Abstract
The information processing of the living neuronal network is embedded in neuronal network dynamics. Rat hippocampal dissociated culture on the multielectrodes-array (MEA) dish is useful as a simple model of a brain information processing system, because it possesses essential functions for information processing in the brain. In addition, analysis of neuronal network activity in the small network is also important for development of an interface between a human and a robot. In this research, we analyzed the property of pattern repertories in neuronal network activity, and estimated stability and periodicity of the network dynamic pattern. We measured neuronal network activity from 64 microelectrodes of MEA dish and counted the number of spikes in 5 ms - time windows and constructed 64 degrees feature vectors from the number of spikes in 64 sites. The number of clusters of the feature vectors in 30 min recording was approximately 1000 in spontaneous activity and 600 in evoked activity. However, the number of clusters with over 1 % reproducibility was approximately 15 in both of spontaneous and evoked activity. In addition, we estimated number of the feature vectors with same patterns (reproducible patterns). As a result of these analyses, we confirmed that the same pattern of electrical activity repeated in a long-term culture of living neuronal network.
