Mouse Models for Studying Hippocampal Adult Neural Stem Cell Biology

The mammalian hippocampus shows a remarkable capacity for continued neurogenesis throughout life. Newborn neurons, generated by the radial neural stem cells (NSCs), are important for learning and memory as well as mood control. During aging, the number and responses of NSCs to neurogenic stimuli diminish, leading to decreased neurogenesis and age-associated cognitive decline and psychiatric disorders. Thus, adult hippocampal neurogenesis has been the subject of intense investigation, generating both excitement and controversy. Identifying the core molecular machinery responsible for NSC preservation is of fundamental importance if we are to use neurogenesis to halt or reverse hippocampal age-related pathology. Here, we briefly overview the most frequently used mouse models to study hippocampal neurogenesis and then focus on a unique mouse model that allows NSC-specific studies based on their unique expression of lunatic fringe (Lfng). The Lfng-eGFP and Lfng(BAC)-CreER^T2;RCL-tdT transgenic mice provide us with an excellent tool to resolve long-standing questions regarding the properties of NSCs, such as their specific molecular composition, potency, and plasticity, in isolation from any other cell in the hippocampal neurogenic niche.