似昼夜节律与学习效应对脑事件相关电位P300的影响

目的 探讨昼夜节律和学习效应对脑事件相关电位P300成分的影响。方法 8名被试者在非连续的5d的实验中每天在5个时间点（7：00，12：00，16：00，20：00和0：00）重复相同的听觉Oddball模式测试以诱发脑事件相关电位（ERP）。然后测量各次的ERPP300成分，得到其潜伏期及波幅。结果 P300波幅明显高于下午的波辐。重复测量也使P300波幅从第1个实验日的平均13.0uV降至第5个实验日的9.2uV。P300潜伏期随着重复测试的增加出现了习服，它从第2个实验日的平均350.6ms缩短为第5个实验日的平均343.5ms.结论 似昼夜节律和学习效应对脑事件相关电位P300成分的波幅和潜伏期均有影响。

Both circadian rhythm and repeated-testing act on event rela ted potential P300

AIM　To investigate the effects of circadian rhythm an d repeated testi ng on event related potential (ERP) P300 component. METHODS　Every subject (n=8) was tes-ted with a standard aural oddball paradigm to obtain ERP P300 . They w ere tested at 5 timepoints (7:00, 12:00, 16:00, 20:00, 0:00) per day in 5 days w ith an interval of at least 1 wk between 2 test days. In each test ERP was recorded. RESULTS　Amplitude and latency of P300 changed with the time of the day. Th e amplitude of P300 was significantly higher in the morning than in the af ternoo n. It also habituated across test days from a mean of 13.0 μV on the 1st day t o a mean of 9.2 μV on the 5th day. Latency of P300 also habituated across test da ys; it decreased from a mean of 350.6 ms on the 2nd day to a mean of 343.5 ms on the 5th day. CONCLUSION　Both circadian rhythm and repeated testing can influence amplitude and latency of ERP P300.