Fig. 4: Cartesian functional connectivity and correlation coefficiency of islets before and after VSG or Sham surgery.

a Cartesian functional connectivity maps displaying the correlation coefficients of β-cells within the x–y position of analysed cells (dots). (i, ii) Example of islet implanted in sham animal at week (−1) and week 10. (iii, iv) Example of islet implanted in VSG-treated animal at week (−1) and week 10. Cells are connected with a line where the strength of each cell pair correlation (the Pearson R coefficient) is colour coded: red for R of 0.76–1.0, yellow for R of 0.51–0.75, green for R of 0.26–0.5 and blue for R of 0.1–0.25. Red dots represent β-cells with the highest number of connected cell pairs. Ca²⁺ activity detected during the 30 s (100 frames) imaging period analysed is displayed at the top right of each connectivity map. b The percentage of significantly connected cell pairs decreased significantly in the sham group at week 10 (p = 0.02). c Representative heatmaps depicting connectivity strength (Pearson R correlation) of all β-cell pairs (x–y axis) presented in (a). (i, ii) Example of islet implanted in sham animal (black) at week (−1) and week 10 (iii, iv). Example of islet implanted in VSG-treated animal (red) at week (−1) and week 10. R values colour coded from 0 to 1, blue to red, respectively. Red represents β-cell pairs with high connectivity strength. d The average of correlation coefficient (R) decreased significantly in the sham group at week 10 (p = 0.023). Sham group (n = 6 animals, n = 13 islets) and VSG (n = 10 animals, n = 15 islets) up until week 8, then sham (n = 3 animals, n = 3 islets) and VSG (n = 3 animals, n = 3 islets) on week 10. Data are means ± SEM and *p < 0.05 following two-way ANOVA (adjusted for multiple comparisons). VSG vertical sleeve gastrectomy. Source data are provided as a Source Data file.