(c) Pseudo-color look-up table applied to mean nuclear Venus::HES5 intensity within motorneuron (MN) and interneuron (IN) domains, corresponding to segmented image in (a). (d) Dimension of microclusters in DV axis for MN and IN domains; microclusters counted contained cells with high and similar levels of HES5 (Materials and Methods); bars show mean ±SD; data consists of 34 microclusters measured from 5 sections and 3 independent experiments; 2-tailed Mann-Whitney test. **** p<0.0001. 