Cultured cerebellar granule cells from Apex(Ref-1) heterozygous mutants manifest increased lethality compared to wild type cells following expo-sure to the redox cycling drug menadione. Cerebellar granule cells in culture were stained with fluorochrome (calcein-AM and propidium io-dide). Fluorescent images show live cells as green and dead cells as red. For details, see the article by Meira et al. on p. 5552 in this issue.