Scientists at the University of California, Davis analyzed a study that has been ongoing for 75 years and found that the human brain has become increasingly larger: participants born in the 1970s had a brain capacity 6.6% larger than those born in the 1930s; The surface area of the brain is almost 15% larger. Researchers believe that an enlarged human brain or an increase in brain reserves may lower the overall risk of age-related dementia. The relevant paper was published in the Journal of Neurology of the American Medical Association on the 25th. Researchers analyzed brain magnetic resonance imaging (MRI) data from participants in the Framingham Heart Study (FHS). FHS was launched in Fremingham, Massachusetts in 1948, with the aim of analyzing patterns of cardiovascular and other diseases, and has been ongoing for 75 years. The latest study compared MRI data from 3226 participants born in the 1930s (the former) with those born in the 1970s (the latter). It was found that some brain structures, including brain capacity, have steadily increased year by year. For example, the average brain volume of the latter is 1321 milliliters, while the former is 1234 milliliters, an increase of about 6.6%. In addition, the average brain surface area of the latter is 2104 square centimeters, while that of the former is 2056 square centimeters, an increase of almost 15%. Moreover, the size of brain regions such as white matter, gray matter, and hippocampus (brain regions involved in learning and memory) has also increased. The research team said that a larger brain might mean a lower incidence rate of dementia. According to data from the Alzheimer's Association, approximately 7 million Americans currently suffer from Alzheimer's disease, and it is expected that this number will increase to 11.2 million by 2040. Although the number of patients has increased with the aging of the American population, the incidence rate is declining. A previous study found that since the 1970s, the incidence rate of dementia has dropped by 20% every decade. The improvement of brain health and the increase in brain capacity may be one of the reasons. (Lai Xin She)