Old Brains Still Make Neurons, Study Finds, Offering a Possible Way to Protect Against Alzheimer's

A study published in Nature Medicine found aged brains from people lacking dementia have much higher rates of neurogenesis than those of persons with Alzheimer's, reports Stat . Study author María Llorens-Martín at Spain's Universidad Autónoma de Madrid said the molecular marker of neuron birth known as DCX does very poorly during tissue fixation, in which minuscule slices from a brain donated for postmortem study are prepared for analysis. She was aware that new neurons were present because after not finding them in samples that had undergone a long fixation time, her team again examined samples from the same brain that were fixed quickly. These exhibited clear molecular signs of having undergone neurogenesis until right before death — no matter what age it occurred — including the presence of doublecortin, a protein associated with neuronal migration. The Madrid team's findings correspond with a widely held view that healthy, adult brains produce new neurons, but at a rate that declines with age. The fact that certain seniors whose brains were full of amyloid plaque when they died, yet had no signs of dementia, suggests that although inflammation destroys neurons, high levels of neurogenesis may be replacing those cells to compensate.