stage 1 neuroblast FBbt:00001370 The first neuroblast subpopulation delaminating from the ventral neurectoderm towards the end of the second mesodermal cell division, shortly after gastrulation (Hartenstein and Campos-Ortega, 1984). These neuroblasts are generally arranged in two fairly regular longitudinal rows (the medial and lateral longitudinal rows), with a few cells scattered in an intermediate row. Doe (1992) defines the end of S1 as being early embryonic stage 9 following the development of NB3-2. SI neuroblast fly_anatomy.ontology S1 neuroblast Figure 7 of Hartenstein and Campos-Ortega, (1984), graphically depicts the pattern formed by the population of neuroblasts for the left half of the germ band. VFB:FBbt_00001370 neuroblast