In the presented thesis work, an “Optical Network Electrophysiology “ system that combines optical stimulation using optogenetic tools and multisite neuronal recording using microelectrode arrays was developed and its applicability to address questions related to neuronal network dynamics was demonstrated. The system was used to modify the intrinsic collective dynamics of a cultured neuronal network potentially maximizing spike synchronization using mild whole field photostimulation. It offers an attractive alternative to stimulation paradigms that externally control neuronal networks. Another application of the system was to drive neurons in a naturalistic in-vivo like fashion where fluctuating light waveforms where used to put neurons in “fluctuation driven regime”. This regime is crucial to characterize basic computational properties of neurons such as frequency-input curves, spike triggered average and correlation gain.