stage 1 neuroblast neuroblast MP2 FBbt:00001382 VFB:FBbt_00001382 Midline precursor cell that forms during the first wave of delamination in the medial column and divides only once (Schmid et al., 1999). In the embryo, one of these cells can be found in each hemisegment from S3-A10 and three are found in S1 (Birkholz et al., 2013; Urbach et al., 2016). In abdominal and thoracic segments, it produces the intersegmental interneurons dMP2 and vMP2 (Schmid et al., 1999). fly_anatomy.ontology segmentally-repeated neuroblast