, 2013, O’Reilly and McClelland, 1994 and Rolls and Kesner, 2006). Put into a computational perspective that has attracted considerable attention in recent years, the DG is critical for “pattern separation.” Pattern Ivacaftor clinical trial separation, as related to the DG, can be described as recoding cortical input information into a sparse, essentially orthogonal representation (McNaughton and Morris, 1987 and Treves and Rolls, 1992).

By manipulating the rate of adult neurogenesis, several groups of researchers have shown by ablating or overexpressing adult neurogenesis that newborn neurons are critical for making fine discriminations between neighboring spatial locations or highly similar environments in tests that reflect many of the computational characteristics of pattern separation (Clelland et al., 2009, Creer et al., 2010, Gu et al., 2012, Nakashiba et al., 2012 and Sahay et al., 2011). Together, these studies support the idea that a DG network dominated by young GCs is biased toward interpreting similar but not identical inputs as distinct, whereas older GCs are biased toward

interpreting similar inputs as equivalent. While adult neurogenesis in the DG is now generally accepted to occur in all adult mammals, there are many mechanistic details about how it takes place that will need to be determined before we have a more complete understanding of its functional contribution to hippocampus-mediated behaviors. That said, we need to know a lot more about PD184352 (CI-1040) Akt inhibitor how hippocampal circuits mediate

behaviors, and it is likely that understanding more about adult neurogenesis will contribute to a better understanding of hippocampal function. The field of stem cell biology changed forever when Takahashi and Yamanaka (Takahashi and Yamanaka, 2006) developed a simple and repeatable method to dedifferentiate mouse somatic cells (fibroblasts initially) to embryonic-like cells, termed induced pluripotent stem cells (iPSCs), that could give rise to every cell of the mouse body. The concept of reprogramming emerged from the early works of Briggs and King (Briggs and King, 1952) and Gurdon (Gurdon et al., 1958) but has become widely used as a technique since Takahashi and Yamanaka published their method and similar methods were shown to work for other species, including humans (Takahashi et al., 2007). A plethora of extensions and refinements followed, but the principle was established that essentially all cells in our body maintain an intrinsic plasticity for differentiating into a variety of cell types with completely different functions. The impact of this technology has been dramatic in all areas of biology but has been arguably most dramatic in the neurosciences. While much work remains to be done to improve and refine the technology, attempts to apply these techniques to the clinic are already ongoing.