Over the past 25 years, neuroimaging has become a ubiquitous tool in basic research and clinical studies of the human brain. However, there are no reference standards against which to anchor measures of individual differences in brain morphology, in contrast to growth charts for traits such as height and weight. Here, we built an interactive online resource (www.brainchart.io) to quantify individual differences in brain structure from any current or future magnetic resonance imaging (MRI) study, against models of expected age-related trends. With the goal of basing these on the largest and most inclusive dataset, we aggregated MRI data spanning 115 days post-conception through 100 postnatal years, totaling 122,123 scans from 100,071 individuals in over 100 studies across 6 continents. When quantified as centile scores relative to the reference models, individual differences show high validity with non-MRI brain growth estimates and high stability across longitudinal assessment. Centile scores helped identify previously unreported brain developmental milestones and demonstrated increased genetic heritability compared to non-centiled MRI phenotypes. Crucially for the study of brain disorders, centile scores provide a standardised and interpretable measure of deviation that reveals new patterns of neuroanatomical differences across neurological and psychiatric disorders emerging during development and ageing. In sum, brain charts for the human lifespan are an essential first step towards robust, standardised quantification of individual variation and for characterizing deviation from age-related trends. Our global collaborative study provides such an anchorpoint for basic neuroimaging research and will facilitate implementation of research-based standards in clinical studies.

Although sensory input is continuous, we perceive and remember discrete events. Event segmentation has been studied extensively in adults, but little is known about how the youngest minds experience the world. The main impediment to studying event segmentation in infants has been a reliance on explicit parsing tasks that are not possible at this age. fMRI has recently proven successful at measuring adult event segmentation during task-free, naturalistic perception. Applied to infants, this could reveal the nature of their event segmentation, from low-level sensory transients to high-level cognitive boundaries. We collected fMRI data from 25 adults and 25 infants less than one year of age watching the same short movie. Neural events were defined by the stability of voxel activity patterns. In adults, we replicated a hierarchical gradient of event timescales, from shorter events in early visual regions to longer events in later visual and narrative regions. In infants, however, longer events were found throughout the brain, including in a second dataset. Infant event structure fit adult data and vice versa, but adult behavioral boundaries were differently expressed in adult and infant brains. These findings have implications for the nature of infant experience and cognition.