Researchers have discovered a molecule that accumulates with age and inhibits the formation of new neurons. The finding might help scientists design therapies to prevent age-related cognitive decline.

The investigators identified the molecule, called Dickkopf-1 or Dkk1, in the brains of aged mice. By blocking production of Dkk1, “we released a brake on neuronal birth, thereby resetting performance in spatial memory tasks back to levels observed in younger animals,” says senior author Dr. Ana Martin-Villalba, of the German Cancer Research Center in Heidelberg.

Aged mice that lacked Dkk1 performed just as well as young mice in memory and recognition tests because the ability of the neural stem cells in their brains to self-renew and generate immature neurons in the hippocampus (involved in memory) was restored to youthful levels.

The investigators also found that young mice lacking Dkk1 were less susceptible to developing acute stress-induced depression than normal mice. This suggests that, in addition to slowing memory loss during aging, neutralizing Dkk1 (which is also present in human brains) could be beneficial in counteracting symptoms of depression.