Repeat burst for timing code in excitatory neuronal network on multi-electrode array

Concise coding for input plays an important role in neural signal processing. In previous studies, three types of neural signal coding were raised: rate, timing and population coding. By multi-electrode array, the coding of input intensities in cultured hippocampal neuronal networks was examined. In excitatory neuronal network, responses to input intensities focused on the three periods: 1~10 ms, 11~30 ms, 41~60 ms. The dynamics on firing rate to input intensities in each timings was distinct: in 1~10 ms, the sublinear relationship to increasing input intensities was exhibited over the whole input range; in 11~30 ms, only a transition was occurred in inputs from 300 to 400mV; in 41~60 ms, a linear increase with input from 300 to 600 mV. These results suggest that the coding to input intensities was a complex mode that is repeat burst based-on timing in high density cultured neuronal network.