Regularity and complexity analysis of cultured neuronal network spontaneous activity

To investigate the complexity of spontaneous activities of hippocampal neuronal network which cultured on multi-electrode arrays(MEA) substrate.The approximate entropy(ApEn),a new statistic,was introduced to quantify the amount of regularity and complexity in time-series data of neuronal different spontaneous firing patterns.The results indicated that the changes with time approximate entropy dynamic curves were distinction for different spontaneous firing patterns time-domain waveform.The ApEn value range of dynamic curves was 1.0-1.2 in periods of quiescence;the ApEn value was 0.2-0.6 during typical bursts firing pattern,and the dynamic curves trend was first decrease and then increase,a small oscillation final;the ApEn value was 0.2-0.7 during pseudo-burst firing pattern,but the dynamic curvrs were fluctuating along a line which parallels the time coordinate;the ApEn value was 0.8-0.9 during continuous single spike firing pattern;the ApEn value was 0.6-0.8 at random single spike firing pattern.This result showed that the approximate entropy could be used to effectively identify the different electrophysiological signals from the spontaneous activity of cultured neural network,and the ApEn dynamic curves also could be used to reflect the regularity and complexity change of the bursts and spikes firing process.Thus,it indicated that the ApEn algorithm had a potential wide applicability to analyze the neuronal signal.