 1996 Nov;100(6):517-26.
This study illuminates processes underlying change detection for different features (detection of pitch versus loudness changes) and different amounts of attentional allocation (automatic versus attentive change detection). For this reason, the influence of important stimulus characteristics (intensity and inter-stimulus interval (ISI)) on these different types of change detection was determined. By varying intensity, it should be clarified whether these processes are mainly sensitive to the informational content of the change or to the total amount of stimulus energy. By varying ISI, it should be determined whether they are differentially sensitive to manipulations of encoding time and/or state of sensory refractoriness. Automatic change detection was indexed by the mismatch negativity (MMN), which is a component of the event-related brain potential (ERP). Attentive change detection was indexed by the N2b and P3 components of the ERP and by behavioral performance. Human subjects were presented with a high-probability standard tone and a low-probability deviant-tone, which differed from the standard tone in frequency (Experiment I) or intensity (Experiment II). In separate blocks, the intensities of the standard stimuli were of 55 and 70 dB SPL and ISIs were of 350 and 950 ms. During the first part of the experiments, subjects were engaged in silent reading, whereas they tried to discriminate deviants from standards in the second part. The MMN elicited by a frequency change was invariant to variations in intensity and ISI, whereas the MMN elicited by an intensity change was significantly modulated by both intensity and ISI. This implies functional differences between the neural traces underlying the frequency-MMN and the intensity-MMN. In addition, there were larger effects of the ISI on the N2b and P3 amplitudes as compared with the effects on the MMN amplitudes, suggesting stronger capacity limitations for attentive change detection than for automatic change detection.
本研究阐明了针对不同特征（音高变化与响度变化的检测）以及不同注意力分配量（自动与注意力集中的变化检测）的变化检测背后的过程。因此，确定了重要刺激特征（强度和刺激间隔（ISI））对这些不同类型变化检测的影响。通过改变强度，应阐明这些过程主要是对变化的信息内容敏感还是对刺激能量的总量敏感。通过改变ISI，应确定它们对编码时间和/或感觉不应期状态的操纵是否具有不同的敏感性。自动变化检测通过失配负波（MMN）来索引，MMN是事件相关脑电位（ERP）的一个成分。注意力集中的变化检测通过ERP的N2b和P3成分以及行为表现来索引。向人类受试者呈现高概率的标准音和低概率的偏差音，偏差音在频率（实验I）或强度（实验II）上与标准音不同。在不同的组块中，标准刺激的强度为55和70 dB SPL，ISI为350和950 ms。在实验的第一部分，受试者进行默读，而在第二部分他们试图区分偏差音和标准音。由频率变化引发的MMN对强度和ISI的变化不敏感，而由强度变化引发的MMN则受到强度和ISI两者的显著调制。这意味着频率-MMN和强度-MMN背后的神经痕迹存在功能差异。此外，与对MMN波幅的影响相比，ISI对N2b和P3波幅的影响更大，这表明注意力集中的变化检测比自动变化检测具有更强的容量限制。
