Neurogenesis in the Adult Human Brain New neurons, shown in green, can be seen amid already established neurons, shown in red. In one area of the adult hippocampus, researchers found that each cubic centimeter of brain tissue contained from 100 to 300 new neurons (Eriksson & others, 1998). A later study by Kristy Spalding and her colleagues (2013) confirmed that more than a thousand new neurons are generated each day, even in older adults.
Photo courtesy Fred H. Gage, The Salk Institute, San Diego