Neuroscience: Reference charts for human brain development

Standardized reference charts for the development of the human brain throughout life are presented in Nature. These charts — constructed through the analysis of brain scans from more than 100,000 participants worldwide — could have potential future applications for the digital assessment of brain health and disease diagnosis at any age.

There are currently no standard references to quantify the maturation and healthy ageing of the human brain, unlike growth charts used to measure traits such as height and weight in children, for example. To address this issue, Richard Bethlehem, Jakob Seidlitz and colleagues collated data from 123,984 MRI brain scans of 101,457 individuals aged between 115 days after conception and 100 years old, from over 100 studies worldwide. The team created charts of normal brain development across a lifetime, which could be used to generate ‘centile scores’ to determine whether an individual is on a standard trajectory. These charts — which were separated according to sex — were stable in their predictions, despite study-specific differences in both the individuals assessed and the techniques and methods used. Critical developmental periods — such as an approximate 70% increase in the size of the brain between the time before 17 weeks after conception and 3 years of age — were revealed. The standard framework also enabled the detection of patterns of changes in brain anatomy associated with disease; for example, predictions of a transition from a diagnosis of mild cognitive impairment to that of Alzheimer’s disease.

The authors emphasise that substantial, future research will be needed before these results can be put into clinical practice. Caveats, such as potential data bias towards European and North American populations and individuals of European ancestry within these groups, will also need to be addressed. However, by providing these charts in an interactive, open-access format, they anticipate that the database will continue to evolve.