Do adult human brains renew their neurons?

TWO papers with starkly contradictory conclusions, published three weeks apart, have reignited debate about whether adult human brains can grow new neurons. For over a century, neuroscientists believed brains have acquired all the neurons they will ever have shortly after birth. But research over the past two decades has questioned this, producing evidence that new neurons are indeed generated in the adults of several species, people included. The matter is of more than just theoretical concern. Understanding how neurons are generated might lead to new ways of dealing with cognitive decline in ageing, neurodegenerative disease and even depression.

The conflicting studies both involved inspecting post-mortem brain samples using a technique called immunostaining. The first to press, by Arturo Alverez-Buylla and Shawn Sorrells of the University of California, San Francisco, was published on March 15th in Nature. It claims that neurogenesis happens rarely, if at all, in adults. The other, by Maura Boldrini and René Hen at Columbia University, was published on April 5th in Cell Stem Cell. It claims neurogenesis persists through adulthood at a largely unchanged rate.