Hippocampal expression of c-fos is not essential for spatial learning

The formation of long‐term memory is thought to involve underlying changes in synaptic strength. Many studies have focused on the mechanisms of spatial learning behavior in mammals that is critically dependent on the proper function of the hippocampus. Because of the enduring nature of long‐term memory, it is thought that gene expression is involved in this process. The immediate early gene (IEG) c‐fos encodes a transcription factor. The c‐Fos proteins form heterodimeric proteins with the c‐Jun family proteins and the resulting AP‐1 transcription complex plays a key role in coupling short‐term events elicited by stimuli received at the cell membrane to long‐term neuroplastic changes by regulating gene expression. c‐fos is induced in the hippocampus after spatial learning. Despite this knowledge, the precise role of c‐fos in memory formation and the underlying mechanisms remain unknown. To start investigating the role of c‐fos in learning and memory and underlying mechanisms, we evaluated spatial learning capabilities using mice carrying a hippocampal region‐specific mutation of c‐fos. We found that the c‐fos mutant mice exhibit normal spatial learning behaviors in both the Morris water maze and the Barnes maze tests compared to control mice. Our results suggest that hippocampal c‐fos expression is not essential for spatial learning. Synapse 46:91–99, 2002. © 2002 Wiley‐Liss, Inc.