Analyses of factors that determine the context dependency of conditioned aversion

本研究旨在探讨大鼠条件性厌恶的语境依赖中语境获得的性质。条件性厌恶的情境依赖性是在情境辨别过程中建立的，在该过程中，大鼠在一个情境中被给予一些流体的配对呈现，而在另一个情境中被单独给予相同的流体。结果，大鼠只在前一种情况下避免摄入液体。关于语境在语境依赖形成中的作用，提出了两种可能的解释。一个假设，条件的上下文直接与恶心，而另一种认为，上下文获得的场合设置器，这决定了流体的有效性，恶心association.To评估这两种解释的有效性，因素，确定是否获得的上下文依赖性的流体转移到第二流体中的几个实验进行了检查。他们发现，大鼠将获得的背景依赖性转移到第二种液体中，而不管这种液体是新的还是熟悉的。相反，在两种情境和被试的笼子里呈现相同的液体，导致了厌恶的情境依赖性。而且，这种特定于液体的情境依赖性一旦建立，当被试接受一些扩展的辨别训练时就消失了。这些发现可以通过一个假设来解释，即情境和液体都直接与恶心相关，厌恶的明显语境依赖性是这两种关联的总和效应的结果。

This study aimed to investigate the property of the context acquired in the context dependency of conditioned aversion in the rats. Context dependency of conditioned aversion is established during the context discrimination procedure, in which rats are given paired presentation of some fluid in one context while given the same fluid alone in another context. As a result, rats come to avoid consuming the fluid only in the former.Two possible explanations on the role of the context in the formation of the context dependency have been proposed. One assumes that the conditioned context directly associates with nausea, while the other argues that the context acquires the property of occasion setter, which determines the effectiveness of the fluid-nausea association.In order to evaluate the validity of these two explanations, factors that determine whether the context dependency acquired to a fluid transferred to a second fluid was examined in the several experiments. They showed that rats transferred the acquired context dependency to the second fluid irrespective of whether the fluid was novel or familiar. Rather, presentation of the same fluid both in the two contexts and the home cages of the subjects resulted in the context dependency of aversion which was specific to it. Furthermore, such a fluid-specific context dependency once established disappeared when the subjects were given some extended discrimination trainings.These findings can be explained by an assumption that both the context and the fluid directly associate with nausea, and that the apparent context dependency of aversion is a consequence of the summation effect of these two associations.