By Bin Lu and Niall Duncan
Recent years have seen a number of important themes come to the attention of the global neuroimaging community. The robustness of findings reported in the literature have been questioned as people begin to focus more on reproducibility and other statistical issues. At the same time, more attention is being paid to the variability between individuals, not least as efforts to develop diagnostic tools for different brain diseases advance. Databases of imaging data from very large samples have come to the fore as one way of tackling these issues and have already led to some striking results.
Researchers working in China are leading a number of these large-scale initiatives. In all, several thousands of participants have been scanned to acquire various MRI image types. These have been used to produce resources that are openly available to all. Here, we provide a brief overview of some of these resources to bring them to the attention of the community and let people know what is available to work with now, and what will be coming out in the near future.
Investigating the changes in the brain across the lifespan is a difficult endeavour but will help us understand how these changes affect us in health and disease. Large datasets are particularly useful in this context as they can capture the variability in developmental trajectory seen across the population. Understanding the brain in later life is a particularly prominent question within countries, such as China, that have rapidly aging populations.
The Southwest University Adult Lifespan Dataset (SALD) includes data from 494 individuals spanning an age range of 19 to 80 years. Each person has a T1-weighted anatomical image and a resting-state functional scan, along with rich phenotypic information available for download. This represents the largest raw data resource currently available involving participants living in China.
Two other large aging and development related initiatives are currently ongoing. The Beijing Aging Brain Rejuvenation Initiative (BABRI) project has been running for over a decade and has so far obtained multimodal imaging data from several thousand people over 50 years of age in the Beijing area. Each person also completes a battery of neuropsychological tests and various psychological questionnaires. The project, run by Beijing Normal University, aims to scan a total of 5000+ people. The Colour Nest Project, run by the Chinese Academy of Sciences Institute of Psychology is a longitudinal MRI project of participants aged between 6 to 84 years, and aims to scan up to 1200 people three times between 2016 and 2022.
Testing this sort of measurement reliability is also the aim of the Southwest University Longitudinal Imaging Multimodal (SLIM) dataset. This is a test-retest resource obtained from 241 young participants. Each person was scanned three times over a three and a half year period, with each session including anatomical, diffusion-weighted, and resting-state fMRI scans. It is also the aim of the global Consortium for Reliability and Reproducibility (CoRR) to which researchers based in China have been contributing and which has been partly led out of the Chinese Academy of Sciences. This dataset includes a large number of anatomical, diffusion weighted, rs-fMRI, and cerebral blood flow images from centres in China and around the world.
Hosting MRI data can be expensive and complicated due to the large amount of storage space required, especially as one gets to subject counts in the thousands. The R-fMRI Maps Project, run out of the Institute of Psychology at the Chinese Academy of Sciences, seeks to reduce this problem by hosting the final indices calculated on resting-state and structural data, rather than the data itself. Standardised pipelines are applied to the data by researchers to produce these indices and then the relatively small resulting files can be easily uploaded, along with other data such as demographics or cognitive test scores. This approach also has the advantage of reducing some of the privacy concerns associated with publicly sharing raw data.
One of the sets of indices hosted at the R-fMRI Maps Project is the REST-meta-MDD dataset. This represents one of the largest major depressive disorder (MDD) patient and control resources in the world with 2428 participants included (1300 patients) from sites all over China. The same processing pipeline was applied to all the participants and the resulting indices then uploaded to the central server. This resource is likely to be of great use in efforts to understand the variability contained within the MDD diagnosis.
Finally, the standard brain templates used in most neuroimaging analyses are made from one person or from small samples of people of European descent. There may be morphological differences between these templates and many of the people living in China that could affect the results of analyses. To address this problem the Chinese2020 project obtained anatomical images from 2020 people in mainland China and Hong Kong to create a brain template for the majority population in that region. The template is freely available for use, as is a conversion between it and MNI space.
As can be seen, there are many exciting projects going on in China, generating large amounts of data that is (or will be) available to researchers to investigate. These datasets are targeted at some of the main questions neuroimagers are currently focused on and have the potential to greatly advance our understanding of, amongst other things, brain development, aging, and psychiatric disorders.