Lipp O V, Arnold S L, Siddle D A, Dawson M E
Department of Psychology, University of Queensland, Australia.
Biol Psychol. 1994 Sep;38(1):19-36. doi: 10.1016/0301-0511(94)90047-7.
The amplitude of a blink reflex is inhibited if the reflex eliciting stimulus is preceded by a short prestimulus (e.g. < 250 ms). If the prestimulus duration is longer than 1 s, blink reflex amplitude is facilitated. The present study investigated the effect of repeated presentations of prestimulus-blink eliciting stimulus pairings on blink reflex modulation. Subjects in Experiment 1 (N = 59) were presented with a sequence of 12 blocks of 7 trials. Within each block, one trial was a blink stimulus alone, whereas the blink stimulus was preceded by a prestimulus on the other trials. Prestimulus intervals were 30, 60, 120, 240, 500 and 2000 ms. Prestimuli were presented continuously throughout the prepulse interval. The amount of reflex magnitude inhibition at the 60, 120, 240 and 500 ms lead intervals and reflex latency shortening at 30 and 60 ms decreased over blocks. The amount of reflex facilitation at a lead interval of 2000 ms was not reduced. In Experiment 2 (N = 22), two groups of subjects were presented with a sequence of blink stimulus alone presentations and prestimulus-blink stimulus pairings. The prestimulus lasted for 120 ms in one group and for 200 ms in the second. Blink reflex magnitude inhibition declined in both groups over blocks of trials. However, the groups also differed in responding on the blink stimulus alone control trials. Experiment 3 (N = 24) employed the same design as did Experiment 2. No difference in control responding was found. Similar to Experiment 2, blink inhibition decreased over repeated trials in both groups. The present results indicate that prepulse inhibition reflects a process which is affected by repeated presentation of prestimulus-reflex stimulus pairings. However, the conclusion that the reduction of prestimulus effects reflects habituation seems to be premature.
如果在引发眨眼反射的刺激之前有一个短暂的预刺激（例如<250毫秒），眨眼反射的幅度会受到抑制。如果预刺激持续时间超过1秒，眨眼反射幅度会增强。本研究调查了重复呈现预刺激-眨眼引发刺激配对对眨眼反射调制的影响。实验1中的受试者（N = 59）接受了一系列12个块，每个块包含7次试验。在每个块中，一次试验仅为眨眼刺激，而在其他试验中，眨眼刺激之前有一个预刺激。预刺激间隔为30、60、120、240、500和2000毫秒。在整个预脉冲间隔期间持续呈现预刺激。在60、120、240和500毫秒的超前间隔下，反射幅度抑制量以及在30和60毫秒时反射潜伏期缩短量在各块试验中均有所下降。在2000毫秒超前间隔下的反射增强量没有减少。在实验2（N = 22）中，两组受试者分别接受了一系列仅为眨眼刺激的呈现以及预刺激-眨眼刺激配对。一组中预刺激持续120毫秒，另一组中持续200毫秒。在各试验块中，两组的眨眼反射幅度抑制均有所下降。然而，两组在仅为眨眼刺激的对照试验中的反应也存在差异。实验3（N = 24）采用了与实验2相同的设计。未发现对照反应有差异。与实验2类似，两组在重复试验中眨眼抑制均下降。目前的结果表明，预脉冲抑制反映了一个受预刺激-反射刺激配对重复呈现影响的过程。然而，关于预刺激效应的降低反映习惯化这一结论似乎还为时过早。
