Figure 6.

Assessing the temporal persistency of hub and wave-initiator cells. (A) The evolution of relative node degrees in the functional β cell network within a sliding temporal window (width 300 s, step 20 [8 mM] and 5 [12 mM] s) in two typical islets with 8 mM (left) and 12 mM (right) glucose stimulation. The relative number of functional connections is color coded as indicated by the color bar. (B) Upper panels show the mean-field Ca²⁺ signal of the same two representative islets as in (A), and lower panels show raster plots indicating individual Ca²⁺ oscillations with color-coded activation sequence within individual Ca²⁺ waves. The ranks for oscillation onsets are color coded as indicated by the color bar, such that the red dots reflect the initiating cells within a given wave. (C) Average interlayer hub similarity as a function of interlayer distance n (left) and the average values of interlayer hub similarity (right). (D) The average values of wave-network interlayer initiator similarities (left) and the average wave-network interlayer initiator similarity as a function of the interlayer distance m (right). (E) Temporal variability of node degrees in correlation-based networks dependent on the node degree. Gray dots denote the values of individual cells, and the boxplots the 1/6 lowest, 2/3 intermediate, and 1/6 highest connected cells. (F) Temporal cellular activation rank variability dependent on the initiation parameter. Gray dots represent the values of individual cells, and the boxplots the 1/6 lowest, 2/3 intermediate, and 1/6 highest connected cells. Boxes determine the interval between the 25th and the 75th percentile, whiskers denote the 10th and the 90th percentile, and lines within the boxes indicate the median. (C–F) The pooled data from the following number of islets/cells: 8/865 (8 mM glc); 8/1103 (12 mM glc). Statistical significance: ^∗p < 0.05, ^∗∗p < 0.01, ^∗∗∗p < 0.001; n.s., not significant. Effect sizes: negligible – N (δ < 0.147), small – S (0.33 > δ ≥ 0.147), medium – M (0.474 > δ ≥ 0.33), or large – L (δ ≥ 0.474). To see this figure in color, go online.