Zieliński K, Werka T, Nikolaev E
Department of Neurophysiology, Nencki Institute of Experimental Biology, Warsaw, Poland.
Acta Neurobiol Exp (Wars). 1991;51(3-4):71-88.
Learning and performance of two-way avoidance were investigated in a total of 68 rats trained with either a visual (change in illumination to darkness or to light) or an auditory (white noise of 70 or 60 dB intensity) conditioned stimulus (CS). Experiment I showed that the darkness CS produce lower avoidance performance and a much higher rate of intertrial responses than either a auditory or a compound (visual plus auditory) CS. A monotonic within-session increase of avoidance performance and a similar, but less regular increase of intertrial responses were found at the beginning of training in each group. In later sessions such trends were observed only in rats trained with a visual CS. Experiments II and III showed also rapid transfer of avoidance response and a corresponding change of intertrial response rate with the change of CS modality. When the compound CS was used, the effects of the visual element were completely overcome by the auditory one. Rats trained with a visual CS in Experiment IV showed a positive correlation between avoidance performance and the number of intertrial responses, which was more pronounced in earlier than in later training sessions. We consider the rise of intertrial behaviour as an adaptive response to the increase of task difficulty. CSi of different modalities differ not only in relative saliency, but also in the discriminability between their onset and offset. The modality of the CS influences not only avoidance performance but also the course of learning.
我们对总共68只大鼠进行了双向回避学习与表现的研究，这些大鼠接受了视觉（光照变为黑暗或变为明亮）或听觉（强度为70或60分贝的白噪声）条件刺激（CS）的训练。实验一表明，与听觉或复合（视觉加听觉）CS相比，黑暗CS产生的回避表现更低，且试间反应率更高。在每组训练开始时，发现回避表现在训练过程中单调增加，试间反应也有类似但不太规律的增加。在随后的训练阶段，这种趋势仅在接受视觉CS训练的大鼠中观察到。实验二和实验三还表明，随着CS模式的改变，回避反应会迅速转移，试间反应率也会相应变化。当使用复合CS时，视觉元素的效果被听觉元素完全克服。在实验四中，接受视觉CS训练的大鼠在回避表现和试间反应次数之间呈现正相关，这种相关性在早期训练阶段比后期训练阶段更为明显。我们认为试间行为的增加是对任务难度增加的一种适应性反应。不同模式的CS不仅在相对显著性上存在差异，而且在其起始和终止的可辨别性上也有所不同。CS的模式不仅影响回避表现，还影响学习过程。
