Defective Processing of Contextual Information May Be Involved in the Poor Performance of DBA/2 Mice in Spatial Tasks

These experiments examine the influence of context manipulations on radial maze performance in C57BL/6 (C57) and DBA/2 (DBA) mice. Animals from each strain were trained in two distinct contexts--poor cuing vs rich cuing--that were sucessively switched. The results first show that C57 performed better when trained under rich cuing conditions than under poor ones, whereas DBA performed poorly under both conditions. In addition, contextual manipulations were found to produce more drastic effects in C57 than in DBA mice. That is, C57 showed a strong performance decrement following each context shift, whereas DBA mice did not. In particular, the fact that DBA mice performed similarly under rich and poor cuing conditions and also reacted mildly--or did not react--to context shifts suggests a deficit in processing contextual information, which places important constraints on their capability to form spatial representations.