By contrast to the first film, which shows SACs from mice with control retinas, this one shows ex vivo live imaging of On SACs from mice with mutant retinas. The images were taken every 20 minutes for eight hours. In contrast to control On SACs, mutant On SACs fail to establish characteristic radially-symmetric dendritic morphology. Instead, these mutant dendritic processes remain entangled. This ultimately results in a deformed SAC and in altered retina function. This video relates to a paper that appeared in the 1 Nov., 2013, issue of Science, published by AAAS. The paper, by Lu O. Sun at he Johns Hopkins University School of Medicine in Baltimore, MD, and colleagues was titled, " On and Off Retinal Circuit Assembly by Divergent Molecular Mechanisms."