Human brains grow quickly in childhood, then slowly shrink over the rest of our lives. Neurologists knew this, but never had a reference for normal size variations in brains -until now. A catalog of 120,000 brain scans from more than 100,000 people have been compiled into a kind of "growth chart" by a team led by neuroscientist Jakob Seidlitz of the University of Pennsylvania. It is a massive project, and Seidlitz was impressed with how many colleagues participated by donating scans, surmising they had more time to reply to emails due to the pandemic.
The scans show that different parts of the brain expand and contract at different rates. For example, cortical thickness peaks in late infancy, while ventricular volume begins a growth spurt that only starts in adulthood. The growth chart can be used to determine what is normal for brain development and size by age, but they caution that the project is not exactly representative of the global population. These scans come from mainly white patients in relatively wealthy nations, because MRI scanners are expensive and not commonly found in many countries of the world. But it's a start, and this catalog will be a big help to researchers and physicians alike. Read more about this project at Nature.
(Image credit: Zephyr/SPL)