Credit: Image courtesy of Filipe Pinto-Teixeira and Cell.
A 3D reconstruction of a developing fly optic lobe, also represented in the accompanying video. In purple and dark gray are two types of neuroprogenitor-producing neuroepithelia. T4/T5 neuprogenitors (red) originate from the gray neuroepithelium to divide and produce T4 and T5 neurons (green), illustrating how neurons used in the perception of motion form in the brain of a fly.