A heavier cerebellum was linked to mental agility in a study of more than 37,000 adults
The cerebellum, the shriveled “little brain” nestled at the base of the skull, can help us stay alert as we age.
Regions at the back of the cerebellum that have resisted shrinking with age were linked to better mental or cognitive functioningeven in people in the early stages of Alzheimer’s disease, researchers report June 10 in Natural neuroscience.
Although traditionally considered a center of movement control, scientists now know that the cerebellum is a key player in cognition. Researchers also know that some parts of the cerebellum do not age in unison, but cerebellar aging is a relatively new area of research.
In the new study, the team first analyzed the brain scans and cognitive test results of more than 700 U.S. adults whose data was collected as part of the Human Connectome Project, a brain-mapping initiative. The test measured abilities including short-term memory, attention, language and viewing 3D objects.
A clear trend emerged: the cerebellum tends to become smaller with age, but the larger the cerebellum, especially in regions at the back of the small brain, the higher the score on cognitive tests. The trend held even after adjusting for participants’ different education levels, report Frederick d’Oleire Uquillas, a neuroscientist at Princeton University, and colleagues.
Researchers found the same link in more than 35,000 adults from the UK Biobank, a biomedical database. The results indicate that a larger cerebellum preserves cognition with age, says d’Oleire Uquillas. The researchers confirmed that scans of larger cerebellums showed more brain tissue and connections between nerve cells, a possible explanation for the protective effect.
To see if this trend persisted in brain diseases, the team turned to data from about 1,350 U.S. and Canadian adults as part of the Alzheimer’s Disease Neuroimaging Initiative. Among them, 644 had already accumulated a high level level of amyloid plaques which are a characteristic of the disease.
In the early stages of Alzheimer’s disease, before the appearance of a large cluster of amyloid plaques, a larger cerebellum was correlated with a higher cognitive score. Thus, the cerebellum could compensate for some of the damage caused by Alzheimer’s disease – up to a certain point, says d’Oleire Uquillas.
This is one of the largest and most comprehensive studies of cerebellar aging, says neuropsychologist Vonetta Dotson of Brigham and Women’s Hospital in Boston, who was not involved in the work. Dotson is the founder of a company that provides assessments, counseling and interventions to promote aging brain health.
“The more we understand [the cerebellum’s] role in both normal aging and disease, the more we can understand whether or not it should be a target for treatment when medical problems arise,” says Dotson.
For now, however, the research team cannot say whether the larger size of the cerebellum leads to better cognition in old age. The conclusions may also not apply generally; the majority of the study data came from white people with high levels of education.
But the suggestion of the cerebellum as a cognitive reserve leaves d’Oleire Uquillas optimistic about the prospects for aging and brain health. “It’s not all doom and gloom,” he says. “There is hope there.”