Fig. 4: Waveforms and amplitudes of myoelectric signals recorded by MSMEA.

a, b Overlay of 28 extracellular FP and 28 intracellular AP waveforms for 20 μm-microelectrode, respectively.c, d Amplitude heatmaps of extracellular FP and intracellular AP were recorded by 20 μm-microelectrode. e, f Overlay of 32 extracellular FP and 32 intracellular AP waveforms for 50 μm-microelectrode, respectively. g, h Amplitude heatmaps of extracellular FP and intracellular AP were recorded at 50 μm-microelectrode. i, j Overlay of 28 extracellular FP and 27 intracellular AP waveforms for 100 μm-microelectrode, respectively. k, l Amplitude heatmaps of extracellular FP and intracellular AP were recorded at 100 μm-microelectrode. m, n Overlay of 20 extracellular FP and 20 intracellular AP waveforms for 200 μm-microelectrode, respectively. o, p Amplitude heatmaps of extracellular FP and intracellular AP were recorded at 200 μm-microelectrode. q, r Overlay of 29 extracellular FP and 29 intracellular AP waveforms for 400 μm-microelectrode, respectively. s, t Amplitude heatmaps of extracellular FP and intracellular AP were recorded at the 400 μm-microelectrode. u–x Statistical plots of (u) extracellular FP SNR and intracellular AP SNR, (v) APD₅₀ duration, (W) single cell AP signal ratio and (X) AP yield. Statistical plots were analyzed for a sample size of n = 10 or 4 data per group and were expressed as mean ± sem. Significant differences were analyzed by one-way ANOVA, *, p < 0.05; **, p < 0.01; ***, p < 0.001; ****, p < 0.0001; NS, not statistically significant