Fig. 5. Ciliary neurons transiently co-express cholinergic and noradrenergic marker genes. Double in situ hybridization for VAChT (red) and TH (black) at stage 24 shows the presence of cells that co-express VAChT and TH (white arrowheads) or only express VAChT (red arrowhead) or TH (black arrowhead). The VAChT signal in double-stained cells (white arrowheads) is low but significantly above background, as illustrated by comparison with cells devoid of VAChT expression (black arrowhead). Scale bar: 25 µm.