Fig. 5
Electrophysiological assessment of spontaneous activity in iPSCs-derived cortical-like neurons. A The image of a 24-well Axion microelectrode array (MEA) containing 16 electrodes and used for measuring the electrophysiological activity of neurons. iNSCs were cultured on MEA, and spontaneous excitatory activity was recorded during neuronal differentiation. B A representative raster trace of M3Low neurons in a well measured from an 8-min recording at day 70 of differentiation. Each horizontal row represents an electrode in the well. The spike histogram shows a synchronous network burst recording plotted over all electrodes (purple bar). C The alteration of spontaneous neuron activity in M3Low neurons at indicated time of differentiation (day 35, day 42, day 56, and day 70). D A plot represents mean firing rate (MFR), network burst numbers, and burst duration measured by the MEA. E Normal and MERRF-iNSCs were replaced in the MEA and allowed to undergo neuronal differentiation for 10 weeks, the spontaneous electrical activity of neurons was recorded over a period of 8 min. The plot represents the mean firing rate in neurons measured from day 29 to day 70 after neuron differentiation. Data were calculated as the average of 3 to 4 replicate wells of each neuron group in the experiment. F Mean firing rate in N and MERRF neurons at 7-week maturation. Data are presented as mean ± SEM, n = 3. *p < 0.05; **p < 0.01; ***p < 0.001