Scientists have discovered a new treatment for people suffering from diseases including Alzheimer's, dementia and depression involving stimulating the brain to produce more nerve cells.
Neurologists carried out tests on rodents to explore why fewer nerve cells for learning and memory were produced in older people's brains.
The study, funded by the National Institutes of Health and the US department of veterans affairs and appearing in the Neurobiology of Aging journal, refuted research suggesting aging brains produced fewer nerve cells.
In fact, the existing cells divided less regularly leading to reductions in the number of new neurons in the hub of the brain's learning and memory faculties called the hippocampus.
"This discovery provides a new avenue to pursue in trying to combat the cognitive decline associated with conditions such as Alzheimer's disease and with aging in general," said Bharathi Hattiangady, who led the study.
The Alzheimer's Association estimates that around 4.5 million Americans suffer from the disease, which destroys nerve cells in the brain, impairing memory and behaviour.