of equal fluid levels, and so the medium height was thereafter maintained equally between chambers. After 4–7 days of culture, massive extended neuronal processes were observed to pass through the microchannels connecting the outer and the central chamber (Fig. 2c) which formed synapselike boutons with neurons in the central chamber at 4–6 weeks post seeding (Fig. 2d,e). These results indicate that human neurons survive in the device for 4–6 weeks and sense dif usible, trophic signals from communicating chambers to drive process extension and potential synaptic interaction between chambers.
