The process of learning that neurogenesis actually exists has taken almost a century and has progressed slowly so far. In the late 1800s, scientists worldwide, including the prestigious Spanish researcher, Santiago Ramon y Cajal (1913), maintained that neurogenesis was a process restricted to brain development that ceased after birth. This conclusion was the result of studying the histology of the brain with the techniques of the time, such as Nissl and silver impregnation. Most researchers defined neurons as cells that were characterized by the presence of dendritic arborizations. When dendrites were not well developed, cells were thought to be in the process of differentiation, plastic changes, or the result of a histological artifact. © 2009 Springer-Verlag Berlin Heidelberg.
