During embryonic neurogenesis many ventricular zone progenitors divide to generate one daughter that retains progenitor potential and replenishes the ventricular progenitor pool while the other daughter becomes a neuron and migrates away to the developing grey matter. We have used the superior optics of the zebrafish brain and live imaging techniques to examine how this asymmetry in daughter fates is achieved and observe an unexpected twist to the origin of the neuron. Previous hypotheses had suggested that the daughter that inherits the apical domain is most likely to retain progenitor characteristics while the more basal daughter becomes the differentiated cell. However our time-lapse analyses shows that the cell destined to become a neuron is derived from the more apical of the two daughters, while the more basal daughter replenishes the apical progenitor pool. In addition we observe novel cell behaviours during the very early stages of neuronal differentiation that lead us to propose a new mechanism for generating neuronal spacing patterns in the spinal cord.