Fig. 6: Cortical microglial expansion during early postnatal development.

a-b Representative STPT images of Cx3cr1 microglia in the a primary auditory cortex (AUDp) and b temporal association cortex (TEa). c Temporal trajectory of Cx3cr1 microglial count vs. volume. Data are reported as mean ± s.d. (includes shaded area between error bars). d Microglial (Cx3cr1) and GABAergic (Gad2) cell density trajectories between P4 and P14 are significantly anti-correlated, as indicated by the calculated Pearson correlation coefficient (r = −0.9189, p < 0.0096 (two-tailed Student’s t-test)). Data are reported as mean ± s.d. (includes shaded area between error bars). e Averaged Cx3cr1 microglial density patterns across isocortical areas. f (left) Age-related variations in microglia densities were assessed using Bayesian global tests and pairwise comparisons. Detailed estimates and HPD intervals are available in Supplementary Data 1. (right) Functional data analysis (FDA) to examine significant differences between density patterns of isocortical Cx3cr1 cells between all age pairs (null, 0; ns, non-significant; two-tailed Student’s t-test: *p < 0.05; **p < 0.005, ***p < 0.001, ****p < 0.0001). g Isocortical flatmaps of Cx3cr1 microglial densities. h Microglial density patterns across four major striatal divisions of the caudoputamen (CP) from P4 to P14: dorsomedial CP (CPdm), dorsolateral CP (CPdl), ventromedial CP (CPvm), ventrolateral CP (CPvl). Color-coded asterisks (*) corresponding to CP subdivision indicate the time of emergence of significant microglial density differences. *p = 0.0191 for ventrolateral CP at P8, *p = 0.0155 for dorsolateral CP at P8, *p = 0.0447 for ventromedial CP at P8, and *p = 0.0434 for dorsomedial CP at P12. These p-values are adjusted after performing Dunnett’s T3 multiple comparisons test. Hash sign (#) indicates significance in microglial density differences between CP subdivisions. Data are reported as mean ± s.d. (includes shaded area between error bars). i Anatomical layout of the four functional domains (dorsomedial, yellow; dorsolateral, blue; ventromedial, magenta; ventrolateral, green) show a distinct Cx3cr1 microglial population increase in the ventrolateral CP from P4 to P14. See Source Data for Cx3cr1 microglial cell counts, density, volume measurements, and abbreviations.