%0 Journal Article
%T Hippocampal function is not required for the precision of remote place memory
%A Takashi Kitamura
%A Reiko Okubo-Suzuki
%A Noriko Takashima
%A Akiko Murayama
%A Toshiaki Hino
%A Hirofumi Nishizono
%A Satoshi Kida
%A Kaoru Inokuchi
%J Molecular Brain
%D 2012
%I BioMed Central
%R 10.1186/1756-6606-5-5
%X To directly test this idea, we introduced a new procedure: a non-associative place recognition memory test in mice. Combined with genetic and pharmacological approaches, our analyses revealed that place memory is precisely maintained for 28 days, although the recall of place memory shifts from hippocampus-dependent to hippocampus-independent with time. Moreover, the inactivation of the hippocampal function does not inhibit the precision of remote place memory.These results indicate that the quality of place memories is not determined by brain regions on which the memory depends.The hippocampus is a key brain structure for learning and memory [1-3]. Recall of some associative and spatial memories initially depends on the hippocampus, but that hippocampal dependency progressively decays over time, a process that is associated with a gradual increase of neocortex-dependency [4-9]. It has been suggested that the quality of original memories also transforms from a precise (i.e., detailed) form to a less precise (i.e., more schematic or generic) form with similar time course [10-12]. The question arises of whether changes in the quality of the original memories depend on the shift in brain regions on which the recall of these memories relies, i.e., whether the hippocampus is always required for the precision of memories. This is an important question for understanding physiological significances of the hippocampal-cortical complementary memory systems.There are several studies that address this issue in rodents. Using a contextual fear conditioning paradigm, which is an associative learning between a place and aversive experience, some studies demonstrated that the hippocampus is always necessary for the precision of place memories [13,14], supporting the memory transformation view [11] in which the quality of place memory correlates with the brain region on which that memory depends. By contrast, another study demonstrated that the hippocampus is not required for memory
%U http://www.molecularbrain.com/content/5/1/5