Xavier G F, Bueno O F
Braz J Med Biol Res. 1984;17(1):55-64.
Some procedures commonly employed in testing hypotheses of instrumental learning and classical conditioning as applied to the step-through passive avoidance task in rats are examined. In Experiment I, a 'delay-of-punishment gradient', i.e., decreased passive avoidance performance, was obtained by increasing response-shock time intervals (from 0 to 600 s) in training sessions. In Experiment II, decreased passive avoidance behavior was also obtained by submitting animals to nonreinforced preexposure (0 to 600 s) in the shock compartment prior to their receiving shock contingent on the response in training sessions. Experiment III repeated the 'delay-of-punishment gradient' and showed that adequate nonreinforced preexposure time before training decreases passive avoidance performance in animals trained through a noncontingent procedure. The results clearly show that environment training preexposure has a decreasing effect on passive avoidance performance. Increasing response-shock interval also has a decremental effect on this task. With large time intervals the latter effect can be explained as the result of preexposure to the training environment; the possibility of interaction between both processes was not discarded. For smaller time ranges (up to 30 s), the usual interpretation of 'delay-of-punishment gradient', namely decreased response-shock association, seems to be adequate to account for the results.
本文考察了一些常用于检验将工具性学习和经典条件作用的假设应用于大鼠穿梭箱被动回避任务的程序。在实验I中，通过在训练过程中增加反应-电击时间间隔（从0到600秒），获得了“惩罚延迟梯度”，即被动回避表现下降。在实验II中，在训练过程中，动物在电击隔室中接受无强化的预暴露（0到600秒），然后根据反应接受电击，也获得了被动回避行为下降的结果。实验III重复了“惩罚延迟梯度”，并表明在通过非偶然程序训练的动物中，训练前适当的无强化预暴露时间会降低被动回避表现。结果清楚地表明，环境训练预暴露对被动回避表现有降低作用。增加反应-电击间隔对该任务也有递减作用。对于较大的时间间隔，后一种效应可以解释为预暴露于训练环境的结果；并未排除这两个过程之间相互作用的可能性。对于较小的时间范围（最多30秒），“惩罚延迟梯度”的通常解释，即反应-电击关联减弱，似乎足以解释结果。
