Polich J
Department of Neuropharmacology, Research Institute of Scripps Clinic La Jolla, CA 92037.
Int J Psychophysiol. 1990 Dec;10(2):163-70. doi: 10.1016/0167-8760(90)90030-h.
The relationship between target stimulus probability and inter-stimulus interval (ISI) on the P300 (P3) component of the event-related potential was assessed in two experiments. An auditory discrimination paradigm was employed wherein subjects indicated with a finger tap response the occurrence of a randomly presented 2000 Hz target tone embedded in a series of 1000 Hz tones. Experiment 1 presented stimuli with target probabilities of 0.10, 0.30, and 0.50 at ISIs of 1.5 or 3.0 s and produced P3 amplitudes which decreased with increases in target probability and were smaller at the shorter compared to the longer ISI. Experiment 2 presented stimuli with target probabilities of either 0.20, 0.50, or 0.80 at ISIs of 4.0 and 10.0 s and produced P3 amplitudes which were unaffected by either variable. P3 latency demonstrated relatively few changes in either experiment. When taken together with previous findings, the results suggest that inter-stimulus interval affects P3 amplitude by determining the amount of processing resources available during ERP generation.
在两项实验中评估了事件相关电位的P300（P3）成分上目标刺激概率与刺激间隔（ISI）之间的关系。采用了一种听觉辨别范式，其中受试者通过轻敲手指来对嵌入在一系列1000赫兹音调中的随机呈现的2000赫兹目标音调的出现做出反应。实验1在1.5秒或3.0秒的刺激间隔下呈现目标概率为0.10、0.30和0.50的刺激，并产生P3波幅，其随目标概率增加而降低，且与较长刺激间隔相比，在较短刺激间隔时更小。实验2在4.0秒和10.0秒的刺激间隔下呈现目标概率为0.20、0.50或0.80的刺激，并产生不受任何一个变量影响的P3波幅。在两项实验中，P3潜伏期显示出相对较少的变化。与先前的研究结果结合起来看，这些结果表明刺激间隔通过确定事件相关电位产生期间可用的处理资源量来影响P3波幅。
