Neural stem cells give rise to cells with diverse morphologies and functions in the brain as a result of precisely controlled effects in space and time. The phenotype of the differentiated neuron is determined partly by its own history (e.g. from which part of the nervous system it originates; when it formed during development; what epigenetic pattern it carries) and partly by the environmental influences it is exposed to (e.g. ionic environment; presence of neurotransmitters; activity of the forming network). Clarification of this developmental biology is important because this knowledge may also help to develop the appropriate phenotype of neurons that can be derived from adult human epithelial cells by genetic reprogramming, advancing the development of human neurodegenerative disease models.The basic question of our research is to what extent the differentiation of neurons and the maturation of their physiological properties are influenced by temporal changes in their electrical activity, i.e., to what extent longer time scales, different frequencies and patterns of inputs “tune” the development of a neuronal phenotype or network activity.