Interaction between living neuronal network and outer world by programmable multisite stimulation system

Rat hippocampal neurons organized complex networks on a culture dish which has 64 planner microelectrodes and action potentials of neurons were recorded from an individual electrode. MED64 system, one of multi site recording systems for extracellular action potential was used for recording network activities of living neuronal networks and for applying inputs from outer world to the network. Neurons reconstructed complicated networks along culture days, and a spatio-temporal pattern of spontaneous action potentials was drastically changed after transient high-frequency bursting activities (HFB). After HFB, spatial distribution of spontaneous action potentials changed to heterogeneous one. We designed programmable multisite stimulation head amplifier, and analysis of evoked action potentials induced by the stimulator confirmed that there are some hub-like structure which has many inputs from other neurons. In addition we are developing "biomodeling system", in which living neuronal network connected to moving robot.