Fig. 4

Approach by clustering to track sub-populations of microglial cells in the whole brain. a The scatter plots illustrate, at a single cell resolution, the CEA and CI characteristics and their frequency by cluster. The symbols “+” and “x” correspond to the centre of each cluster by the control and the LPS condition, respectively. The pie charts show the cluster frequencies by k-means clustering method (k = 4), and no significant difference has been observed between the two conditions using the chi-square test. b Four sub-populations have been defined by the cutoff (dotted lines) fixing the high (+) or the low (−) characteristic of one sub-population in the whole brain (WB). The cutoff was defined as the average of each morphological criterion (CI and CEA) in the control group. The centre of each cluster was plotted in the graph. The pie charts represent the proportions of sub-populations by condition. The same repartitions by sub-population as by cluster were observed