Avoidance and brightness discrimination conditioning in genetically different lines of rats.

Rats from an albino stock were selected for high (HAS) and low (LAS) avoidance scores measured in a shuttle-box. Learning performance of male rats was compared in three different tests: the shuttle-box, the pole jumping-box, and the Y-chamber. It was shown that rats of the HAS line more rapidly acquired conditioned avoidance in the shuttle-box experiment and the pole-jumping experiment than LAS, whereas we could not detect any significant differences in brightness discrimination. In the open field test rats of the HAS line were more active in comparison to LAS's, measured in terms of higher ambulation scores. In conclusion, it is verified that the shuttle-box performance as well as pole-jumping performance is highly determined by the emotional status of the animals and, moreover, that avoidance learning is based on mechanisms other than brightness discrimination learning.