Distinct subsets of motor neurons have been generated from human embryonic stem cells reports a study in Nature Communications this week. These findings could further our understanding of motor neuron development and diseases where motor neurons are affected.Siddharthan Chandran and colleagues cultured human embryonic stem cells under defined culture conditions and found that in the presence and absence of retinoic acid — a metabolite of vitamin A — different types of neurons could be generated. In their experiments they generated lateral and medial motor columnar motor neurons. The culture protocol allows the generation of a greater variety of motor neurons for use in further studies.