US researchers have discovered a gene that may help explain why some people who lead enriching lives are less prone to Alzheimer's and age-related dementia.

Many people develop Alzheimer's or other forms of dementia as they get older. However, others remain sharp well into old age, even if their brains show underlying signs of neurodegeneration. Among these cognitively resilient people, researchers have identified education level and amount of time spent on intellectually stimulating activities as factors that help prevent dementia.

The study, led by researchers at the Massachusetts Institute of Technology, showed that this kind of enrichment appears to activate a gene family called MEF2, which controls a genetic programme in the brain that promotes resistance to cognitive decline.

The researchers observed this link between MEF2 and cognitive resilience. The findings suggest that enhancing the activity of MEF2 or its targets might protect against age-related dementia.

"It's increasingly understood that there are resilience factors that can protect the function of the brain," said Li-Huei Tsai, Director of MIT's Picower Institute for Learning and Memory.

"Understanding this resilience mechanism could be helpful when we think about therapeutic interventions or prevention of cognitive decline and neurodegeneration-associated dementia," Tsai added. The study appears in the journal Science Translational Medicine.

The MIT team set out to try to figure how environmental factors, such as education level, type of job, number of languages spoken, affect the brain at the neuronal level. They looked at human datasets and mouse models in parallel, and both tracks converged on MEF2 as a critical player.

In two human datasets comprising slightly more than 1,000 people altogether, the MIT team found that cognitive resilience was highly correlated with the expression of MEF2 and many of the genes that it regulates. 

The findings suggest that enhancing MEF2 activity could help to protect against dementia, but, because MEF2 also affects other types of cells and cellular processes, more study is needed to make sure that activating it wouldn't have adverse side effects, the researchers said.