From a 15-week-old fetus to a 100-year-old adult , an international team of researchers has created a series of life-spanning brain charts that now allow us to see how our brains evolve throughout life. . The neuroscientists involved in the study published in the journal Nature describe it as the most comprehensive effort to date to create a standard by which a person’s brain development can be measured throughout their lives.
These graphs are the result of a research project that spans six continents and brings together possibly the largest MRI data sets ever assembled: almost 125,000 brain scans from 101,457 people from more than 100 different studies (this is also due because fMRI of the brain is an expensive and time-consuming process, and a single computer cannot collect enough of the necessary data) and about two million hours of computer work time.
And no analogous reference tables existed to measure age-related changes in the human brain. Until now. Indeed, the lack of tools for standardized assessment of brain development and aging is crucial for the study of psychiatric disorders and for conditions such as Alzheimer’s disease that cause brain tissue degeneration and cognitive decline.
“There are no standardized growth charts for brain development like there are for other growth metrics such as height and weight, even though we know that the brain goes through many changes throughout human life,” he explains. neuroscientist Aaron Alexander-Bloch of the University. from Pennsylvania. “Our work brings together a large amount of imaging data that will continue to grow, allowing researchers and eventually clinicians to assess brain development against standardized measures.”
The new brain charts, which are available online, were put into a standard format that can be compared over time, including measurements of white and gray matter, and the volume of specific brain regions.
Brain diagrams have allowed experts to confirm, and in some cases show for the first time, developmental milestones that had previously only been hypothesized, such as at what age different areas of the brain reach maximum volume. When does this occur?
Our brains shrink as we age
According to the evolutionary map of the brain, which was born with the goal of creating a common language to describe the variability in brain development and maturation, our brains expand rapidly in the first years of life and slowly shrink as we age.
- Gray matter (brain cells) increases rapidly from mid-gestation, peaking just before the sixth birthday. Then they begin to slowly decrease.
- White matter (brain connections), also increases rapidly during early childhood, reaching its highest level just before we turn 29 and beginning to decrease in volume in our mid-30s. Thereafter, the decline accelerates as we turn 30. fifty.
- In addition, gray matter volume in the cerebral subcortex, which controls bodily functions and basic behavior, peaks in adolescence at age 14 1/2, the authors say.
Although this developmental brain map is not currently designed for clinical use, the researchers hope the charts will become a routine clinical tool similar to standardized pediatric growth charts. At the moment, the data sets already have about 165 different diagnostic labels.
“We are still at an extremely early stage with our Brain Charts, showing that it is possible to create these tools by bringing together large data sets. The charts are already starting to provide interesting insights into brain development and our ambition is that in the future , as we integrate more datasets and refine the graphs, they could eventually become part of routine clinical practice,” explains Richard Bethlehem, co-author of the paper. “You could imagine them being used to help assess patients screened for diseases like Alzheimer’s for example , which would allow doctors to detect signs of neurodegeneration by comparing how quickly a patient’s brain volume has changed compared to their peers.”
Referencia: R. A. I. Bethlehem et al. Brain charts for the human lifespan. Nature, 2022; DOI: 10.1038/s41586-022-04554-y