American biologists found that in chimpanzees, bonobos, orangutans, and gorillas, the brain does not decrease in volume or mass with age. The study, based on observations of nearly three hundred primates in the United States, was published in PNAS.
TASS reports on the work of Professor William Hopkins of the University of Texas in the United States. Scientists studied brain aging in chimpanzees, bonobos, orangutans, and gorillas and found no signs of a noticeable decrease in brain mass with age in these animals.
The observations covered nearly three hundred higher primates living in nurseries and research centers in the United States. The sample included about 200 chimpanzees, eight bonobos, as well as several dozen gorillas and orangutans aged 5 to 70 years.
The researchers compared brain mass in apes from close age groups and separately compared the figures in females and males. According to their calculations, in all four primate species this indicator remained unchanged throughout life, including very elderly chimpanzees and gorillas older than 40–50 years.
The authors contrast these data with humans, in whom brain mass decreases on average by 2.2–2.7 g per year. According to them, by the beginning of the eighth decade of life these losses double, and at 45–50 years the human brain begins to shrink rapidly in volume and mass.
The study links this to the fact that humans live longer and are more strongly exposed to metabolic disorders and vascular diseases. In the scientists' view, this is what makes people especially vulnerable to brain atrophy and to a range of age-related diseases of the nervous system.
The authors note that previously the aging of the primate nervous system was studied at the level of individual synapses, neurons, and areas of the cortex, but not the brain as a whole. They believe that the absence of a pronounced decrease in brain size in great apes points to significant differences in the aging of the human brain and that of higher primates.
