About Science Snippets: These videos are short snippets from researchers' work--often videos actually used as data in a study or to demonstrate results in a paper. For context or additional explanation, check paper links and credits. Learn more: https://scim.ag/2veEw8U Read the paper (free): https://scim.ag/2AE9iNX S. Kang et al. Science Advances 2018 DOI 10.1126/sciadv.aas8772