Westenberg I S, Weinberger N M
Electroencephalogr Clin Neurophysiol. 1976 Apr;40(4):356-69. doi: 10.1016/0013-4694(76)90187-5.
The goal of the present experiment was to rule out the hypothesis that evoked potential (EP) decrements during repetitive stimulation are due to a change in the subject's state; i.e., that the decrements are part of general, nonselective, non-specific decrement in all EPs as a result of a change in state during the course of the experiment. To this end, we obtained average evoked potentials (AEPs) to tone pips of two different frequencies; pips of one frequency were the repetitive stimuli, one and pips of the other frequency served as "test" stimuli. Before and again after a 15 min series of repetitive pips, AEPs to the repetitive stimuli and to the test stimuli were obtained. We found that from the beginning to the end of the 15 min repetitive-pip series, certain components of the AEPs to the repetitive stimuli decreased significantly in amplitude. However, comparable components in the AEPs to the test stimuli did not demonstrate significant decrements. These results suggested that the decrements were not part of a non-selective, non-specific, state-related decrement in all AEPs. However, the selective decrements could have been attributable to either of two aspects of the repetitive tone pips; their repetitive aspect, or their frequency. Because there were two independent variables, a counterbalanced design was required. We found that regardless of which frequency was repetitive, there were significant decrements in the AEPs to the repetitive stimuli and smaller decrements (if any) in the AEPs to the test stimuli. This ruled out the frequencies of the tone pips as critical factors in the decrements; by the process of elimination the repetitive aspect of the stimuli remained as the critical variable. Only decrements that were specific to the repetitive stimulus were considered to be habituatory. All of the habituatory decrements were in components subsequent to the initial AEP components and had latencies in the range of 17--105 msec. In several cases, when subjects participated in a supplemental experiment, the same AEP components demonstrated habituatory decrements in both experiments.
本实验的目的是排除这样一种假设，即重复刺激期间诱发电位（EP）的衰减是由于受试者状态的改变；也就是说，这些衰减是实验过程中状态改变导致的所有EP普遍、非选择性、非特异性衰减的一部分。为此，我们获取了对两种不同频率短纯音的平均诱发电位（AEP）；一种频率的短纯音是重复刺激，另一种频率的短纯音作为“测试”刺激。在一系列15分钟的重复短纯音刺激之前和之后，分别获取了对重复刺激和测试刺激的AEP。我们发现，在15分钟的重复短纯音刺激系列开始到结束期间，对重复刺激的AEP的某些成分幅度显著下降。然而，对测试刺激的AEP中类似成分并未表现出显著衰减。这些结果表明，这些衰减并非所有AEP中与状态相关的非选择性、非特异性衰减的一部分。然而，选择性衰减可能归因于重复短纯音的两个方面；其重复特性，或其频率。由于存在两个独立变量，需要采用平衡设计。我们发现，无论哪种频率是重复频率，对重复刺激的AEP都会有显著衰减，而对测试刺激的AEP衰减较小（如有）。这排除了短纯音频率是衰减的关键因素；通过排除过程，刺激的重复特性仍然是关键变量。只有特定于重复刺激的衰减才被认为是习惯性的。所有习惯性衰减都出现在初始AEP成分之后的成分中，潜伏期在17 - 105毫秒范围内。在几个案例中，当受试者参与补充实验时，相同的AEP成分在两个实验中都表现出习惯性衰减。
