Fig. 5: Theta-band oscillation, phase-amplitude coupling, and neuronal avalanches indicate complex activity in the connected organoids.

A Raw LFP plot from four electrodes of each of the connected organoids at 9 weeks. B Wavelet coherence between the two organoids exhibited synchronous activity in the theta band frequency. C Modulation index of PAC in delta-phase/gamma-power and theta-phase/gamma-power of the connected organoids cultured for 5, 7, and 9 weeks. n = 3 organoids. P = 0.0004 (delta, 5–9 weeks); 0.0016 (delta, 7–9 weeks); 0.0052 (theta, 5–9 weeks). D Delta-phase/gamma-power and theta-phase/gamma-power PAC modulation index of single, fused, and connected organoids. n = 3 organoids. P = 8e−7 (delta, single/connected); 9e−7 (fused/connected); 7.35e−5 (theta, single/connected); 0.0002 (fused/connected). E Intra- or inter-organoid PAC modulation index in the connected organoids. n = 16 from 4 organoids. F Schematic illustration of analyses of neuronal avalanches including the extraction of neuronal avalanche cascades. Neuronal avalanches were calculated from 8 electrodes. The cascade of single spikes was characterized at 3 msec scale size. G The log plot of neuronal avalanche size and probability at 5, 5.5, and 8.5 weeks of culture. *p < 0.05; One-way ANOVA with Tukey’s multiple comparison test. Data are presented as mean values ± SD.