Memory for context is impaired by injecting anisomycin into dorsal hippocampus following context exploration

Pre-exposure to the context facilitates the small amount of contextual fear conditioning that is normally produced by immediate shock. This context pre-exposure facilitation effect provides a convenient way to study the rat's learning about context. We recently reported that anterograde damage to dorsal hippocampus prevents this facilitation. The present experiments strengthen this conclusion by showing that the protein synthesis inhibitor, anisomycin, injected bilaterally into the dorsal hippocampus following context pre-exposure also significantly reduces the facilitation effect. The same treatment given immediately after immediate shock, however, had no effect on facilitation. These results support theories that assume that, (a) contextual fear involves two processes, acquiring and storing a conjunctive representation of a context and associating that representation with fears and (b) the hippocampus contributes to contextual fear by participating in the storag of the memory representation of the context. (C) 2002 Elsevier Science B.V. All rights reserved.