上期中会介绍了非条件反射与条件反射的基本概念,阐明了条件反射形成的机制,并且也指出了所谓条件反射乃是大脑皮层的「信号化」活动。这样,通过动物实验所获得的结论就不难理解过去曾经谈过的致病因子之一——中性刺激物的作用了。回想在第一期所举过的例子,就可以显然地判明。阿朴吗啡(催吐剂)是非条件的刺激物,而音叉则是中性刺激物。注射阿朴啡与敲打昔叉相结合多次后,仅仅音叉的响声就能引起与注射阿朴吗啡同样的作用;换句话说,音叉己经变成条件刺激物了。 In the last issue, we introduced the basic concepts of unconditional reflections and conditioned reflections, clarified the mechanism of conditioned reflexes, and also pointed out that so-called conditioned reflexes are “signaling” activities of the cerebral cortex. In this way, the conclusion obtained through animal experiments is not difficult to understand the effect of neutral stimuli, one of the pathogenic factors that have been talked about in the past. Recall the examples cited in the first issue, you can clearly determine. Apomorphine (emetic) is a nonconditional stimulus, while the tuning fork is a neutral stimulus. After the injection of aporphine and beating hook forks many times, just the sound of the tuning fork can cause the same effect as the injection of apomorphine; in other words, the tuning fork has become a conditioning stimulus.