Delayed-alternation performance after kainic acid lesions of the thalamic mediodorsal nucleus and the ventral tegmental area in the rat.

The relative importance of two subcortical structures, projecting to the rat's prefrontal cortex, in mediation of delayed-alternation performance, was tested. These structures, the thalamic mediodorsal nucleus and the ventral tegmental area, were lesioned with kainic acid after the rats had learned a spatial delayed-alternation task. It was found that both structures are apparently involved to a similar degree in the performance of this task and that the behavior of both experimental groups differed from that of a sham-operated control group of rats.