 is the first demonstration of murine neural stem and progenitor cell-derived functional synapse and neuronal network formation on a 3D collagen matrix.The neural progenitor cells expanded and spontaneously differentiated into excitable neurons and formed synapses; furthermore, they retained the ability to differentiate into the three neural tissue lineages.It was also demonstrated that not only active synaptic vesicle recycling occurred, but also that excitatory and inhibitory connections capable of generating action potentials spontaneously were formed.