Human and mouse brains age in surprisingly similar ways, study finds

A new study has revealed striking similarities between how human and mouse brains age. Researchers found that both species experience a breakdown in the brain's specialised networks as they grow older. This discovery could open doors for testing treatments to slow or reverse cognitive decline.

The team used advanced scanning techniques to track brain changes in mice over time. Their findings suggest that mice may offer a useful model for studying human brain aging in a much shorter lifespan.

Scientists scanned the brains of 82 mice at different ages, from 3 to 20 months, using non-invasive functional MRI (fMRI). Due to the tiny size of mouse brains—around 3,000 times smaller than human brains—stronger MRI magnets were needed to capture detailed images. The study included three mouse species: Mus musculus (common lab mice), Mus spretus (a wild species), and Mus caroli (a distant relative). Genetic differences, such as variations in neuroinflammation and synaptic plasticity genes, as well as behavioural traits like activity levels and stress resistance, influenced how their brains aged. Notably, Mus spretus showed slower neuronal decline.

The results mirrored patterns seen in human aging. Both mice and humans lost 'modular specialisation'—the ability of distinct brain regions to work efficiently together. However, human brains, being more interconnected, declined faster than those of mice. This greater connectivity may contribute to higher intelligence but also makes them more vulnerable to rapid age-related deterioration. Mice provide a practical advantage for research because their lifespan compresses aging from the equivalent of human ages 18 to 70 into just 17 months. This accelerated timeline allows scientists to test potential anti-aging interventions more quickly and efficiently.

The study highlights how mouse models could help unravel the mechanisms behind brain aging. By identifying shared patterns between species, researchers may develop strategies to combat cognitive decline. The findings also underscore the value of using diverse mouse species to better understand genetic and behavioural influences on aging.