Williams Douglas A, MacKenzie Heather K, Johns Kenneth W
Department of Psychology, University of Winnipeg, Winnipeg, Manitoba, Canada, R3B 2E9.
J Exp Psychol Anim Behav Process. 2010 Apr;36(2):232-42. doi: 10.1037/a0016922.
One way to minimize excitation acquired by the conditioned stimulus (CS) is to introduce intertrial presentations of the unconditioned stimulus (US). However, even in the presence of frequent intertrial USs, Experiments 1a and 1b found that rats anticipated the customary arrival time of a food pellet US when it occurred before (embedded)-versus coincident with (delay)-the termination of a white noise CS. Delay conditioning emerged in Experiment 2 in the absence of intertrial USs; hence, the detrimental effects of intertrial USs depended on the CS-US relationship, delay versus embedded, and not the duration of CS-US interval. Experiments 3a, 3b, and 4 found that random USs located in the early portion of the intertrial interval increased the control acquired by contextual stimuli at the expense of temporal stimuli occasioned near CS termination. Our results suggest that delay relationships leave the CS especially vulnerable to the deleterious effects of intertrial USs.
使条件刺激（CS）获得的兴奋最小化的一种方法是在试验间隙引入非条件刺激（US）。然而，即使在试验间隙频繁出现非条件刺激的情况下，实验1a和1b发现，当食物颗粒非条件刺激出现在白噪声条件刺激终止之前（嵌入）而非与之同时（延迟）时，大鼠会预期其惯常的到来时间。在没有试验间隙非条件刺激的情况下，实验2出现了延迟条件作用；因此，试验间隙非条件刺激的有害影响取决于条件刺激与非条件刺激的关系，即延迟与嵌入，而不是条件刺激 - 非条件刺激间隔的持续时间。实验3a、3b和4发现，位于试验间隙早期的随机非条件刺激增加了情境刺激获得的控制，代价是在条件刺激终止附近产生的时间刺激。我们的结果表明，延迟关系使条件刺激特别容易受到试验间隙非条件刺激的有害影响。
