Lack of effect of dorsomedial thalamic lesions on automated tests of spatial memory in the rat.

The effects of cytotoxic lesions of nucleus medialis dorsalis on tests of spatial memory were examined in the rat. Extensive lesions of the nucleus did not impair either the acquisition or the subsequent performance of an automated test of working memory, delayed nonmatching-to-position. Detailed analysis of the animals' performance over varying retention delays failed to reveal any evidence of a deficit. The same animals performed normally in a spatial discrimination task and its subsequent reversals. The present results can be contrasted with those from animals with hippocampal system damage.