Researchers Find Evidence That Brains Are Getting Bigger

A new study suggests our brains might be growing larger over time. This finding could prove useful in fighting memory loss as we age.

Researchers at UC Davis Health found the brains of individuals born in the 1970s were bigger by about 6.6 percent and had a 15 percent larger surface area compared to those born in the 1930s. The new study was published in March in “JAMA Neurology.”

Charles DeCarli, the lead researcher of the study and a distinguished professor of neurology at UC Davis, told ScienceDaily that while genetics is a big factor in brain size, their findings suggest that other factors such as health, social interactions, culture, and education may also have an impact.

Brain size increased by 6.6 percent between the 1930s and 1970s

The researchers analyzed data from the Framingham Heart Study, a long-term community study based in Framingham, Massachusetts, spanning seventy-five years and involving multiple generations, as reported by the New York Post.

Between March 1999 and November 2019, scientists examined brain scans of 3,226 participants born between 1925 and 1968. They found a consistent trend. Brain volume increased gradually over time.

In the 1930s, the average brain volume was 1,234 millimeters, while by the 1970s, it had risen to 1,321 millimeters, marking a 6.6 percent increase.

Similarly, the cortical surface area, or the brain’s outer layer, also expanded from 2,056 square centimeters in those born in the 1930s to 2,104 square centimeters in those born in the 1970s.

Increase in size of gray matter, white matter, and the hippocampus

The researchers also noted an increase in the size of gray matter, white matter, and the hippocampus—an area linked to learning and memory.

White matter, situated in the brain’s inner tissues, consists of nerve fibers facilitating communication between different regions. It gets its name from the white myelin sheath covering the nerves.

On the other hand, gray matter, located in the brain’s outer layer, governs movement, memory, and emotions. It gets its name from the dense concentration of neuronal cell bodies, which impart a grayish color to the tissue.

The findings bring hope, as they suggest a potential decline in age-related dementias such as Alzheimer’s, according to scientists.

“Larger brain structures like those observed in our study may reflect improved brain development and improved brain health,” DeCarli explained. “A larger brain structure represents a larger brain reserve and may buffer the late-life effects of age-related brain diseases like Alzheimer’s and related dementias.”