An insightful study analyzing what contributes to the sharpness of mind in old age has found evolutionary hints.
The study, which was published in the peer-reviewed Chinese journal Science Bulletin, found that more developed frontal lobes were associated with sharp minds in some old people. The reason behind this occurrence may be attributed to natural selection in human evolution.
“Our team initiated the Beijing Ageing Brain Rejuvenation Initiative in 2008, which focused on elderly people with cognitive impairment because they needed more attention. But during our community-based research, we found there was a group of elderly people who aged more slowly and had a higher quality of life,” Chen Yaojing, study corresponding author and a researcher at Beijing Normal University, said, reported South China Morning Post. “We want to learn from them and find out ways to keep our brain in a healthier state.”
It was found during the study that people who had successful cognitive aging (SCA) had a better preserved frontal region of the brain. Meanwhile, people with mild cognitive impairment (MCI) exhibited structural deterioration in the temporal region of the brain.
The authors put forward a “frontal preservation, temporal impairment (FPTI)” hypothesis to provide an explanation for the differences in individuals’ cognitive aging.
The frontal lobes are associated with cognitive functions, such as decision-making, problem-solving, and attention. Interestingly, the frontal lobes are one of the main features that separate human beings and animals. The frontal lobes are proportionally larger in humans than in other species of animals.
Chen said the human frontal lobe was the most recent one to evolve and it exhibited age-related decline faster than other abilities.
“There’s a theory called ‘last in, first out’. The newest part in evolution will decline first because human beings tend to save their survival abilities to the end,” Chen said. “So, for most elderly people, the functions of their frontal lobes decline early. But for people with successful cognitive aging, their frontal lobes are preserved well.”
The temporal lobes are responsible for processing auditory information and preserving memory. Structural abnormalities in this region have been associated with pathological cognitive aging, according to researchers.
Three groups of older adults aged between 70 and 88 were recruited for the study. These included 64 successful cognitive aging individuals, 68 mild cognitive impairment patients, and 66 cognitively normal controls.
For the study, Chen and her colleagues analyzed gray matter volume, gray matter networks, and white matter network characteristics of the three groups.
Compared to the other two groups, the SCA group performed better on all three parameters.
“If our hypothesis is proven true, in the future we can develop the frontal lobes or slow the aging of temporal lobes,” Chen concluded. “This is a multidisciplinary effort.”