Expression of the transcription factor Zif268 in the temporal cortex of monkeys during visual paired associate learning.

In humans and monkeys, memory consists of various components which were initially revealed through neuropsychological studies of amnesic patients. One memory component, the long-term memory about facts and events (declarative memory), has been shown to require the integrity of the medial temporal lobe and the neocortex. To investigate a map of gene expression during declarative memory formation in the primate, we monitored expression of immediate early genes in the temporal lobe of macaque monkeys. We trained the monkeys to learn visual associative memory tasks, and immunohistochemically analysed the expression of protein products of immediate early genes. We found that Zif268, a transcription factor regulated by neuronal activity, accumulated in patches in the anterior temporal lobe during visual stimulus-stimulus association learning, whereas other transcription factors, c-Fos and JunD, were not. By contrast, the patchy expression of Zif268 was not observed during another type of learning, visual discrimination learning. These results suggest that Zif268 activates a gene cascade related to the formation of long-term memory in the primate.