The paper trail

1928 Histologist and Nobel laureate Santiago Ramon y Cajal writes in Degeneration and Regeneration in the Nervous System, "In adult centers the nerve paths are something fixed, ended, immutable. Everything may die, nothing may be regenerated."

Santiago Ramon y Cajal

1965 Joseph Altman and Gopal Das at the Massachusetts Institute of Technology are the first to describe neurogenesis in adult rat hippocampus, but Ramon y Cajal's dogma remains intact.

1977 Using radioactive thymidine labeling and electron microscopy, Michael Kaplan and James Hinds at Boston University find evidence of neurogenesis in the olfactory bulb and dentate gyrus of rat. Kaplan later writes in a 2001 Trends in Neurosciences article: "In the midst of a revolution one must chose allegiance, and during the 1960s and 1970s, those who chose to support the notion...