Fear conditioning in inbred mouse strains: an analysis of the time course of memory.

Three mouse strains were examined for short- and long-term memory for Pavlovian fear conditioning measured 1 hr and 24 hr after conditioning. Both DBA/2J and CBA/J mice exhibit reduced long-term memory for contextual fear conditioning compared with C57BL/6J mice. In cued fear conditioning, however, DBA/2J mice show reduced short- and long-term memory compared with C57BL/6J mice, whereas CBA/J mice exhibit reductions only in short-term memory. These results underscore the importance of examining the time course of memory retention, and they suggest that inbred mouse strains may provide a diversity of phenotypes. The results also suggest that the processes of short- and long-term memory storage as well as contextual and cued fear conditioning are dissociable and are mediated by genetically distinct neurobiological mechanisms.